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Tytuł:
Magnetocaloric Effect of the $Tb_{1-x}Y_{x}NiAl$ and $TbNiAl_{1-y}In_{y}$ Series
Autorzy:
Kaštil, J.
Javorský, P.
Klicpera, M.
Powiązania:
https://bibliotekanauki.pl/articles/1534279.pdf
Data publikacji:
2010-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Sg
Opis:
We have studied the development of the magnetocaloric effect in the (Tb,Y)NiAl and TbNi(Al,In) series as determined from magnetization measurements. The transition from antiferromagnetic order in TbNiAl to ferromagnetic order in $Tb_{0.7}Y_{0.3}NiAl$ is accompanied by increase of the maximum entropy change from - 4.1 to - 4.4 J $kg^{-1} K^{-1}$. In the TbNi(Al,In) series, the change of uniaxial anisotropy in TbNiAl to the easy-plane anisotropy in TbNiIn leads to broadening of the magnetocaloric effect accompanied with large increase of the relative cooling power from 66 to 120 J $kg^{-1}$.
Źródło:
Acta Physica Polonica A; 2010, 118, 5; 888-890
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetocaloric Effect in Ni-Cu-Mn-Gd-Ga Alloy. XI Symposium of Magnetic Measurements
Autorzy:
Sielicki, K.
Wróblewski, R.
Leonowicz, M.
Powiązania:
https://bibliotekanauki.pl/articles/1402340.pdf
Data publikacji:
2015-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Sg
Opis:
The magnetocaloric effect of the Ni-Cu-Mn-Gd-Ga polycrystalline alloy was investigated. The nominal composition of the alloy was $Ni_{50}Cu_{6.25}Mn_{16.75}Ga_{25}Gd_{2}$ at.%. The X-ray diffraction studies revealed presence of two phases at room temperature. This was confirmed by magnetic measurements conducted in low field of 4 kA/m (50 Oe), which showed two Curie transition temperatures, one in vicinity and the other one well above the room temperature. The analysis of isothermal magnetic curves allowed the calculation of magnetic entropy change ($\Delta S_{M}$). Although the peak value of $| \Delta S_{M}|$ is relatively low, ≈1.1 J/(kg K), it is very broad. The adiabatic temperature change (ΔT) measured near room temperature is ≈0.49 K. Such result is irrespective of the magnetizing-demagnetizing cycle frequency which varied from 2/min to 10/min.
Źródło:
Acta Physica Polonica A; 2015, 128, 1; 120-122
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Comparative Studies of Magnetocaloric Effect in Ni-Mn-Cu-Ga and Ni-Mn-Pb-Ga Alloys
Autorzy:
Sielicki, K.
Wróblewski, R.
Leonowicz, M.
Powiązania:
https://bibliotekanauki.pl/articles/1388040.pdf
Data publikacji:
2015-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Sg
Opis:
Effect of Pb substitution for Cu on magnetocaloric properties of $Ni₂Mn_{1-x}Cu_xGa$ (x = 0.25, 0.27, 0.29) alloy was investigated experimentally. The magnetic measurements of Ni-Mn-Pb-Ga alloys conducted at low field of 4kA/m (50 Oe) showed that their Curie points are above the room temperature (RT). The analysis of isothermal magnetic curves allowed the estimation of magnetic entropy change $(ΔS_{M})$. The highest calculated value of $|ΔS_{M}|,$ ≈ 12 J/(kgK) and ≈ 1.8 J/(kgK), was registered for alloys containing 6.25 at.% of Cu and 6.75 at.% of Pb, respectively. The adiabatic temperature changes (ΔT) measured near RT are ≈ 0.4 K.
Źródło:
Acta Physica Polonica A; 2015, 127, 2; 644-646
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetocaloric effect in antiferromagnetic half-Heusler alloy DyNiSb
Autorzy:
Synoradzki, K.
Ciesielski, K.
Kaczorowski, D.
Powiązania:
https://bibliotekanauki.pl/articles/1050664.pdf
Data publikacji:
2018-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Ee
75.30.Sg
Opis:
The low-temperature magnetic, thermal and magnetocaloric properties of the half-Heusler compound DyNiSb were studied on polycrystalline samples. The temperature variations of the magnetization and the heat capacity revealed a phase transition from paramagnetic to antiferromagnetic state at the Néel temperature T_{N} = 3.1 K. The compound exhibits normal and inverse magnetocaloric effect with the isothermal magnetic entropy change reaching 5.2 J/(kg K) at 4.8 K for a magnetic field change of 3 T. The estimated refrigerant capacity is about 58 J/kg.
Źródło:
Acta Physica Polonica A; 2018, 133, 3; 691-693
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigations of the magnetization reversal processes in nanocrystalline Nd-Fe-B alloys doped by Nb
Autorzy:
Kaźmierczak, M.
Pawlik, P.
Wysłocki, J.
Wnuk, I.
Gębara, P.
Pawlik, K.
Przybył, A.
Powiązania:
https://bibliotekanauki.pl/articles/1052622.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Sg
75.50.Bb
Opis:
In the following article the magnetic properties and phase composition of (Nd₁₀Fe₆₇B₂₃)_{100-x}Nb_{x} (where x=5, 6, 7, 8, 9) alloys in the form of ribbons are discussed. The X-ray diffraction studies revealed the coexistence of amorphous and nanocrystalline structures consisting of Nd₂Fe₁₄B, Nd_{1+ε}Fe₄B₄ and metastable Nd₂Fe₂₃B₃ phases. The shape of M_{rev} (M_{irr}) suggests that the magnetization reversal proceeds through the nucleation of the reversal domain for the ribbon doped with 5-7 at.% of Nb and the subsequent pinning of the domain walls for ribbons doped with 8 and 9 at.% of Nb.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 789-791
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of Critical Behavior in Gd₇₅Ge₁₅Si₅Ce₅ Alloy
Autorzy:
Gębara, P.
Hasiak, M.
Powiązania:
https://bibliotekanauki.pl/articles/1055116.pdf
Data publikacji:
2017-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Sg
75.50.Bb
Opis:
The main goal of the present work was to study the critical behavior in the as-quenched Gd₇₅Ge₁₅Si₅Ce₅ (wt%) in the vicinity of the critical temperature T_{C}. The second order phase transition from a ferro- to a paramagnetic state was confirmed by the positive slope of the Arrott plots and analysis of temperature evolution of the Landau coefficients. The critical exponents have been revealed using the Kouvel-Fisher method and yield β=0.376±0.006, γ=1.032±0.006 and δ=3.835±0.008. The Curie temperature for the as-quenched Gd₇₅Ge₁₅Si₅Ce₅ equals 275.7±0.1 K.
Źródło:
Acta Physica Polonica A; 2017, 131, 5; 1232-1235
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Structural and Magnetocaloric Study οf the $LaFe_{11.0}Co_{0.8}(Si_{0.4}Al_{0.6})_{1.2}$ Alloy
Autorzy:
Gębara, P.
Pawlik, P.
Škorvánek, I.
Marcin, J.
Wysłocki, J.
Powiązania:
https://bibliotekanauki.pl/articles/1534407.pdf
Data publikacji:
2010-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Sg
75.50.Bb
Opis:
In this study, we have investigated the microstructure and magnetic entropy change of annealed $LaFe_{11.0}Co_{0.8}(Si_{0.4}Al_{0.6})_{1.2}$ alloy in a form of bulk samples and melt-spun ribbons. The bulk samples were annealed at 1323 K for 20 and 49 days and the maximum values of the magnetic entropy change $| ΔS_M |$ obtained after the change of external magnetic field from 0 to 5 T reached 7.5 J $kg^{-1} K^{-1}$ and 7.7 J $kg^{-1} K^{-1}$, respectively. For the melt-spun ribbon annealed at the same temperature for 1 h, the maximum value of $| ΔS_M |$ reaches 4.5 J $kg^{-1} K^{-1}$. The temperature corresponding to the maximum entropy change increased from 292 K for bulk samples to 295 K for melt-spun ribbons. The lower values of the magnetic entropy change in the melt-spun $LaFe_{11.0}Co_{0.8}(Si_{0.4}Al_{0.6})_{1.2}$ are attributed to the presence of higher volume fraction of the secondary bcc-Fe phase in the ribbon samples.
Źródło:
Acta Physica Polonica A; 2010, 118, 5; 910-912
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Partial Substitution of Fe by Mn on the Thermomagnetic Properties of Magnetocaloric $LaFe_{11.2}Co_{0.7}Si_{1.1}$ Alloy
Autorzy:
Gębara, P.
Marcin, J.
Powiązania:
https://bibliotekanauki.pl/articles/1397028.pdf
Data publikacji:
2018-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Sg
75.50.Bb
Opis:
The aim of this paper was to study the influence of partial substitution of Fe by Mn in the $LaFe_{11.2-x}Mn_{x}Co_{0.7}Si_{1.1}$ (where x=0.1, 0.2 and 0.3) alloys. Measurements revealed that a systematic increase of Mn in the alloy composition resulted in a decrease of the Curie temperature, which correlated with a decrease of the lattice parameter of the La(Fe,Si)₁₃- type phase. For samples corresponding to Mn content x=0.1 and 0.2 a decrease of magnetic entropy change was observed. However in the case of the sample with x=0.3 an increase of magnetic entropy change was detected.
Źródło:
Acta Physica Polonica A; 2018, 133, 3; 648-650
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigations of the Magnetic Phase Transition in the $LaFe_{11.14}Co_{0.66}Si_{1.1}M_{0.1}$ (Where M = Al or Ga) Alloys
Autorzy:
Gębara, P.
Powiązania:
https://bibliotekanauki.pl/articles/1398280.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Sg
75.50.Bb
Opis:
The aim of the present work was to study the phase transition in the $LaFe_{11.14}Co_{0.66}Si_{1.1}M_{0.1}$ (where M = Al or Ga) alloys. Research was carried out using field dependences of magnetization measured at a wide temperature range. Positive slope of the Arrott plots showed that magnetic phase transition in both investigated samples was of second order nature. The temperature dependences of the Landau coefficients also revealed second order phase transition in both specimens. The analysis carried out using universal curve confirmed second nature of phase transition in both samples.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 798-800
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetocaloric Cooling Device with Reciprocating Motion of the Magnetic Field Source
Autorzy:
Kolano, R.
Kolano-Burian, A.
Hreczka, M.
Polak, M.
Szynowski, J.
Tomaka, W.
Powiązania:
https://bibliotekanauki.pl/articles/1398974.pdf
Data publikacji:
2016-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Sg
75.50.Ww
Opis:
This paper describes the magnetic cooling device model designed and built at the Institute of Non-Ferrous Metals in Gliwice, which utilizes reciprocating motion of a magnetic field source and a cyclic flow of a coolant through regenerator. The regenerator made from gadolinum made it possible to obtain an adiabatic temperature change of 2.5 K at the magnetic field of 0.8 T. The magnetic field source was built using neodymium magnets according to our own technology. For the heat transfer, a liquid having the specific heat of about 4000 J/(kg K) has been applied. We have also developed and applied a special driving system enabling reciprocating motion of the magnetic field source and of the pistons in the hot and cold heat exchangers. The tests were made with this cooling model showing that it was possible to obtain, at the frequency of 0.5 Hz, the liquid temperature gradient of 4 K. The potential energy savings resulting from application of this device have been evaluated and compared with the literature data presenting a pre-industrial prototype of the magnetic refrigerator utilizing similar solutions to those applied in our cooling model.
Źródło:
Acta Physica Polonica A; 2016, 129, 6; 1205-1209
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Origin of Magnetic Anisotropy of $Gd_{5}Si_{2}Ge_{2}$ Compound
Autorzy:
Szymczak, R.
Kolano, R.
Kolano-Burian, A.
Hawelek, L.
Krzymanska, B.
Aleshkevich, P.
Dyakonov, V.
Szymczak, H.
Powiązania:
https://bibliotekanauki.pl/articles/1428706.pdf
Data publikacji:
2012-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Gw
75.30.Sg
Opis:
The second-order anisotropy constant $K_2$ in polycrystalline $Gd_5Si_2Ge_2$ giant magnetocaloric material was measured as a function of temperature by the modified singular point detection technique. Although the structural, electrical, thermal, magnetic and magnetocaloric properties of the $Gd_5Si_2Ge_2$ have been rather well investigated experimentally, magnetic anisotropy of this system is almost unknown. The singularity indicating the anisotropy field was determined analyzing ac susceptibility data taking into account several features of the magnetization curve. The temperature dependence of the anisotropy fields was measured from 4.2 K up to the Curie temperature. The observed relationship between $K_2 (T)//K_2$ (0) and magnetization M (T)/M (0) was explained assuming dipolar origin of magnetic anisotropy of $Gd_5Si_2Ge_2$ compound.
Źródło:
Acta Physica Polonica A; 2012, 121, 5-6; 1261-1262
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Ga Addition on Structure and Magnetic Properties of the $LaFe_{11.14}Co_{0.66}Si_{1.2-x}Ga_{x}$ (x=0.1, 0.2, 0.3) Alloys
Autorzy:
Gębara, P.
Pawlik, P.
Michalski, B.
Wysłocki, J.
Kotynia, K.
Powiązania:
https://bibliotekanauki.pl/articles/1402328.pdf
Data publikacji:
2015-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Sg
75.50.Bb
Opis:
In the present work, the phase constitution and magnetic properties of the $LaFe_{11.14}Co_{0.66}Si_{1.2-x}Ga_{x}$ (where x=0.1, 0.2, 0.3) alloys, were investigated. It was revealed that increase of Ga content in the alloy composition causes the rise of lattice parameter of the $La(Fe,Si)_{13}$-type phase, which causes increase of the Curie temperature. However, the increase of Ga addition leads to decrease of magnetocaloric effect.
Źródło:
Acta Physica Polonica A; 2015, 128, 1; 87-90
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetocaloric Effect in Geometrically Frustrated Magnetic Compound $HoB_{12}$
Autorzy:
Snyman, J.
Flachbart, K.
Gabani, S.
Reiffers, M.
Shitsevalova, N.
Siemensmeyer, K.
Strydom, A.
Powiązania:
https://bibliotekanauki.pl/articles/1534216.pdf
Data publikacji:
2010-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Sg
75.40.Cx
Opis:
The magnetocaloric effect of frustrated antiferromagnetic $HoB_{12}$ is calculated. The isothermal entropy change Δ S characterising the magnetocaloric effect shows a small positive change upon magnetisation below the transition temperature $T_{N}$, indicating a small inverse magnetocaloric effect. At $T_{N}$, Δ S shows clear scaling behaviour with the applied magnetic field. The adiabatic temperature change Δ T shows paramagnetic behaviour above $T_{N}$, despite strong magnetic correlations that persist in this temperature region. The adiabatic temperature change calculated for $HoB_{12}$ is appreciable.
Źródło:
Acta Physica Polonica A; 2010, 118, 5; 873-874
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Measurements of Magnetocaloric Effect in $LaFe_{11.14}Co_{0.66}Si_{1.2-x}Al_{x}$ (x=0.1, 0.2, 0.3) Alloys
Autorzy:
Gębara, P.
Pawlik, P.
Michalski, B.
Wysłocki, J.
Powiązania:
https://bibliotekanauki.pl/articles/1387211.pdf
Data publikacji:
2015-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Sg
75.50.Bb
Opis:
In the present work, phase constitution and thermomagnetic properties of $LaFe_{11.14}Co_{0.66}Si_{1.2-x}Al_{x}$ (where x = 0.1, 0.2, 0.3) alloys were investigated. Ingot samples were obtained by arc-melting under the low pressure of Ar atmosphere. Subsequently samples were annealed at 1323 K for 15 days. X-ray diffraction of all samples revealed coexistence of two crystalline phases dominant $La(Fe,Si)_{13}$-type and minor bcc α -Fe. Furthermore, the magnetic measurements at various temperatures allowed to study the Curie temperature, magnetic entropy changes and relative cooling power.
Źródło:
Acta Physica Polonica A; 2015, 127, 2; 576-578
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
About the Role of Fe-Ions in the Formation of Magnetocaloric Effect in $Ho(Co_{1-x}Feₓ)₂$ Compounds
Autorzy:
Anikin, M.
Tarasov, E.
Kudrevatykh, N.
Osadchenko, V.
Zinin, A.
Powiązania:
https://bibliotekanauki.pl/articles/1387987.pdf
Data publikacji:
2015-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Sg
75.50.Gg
Opis:
A study of crystalline structure, magnetic and magnetocaloric properties of $Ho(Co_{1-x}Feₓ)₂$ (x = 0.09, 0.12) intermetallic compounds has been undertaken. Phase composition was controlled by X-ray diffraction analysis. Magnetic properties were measured within the temperature range 4.2-350 K in magnetic fields up to 7 T. Magnetic ordering temperatures corresponding to paramagnetic-ferrimagnetic phase transitions were found to be 199 K and 258 K respectively. Temperature dependences of heat capacity for these compounds have been inferred for the temperature interval 77-340 K. Comparison of magnetocaloric effect (MCE) values determined by direct measurement and by calculation was carried out as well. It was found that significant MCE peak broadening occurs for higher iron concentration in the compound.
Źródło:
Acta Physica Polonica A; 2015, 127, 2; 635-637
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental Study of Magnetocaloric Effect in Dipolar Magnet $KEr(MoO_4)_2$
Autorzy:
Hanko, J.
Orendáč, M.
Kajňaková, M.
Orendáčová, A.
Feher, A.
Powiązania:
https://bibliotekanauki.pl/articles/1813812.pdf
Data publikacji:
2008-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Sg
75.50.Ee
Opis:
We report on magnetothermodynamic properties of single crystal $KEr(MoO_4)_2$ which were investigated from nominally 0.4 K to 20 K in magnetic fields up to 4 T. Using the available specific heat data the diagram of temperature and magnetic field dependence of the total entropy was constructed. Predictions for temperature dependences of the relative temperature variations during the adiabatic demagnetization and the entropy variation during the isothermal demagnetization were calculated from the specific heat data. The obtained results suggest that unlike common refrigerants, in $KEr(MoO_4)_2$ the quantities describing magnetic cooling remain nearly constant in the temperature range 2-10 K.
Źródło:
Acta Physica Polonica A; 2008, 113, 1; 465-468
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Fe addition on the martensitic transformation, structure and magnetic properties of metamagnetic Ni-Co-Mn-Sn alloys
Autorzy:
Wójcik, A.
Maziarz, W.
Szczerba, M.
Sikora, M.
Hawełek, Ł.
Czaja, P.
Powiązania:
https://bibliotekanauki.pl/articles/1154400.pdf
Data publikacji:
2016-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Sg
81.30.Kf
Opis:
In this study the effect of Fe for Ni substitution in Ni₄₄Co₆Mn₃₉Sn₁₁ metamagnetic shape memory alloys on their structure, magneto-structural transformation characteristics, magnetic and magnetocaloric properties was studied. The results show that the structure and martensite transformation behavior strongly depends on the Fe concentration. The martensitic transformation temperature decreases with 1 at.% of Fe and is suppressed with higher Fe content. It was further found that substitution of Fe for Ni leads to lowering of the value of magnetic entropy change.
Źródło:
Acta Physica Polonica A; 2016, 130, 4; 1026-1028
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Properties and Magnetocaloric Effect οf $R_{1-x}R_{x}Mn_{2}Ge_{2}$ Compounds
Autorzy:
Duraj, M.
Szytuła, A.
Powiązania:
https://bibliotekanauki.pl/articles/1538438.pdf
Data publikacji:
2010-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Kz
75.30.Sg
Opis:
The magnetic and magnetocaloric properties of $Sm_{1-x}Gd_{x}Mn_{2}Ge_{2}$ compounds with 0 ≤ x ≤ 0.10 have been studied. $SmMn_{2}Ge_{2}$ is antiferromagnetic below the Néel temperature $T_{N}$ ( ≈ 400 K). Further cooling leeds to canted ferromagnetic phase below $T_C$ = 341 K. With decreasing temperature, two metamagnetic phase transitions are observed: F2-AF1 at $T_2$ = 153 K and AF1-F1 at $T_1$ = 106 K. The maximum values of magnetic entropy change | Δ $S_m$ | are found to be 1.5 J $K^{-1} kg^{-1}$ at $T_{1}$ and 2.0 J $K^{-1} kg^{-1}$ at $T_{2}$ in $SmMn_{2}Ge_{2}$. The MCE is found to increase with Gd concentration, | Δ $S_{m}(T_{1})$ | = 3.3 J $K^{-1} kg^{-1}$, while | Δ $S_{m}(T_{2})$ | is slightly enhanced for x = 0.1. The magnetocaloric effect is found to be positive at $T_{1}$ and negative at $T_{2}$.
Źródło:
Acta Physica Polonica A; 2010, 117, 4; 603-606
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Entropy Change Calculations for Pure Gd and a Ni-Mn-Cu-Ga Heusler Alloy: Constant Field vs. Constant Temperature Experiment
Autorzy:
Ferenc, J.
Kowalczyk, M.
Wróblewski, R.
Cieślak, G.
Sielicki, K.
Leonowicz, M.
Kulik, T.
Powiązania:
https://bibliotekanauki.pl/articles/1402338.pdf
Data publikacji:
2015-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Sg
65.40.gd
Opis:
The magnetocaloric effect may be assessed indirectly by expressing it as the change in magnetic entropy in varying magnetic field, H, as the function of temperature, T. Magnetization, M=f(T,H), may be experimentally acquired from a series of isothermal measurements with variable field, or from a series of constant field measurements with variable temperature. The accuracy of magnetic entropy calculation depends on the number of series in these experiments. The aim of this work is to determine how little data is sufficient to obtain accurate results of magnetic entropy change calculations, on the basis of real, magnetocaloric materials. Pure gadolinium and a Ni-Mn-Cu-Ga Heusler alloy were studied. For both materials, the magnetic entropy change and relative cooling power were calculated from both experiments, with the decreasing number of experimental data. For both materials, the constant field experiment with only 6 field values provided only a 5% error of calculations, as compared to the experiment with 100 field values. The Arrott plots were also drawn for constant field mode with 6 field values, easily indicating the order of transition. Comparison of the calculation results suggests that the constant field mode magnetization measurement may be more accurate and faster than isothermal mode.
Źródło:
Acta Physica Polonica A; 2015, 128, 1; 111-115
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Al and Ga on Formation of the La(Fe,Si)_{13}-Type Phase in the LaFe_{11.14}Co_{0.66}Si_{1.2-x}M_x (where x=0.1, 0.2, 0.3; M=Al, Ga) Alloys
Autorzy:
Gębara, P.
Powiązania:
https://bibliotekanauki.pl/articles/1398815.pdf
Data publikacji:
2016-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Sg
75.50.Bb
Opis:
In the present work the influence of Al and Ga on formation of $La(Fe,Si)_{13}$-type phase in magnetocaloric $LaFe_{11.14}Co_{0.66}Si_{1.2-x}M_x$ (where x=0.1, 0.2, 0.3; M = Al, Ga) alloys subjected to annealing at 1323 K for 15 days was studied using the Mössbauer spectroscopy. For annealed samples, two crystalline phases were recognized: the dominant paramagnetic $La(Fe,Si)_{13}$-type phase, and minor fraction of ferromagnetic α -Fe(Co,Si). It was revealed that Al improved formation of 1:13 phase in contrast to Ga, which caused reduction of the ability of formation of the expected phase.
Źródło:
Acta Physica Polonica A; 2016, 129, 2; 193-196
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental Investigation of Small-Scale Magnetocaloric Refrigerator
Autorzy:
Kaštil, J.
Tětek, J.
Tuček, A.
Powiązania:
https://bibliotekanauki.pl/articles/1399319.pdf
Data publikacji:
2013-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Sg
75.50.Ww
Opis:
The small-scale magnetocaloric cooling device was developed at Czech Technical University in Prague. The magnetocaloric small-scale cooling system was designed as push-pull system with two permanent magnets with field of about 0.85 T. The construction offers a possibility to alter independently many parameters of the cooling process and it ensures easy way to change working material and design of heat exchangers. The measurements were performed with 35 g of gadolinium as a working material and ethanol as heat transfer liquid. Device was successfully operated at room temperature with maximal heat span of 3.1 K. In the article we report design of the machine and first measurement performed on it.
Źródło:
Acta Physica Polonica A; 2013, 124, 4; 740-744
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Influence of Alloy Admixture on Structure and Properties of rm $La(Fe, Co, Si)_{13}$-Type Phase
Autorzy:
Gębara, P.
Pawlik, P.
Škorvánek, I.
Marcin, J.
Wysłocki, J.
Szwaja, M.
Pawlik, K.
Powiązania:
https://bibliotekanauki.pl/articles/1429027.pdf
Data publikacji:
2012-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Sg
75.50.Bb
Opis:
In the present study, the influence of Al and Ga admixture on the lattice parameters and the Curie point $T_{C}$ of the $La(Fe, Co, Si)_{13}$ compound was discussed. The measurements were carried out on ribbon samples of $LaFe_{11.0}Co_{0.8}Si_{1.2},$ $LaFe_{11.0}Co_{0.8}(Si_{0.4}Al_{0.6})_{1.2}$ and $LaFe_{11.0}Co_{0.8}Si_{1.1}Ga_{0.1}$ alloys. The samples were subjected to annealing in the inert gas atmosphere at 1323 K for 24 h. The change of lattice parameters a with admixture of Al and Ga was determined from the X-ray diffraction analysis. Furthermore, changes of the Curie point with the alloy composition were observed.
Źródło:
Acta Physica Polonica A; 2012, 121, 5-6; 1285-1287
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Si Substitution and Annealing on Magnetocaloric Properties in $TbCo_2$
Autorzy:
Janatova, M.
Poltierova Vejpravova, J.
Javorsky, P.
Prokleska, J.
Svoboda, P.
Danis, S.
Powiązania:
https://bibliotekanauki.pl/articles/1813663.pdf
Data publikacji:
2008-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
65.40.Gd
75.30.Sg
Opis:
We report on magnetocaloric properties of the as-cast and annealed $TbCo_2$ with partial substitution of cobalt by silicon. The samples were characterized by powder X-ray diffraction and investigated by heat capacity measurements (8-300 K, in fields 0 T and 1 T). $TbCo_2$ undergoes a second-order type phase transition at $T_C$ = 240 K, from paramagnetic to ferrimagnetic state;similar behavior was revealed in the Si-doped compounds. The temperature dependence of magnetic entropy and the corresponding magnetocaloric effect were derived for all studied samples. The influence of the heat treatment and Si doping on magnetocaloric properties will be discussed in context of the analogue case $Er(Co_{1-x}Si_x)_2$.
Źródło:
Acta Physica Polonica A; 2008, 113, 1; 311-314
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Phase Transitions and Thermal Properties of $Ho(Co_{1-x}Si_x)_2$ Compounds
Autorzy:
Vasylyev, D.
Prokleška, J.
Sechovský, V.
Powiązania:
https://bibliotekanauki.pl/articles/1813682.pdf
Data publikacji:
2008-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Sg
75.50.Gg
Opis:
The specific heat of $HoCo_2$ and $Ho(Co_{0.95}Si_{0.05})_2$ was measured as a function of temperature in several constant magnetic fields up to 8 T. A data analysis allowed us to determine the isothermal entropy change and the magnetocaloric effect in a wide temperature range. The considerable values of the magnetocaloric effect in the vicinity of the magnetic ordering transition are qualifying both compounds as suitable for magnetic refrigeration purposes. The magnetic phase transition temperature $(T_C)$ increases from 77 K for $HoCo_2$ to 103 K for $Ho(Co_{0.95}Si_{0.05})_2$ while the large magnetocaloric effect in the vicinity of TC is maintained, which demonstrates possible ways of tuning the operating temperatures of the magnetic refrigerant.
Źródło:
Acta Physica Polonica A; 2008, 113, 1; 347-350
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetocaloric Study of S=1/2 Low-Dimensional Heisenberg Antiferromagnet $[Cu\text{(phen)}(H_2O)_2]SO_4$
Autorzy:
Sedláková, L.
Orendáč, M.
Kajňaková, M.
Orendáčová, A.
Feher, A.
Powiązania:
https://bibliotekanauki.pl/articles/1813815.pdf
Data publikacji:
2008-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Sg
75.50.Ee
Opis:
We present the experimental study of magnetocaloric effect on powder sample $[Cu\text{(phen)}(H_2O)_2]SO_4$ (phen = phenantroline = $C_{12}H_8N_2$) in the temperature range from nominally 0.2 K to 4 K and in magnetic fields up to 2 T. The values of total entropy were extracted from the experimental data obtained by adiabatic demagnetization. The comparison was performed with the temperature dependence of the entropy for S=1/2 paramagnet calculated at selected magnetic fields. The deviations observed below 0.6 T were attributed to internal field mediated by exchange coupling. In addition, the temperature response observed in $[Cu\text{(phen)}(H_2O)_2]SO_4$ revealed very short relaxation time below 1 K. The comparison of the behavior observed at the end of the demagnetization in $[Cu\text{(phen)}(H_2O)_2]SO_4$ and other systems suggests that the magnetocaloric effect can serve as an alternative tool for studying slow magnetic relaxation.
Źródło:
Acta Physica Polonica A; 2008, 113, 1; 473-476
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Remark about an Analogy between Magnetocaloric Behaviour of Type II Superconductors and Ferromagnetic Materials
Autorzy:
Kalva, Z.
Mánek, P.
Powiązania:
https://bibliotekanauki.pl/articles/2013015.pdf
Data publikacji:
2000-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Sg
74.60.Ge
Opis:
The analogy between magnetocaloric behaviour of type II superconductors and anisotropic ferromagnetic materials is discussed. Special attention is devoted to the influence of anisotropy on the negative magnetocaloric effect near phase transitions.
Źródło:
Acta Physica Polonica A; 2000, 97, 3; 407-410
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermomagnetic Properties of $LaFe_{11.0}Co_{0.8}(Si_{1-x}Al_{x})_{1.2}$ (x=0, 0.6) Alloys
Autorzy:
Gębara, P.
Pawlik, P.
Skorvanek, I.
Marcin, J.
Pawlik, K.
Przybył, A.
Wysłocki, J.
Szwaja, M.
Filipecka, K.
Powiązania:
https://bibliotekanauki.pl/articles/1367677.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Sg
75.50.Bb
Opis:
In the present work, Curie temperature, refrigeration capacity and cooling power of the $LaFe_{11.0}Co_{0.8}(Si_{1-x}Al_{x})_{1.2}$ (where x=0, 0.6) alloys, are investigated. The value of Curie temperature was found to be 280 and 290 K for x=0 and 0.6, respectively. The determined values of cooling power (RCP) and refrigeration capacity (RC) differ only slightly for both investigated alloys. The maximum values of RCP and RC obtained under the change of external magnetic field from 0 to 5 T are 433 J/kg (for x=0) and 290 J/kg (for x=0.6), respectively.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 166-167
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental Study of the Magnetocaloric Effect in the Two-Dimensional Quantum System $Cu(tn)Cl_2$
Autorzy:
Baranová, L.
Tarasenko, R.
Orendáčová, A.
Orendáč, M.
Pavlík, V.
Feher, A.
Powiązania:
https://bibliotekanauki.pl/articles/1368656.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Ee
75.30.Sg
Opis:
Magnetocaloric studies of a two-dimensional antiferromagnet $Cu(tn)Cl_{2}$ (tn=1,3-diaminopropane=$C_3H_{10}N_2)$ have been performed by adiabatic magnetization and demagnetization measurements, in the temperature range from 0.2 to 4 K and magnetic fields up to 2 T. The compound represents an S=1/2 spatially anisotropic triangular-lattice antiferromagnet. The magnetocaloric measurements were focused at the identification of the phase transition to the magnetically ordered state which was not indicated in the previous specific heat studies. Furthermore, the interplay of the magnetic-field induced easy-plane anisotropy and the intrinsic spin anisotropy present in the studied system should manifest in low magnetic fields. The obtained results of the magnetocaloric experiments of $Cu(tn)Cl_{2}$ indicate a double crossover from the normal to inverse magnetocaloric effect (MCE). The first crossover from the normal to inverse MCE occurring at about 0.3 K can be attributed to the competition of the aforementioned anisotropies. The second crossover from the inverse to normal MCE observed at about 2.2 K might be ascribed to the formation of spin vortices stabilized by the easy-plane anisotropy introduced by magnetic field.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 256-257
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetocaloric effect in CsDy(MoO₄)₂
Autorzy:
Tarasenko, R.
Tkáč, V.
Orendáčová, A.
Orendáč, M.
Sechovský, V.
Feher, A.
Powiązania:
https://bibliotekanauki.pl/articles/1050647.pdf
Data publikacji:
2018-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Sg
75.30.Gw
71.70.Ej
Opis:
CsDy(MoO₄)₂ belongs to the family of binary alkaline rare-earth molybdates, with detectable low-temperature structural phase transitions, caused by the cooperative Jahn-Teller effect. Magnetocaloric studies of a single crystal of CsDy(MoO₄)₂ have been performed in the temperature range from 2 K to 18 K in magnetic fields up to 7 T applied along the crystallographic a axis. The maximum value of the isothermal entropy change is about 8 J/(kgK) and was achieved already in the fields above 2 T. The observed results suggest that the studied system can be used as a magnetic refrigerant at helium temperatures.
Źródło:
Acta Physica Polonica A; 2018, 133, 3; 414-416
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Giant Magnetocaloric Effect in Manganites
Autorzy:
Szymczak, R.
Kolano, R.
Kolano-Burian, A.
Dyakonov, V.
Szymczak, H.
Powiązania:
https://bibliotekanauki.pl/articles/1550566.pdf
Data publikacji:
2010-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.47.Lx
75.30.Sg
75.40.Cx
Opis:
In this review we briefly discuss the magnetocaloric properties of the manganites. It is evidenced that the maximum entropy change observed in manganites exceeds that of gadolinium (the prototype material for room temperature refrigerators). For the manganites characterized by second-order magnetic phase transitions the scaling hypothesis is discussed. It is shown that simple phenomenological model with only one fitting parameter, presented in this paper, satisfactorily describes experimental observations.
Źródło:
Acta Physica Polonica A; 2010, 117, 1; 203-206
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetocaloric Effect and Transition Order in $HoAl_{2}$
Autorzy:
Baran, S.
Duraj, R.
Szytuła, A.
Powiązania:
https://bibliotekanauki.pl/articles/1399261.pdf
Data publikacji:
2015-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Cr
75.30.Kz
75.30.Sg
Opis:
Magnetic measurements of $HoAl_{2}$ are reported. The compound crystallizes in the cubic $MgCu_{2}$-type crystal structure. $HoAl_{2}$ exhibits two successive magnetic transitions: below $T_{c}$ = 29 K a ferromagnetic order is formed while anomaly at $T_{t}$ = 20 K is related to reorientation of magnetic moment. Near transition temperatures a magnetocaloric effect with magnetic entropy changes -$ΔS_{m}$ equal to 6.3 J/(mol K) at $T_{c}$ and 5.0 J/(mol K) at $T_{t}$ for an external field $μ_{0}H$ = 9 T is observed.
Źródło:
Acta Physica Polonica A; 2015, 127, 3; 815-817
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetocaloric Effect in $La_{0.8}Sr_{0.2}MnO_{3}$ Film
Autorzy:
Szymczak, R.
Dyakonov, K.
Radelytskyi, I.
Dyakonov, V.
Szymczak, H.
Powiązania:
https://bibliotekanauki.pl/articles/1402317.pdf
Data publikacji:
2015-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Sg
75.47.Lx
75.70.Ak
Opis:
Thin epitaxial film of $La_{0.8}Sr_{0.2}MnO_{3}$ has been deposited on yz-cut $LiNbO_{3}$ by pulsed laser ablation. The film was characterized by X-ray diffraction and magnetic measurements as a single phase. The magnetic properties and the magnetocaloric effect have been measured as a function of magnetic field and temperature. A reasonably high magnetocaloric effect indicates that this film might provide an efficient material for micro magnetic refrigerators.
Źródło:
Acta Physica Polonica A; 2015, 128, 1; 56-58
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Power Losses in $LaFe_{x}Co_{y}Si_{1.1}$ Intermetallics near the Magnetic Phase Transition
Autorzy:
Gozdur, R.
Lebioda, M.
Bernacki, Ł.
Powiązania:
https://bibliotekanauki.pl/articles/1402334.pdf
Data publikacji:
2015-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Sg
75.30.Kz
75.50.Bb
Opis:
The paper presents magnetic parameters of $LaFe_{x}Co_{y}Si_{1.1}$ bulk specimens proving strong magnetocaloric effect. The main research work was oriented on measurements of the alloy's power losses according to IEC 60404 standards and validated with unbalanced bridge method and other methods. The measurements of the $LaFe_{10.8}Co_{1.1}Si_{1.1}$ specimens were determined in the range of temperatures near the Curie temperature where the magnetocaloric effect is the strongest. Power losses were taken into account mainly for the evaluation of usefulness and efficiency in the magnetic refrigeration applications. The results of presented measurements testify that the most suitable range of temperature and the best operational conditions are very close to the point of magnetic phase transition and slightly above it. It indicates that the magnetic state between the $T_{ \Delta S max}$ and $T_{c}$ is more effective for the magnetic refrigeration applications due to lower power losses and high level of the isothermal changes of entropy. Operating temperature below the $T_{ \Delta S max}$ in ferromagnetic state is improper because of the increasing power losses which achieve the level of 130 mJ/kg for main frequency and decrease to 20 mJ/kg for the value of 0.1 Hz.
Źródło:
Acta Physica Polonica A; 2015, 128, 1; 98-103
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Low-Temperature Specific Heat and Magnetocaloric Effect in $RCu_2Ge_2$ (R = Dy-Tm) Compounds
Autorzy:
Gondek, Ł.
Kaczorowski, D.
Pikul, A.
Szytuła, A.
Powiązania:
https://bibliotekanauki.pl/articles/1419609.pdf
Data publikacji:
2012-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.-m
75.30.Sg
75.40.Cx
Opis:
The magnetocaloric effect in $RCu_2Ge_2$ (R = Dy-Tm) was investigated by means of specific heat measurements. The compounds order antiferromagnetically at 6.2 K $(DyCu_2Ge_2),$ 5.6 K $(HoCu_2Ge_2),$ 3.0 K $(ErCu_2Ge_2),$ and 3.9 K $(TmCu_2Ge_2),$ and some of them exhibit additional magnetic transitions in the ordered state. In an external magnetic field the low-temperature specific heat changes significantly, which can be attributed to metamagnetic-like transitions. In this temperature region, the investigated samples show distinctly different magnetocaloric effect.
Źródło:
Acta Physica Polonica A; 2012, 122, 2; 391-393
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Specific Heat of the $Tb_{1-x}La_xNi_2$ Solid Solutions
Autorzy:
Ćwik, J.
Palewski, T.
Nenkov, K.
Powiązania:
https://bibliotekanauki.pl/articles/1813679.pdf
Data publikacji:
2008-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Sg
75.40.-s
74.70.Ad
Opis:
Specific heat measurements have been performed on the polycrystalline $TbNi_2, LaNi_2$ and their solid solutions $Tb_{1-x}La_xNi_2$ (x=0.2, 0.3). The Debye temperatures, phonon and conduction electron contributions as well as the magnetic part of the heat capacity were determined and discussed. The magnetocaloric effect was estimated from measurements performed in a magnetic field of 0.42 T for $TbNi_2,$ $Tb_{0.8}La_{0.2}Ni_2$ and $Tb_{0.7}La_{0.3}Ni_2$.
Źródło:
Acta Physica Polonica A; 2008, 113, 1; 343-346
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Critical Behavior near the Ferromagnetic to Paramagnetic Phase Transition in Y₈Co₆₂B₃₀ Amorphous Alloy
Autorzy:
Śniadecki, Z.
Marcin, J.
Idzikowski, B.
Powiązania:
https://bibliotekanauki.pl/articles/1031033.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.40.Cx
75.50.Kj
75.30.Sg
Opis:
The Y₈Co₆₂B₃₀ amorphous alloy is a collinear ferromagnet. The Arrott plot, the Kouvel-Fisher method, critical isotherm analysis and magnetic field dependence of maximum magnetic entropy changes were the main analytical tools used to determine the nature of the ferromagnetic/paramagnetic phase transition. Values of critical exponents (β, γ, and δ) were calculated and were convergent with those characteristic for mean-field model. It suggests that long range ferromagnetic interactions are playing main role in investigated alloy and the phase transition was confirmed to be of a second order according to the Banerjee criterion.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 967-969
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental Study of the Magnetocaloric Effect in Ni(en)(H₂O)₄SO₄·2H₂O - An S = 1 Molecular Magnet with Easy-Plane Anisotropy
Autorzy:
Tarasenko, R.
Orendáčová, A.
Čižmár, E.
Orendáč, M.
Potočňák, I.
Feher, A.
Powiązania:
https://bibliotekanauki.pl/articles/1032138.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Sg
75.30.Gw
71.70.Ch
Opis:
Magnetocaloric properties of Ni(en)(H₂O)₄SO₄·2H₂O powder were investigated in temperature range from 2 K to 30 K in magnetic fields up to 7 T using isothermal magnetization measurements. The maximum value of the isothermal entropy change in the field 7 T is about 8 J/(kg K), with a refrigerant capacity of 55 J/kg. Temperature dependence of the isothermal entropy change under different magnetic fields is in good agreement with theoretical predictions from crystal electric field parameters.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 904-906
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetocaloric Effect in NiCl₂(bipy) at Low Temperatures
Autorzy:
Ráczová, K.
Čižmár, E.
Feher, A.
Powiązania:
https://bibliotekanauki.pl/articles/1032298.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Sg
75.30.Gw
75.10.Pq
Opis:
Magnetothermal properties of the compound NiCl₂(bipy), where bipy = 4,4'-bipyridine, were studied. The single-ion anisotropy of Ni(II) ions was estimated and its influence on magnetocaloric effect in NiCl₂(bipy) was investigated. Above the metamagnetic transition a maximum in the isothermal change of the magnetic entropy is reached near 11 K at field change from 0T to 7T with peak value -ΔS = 6J K¯¹ kg¯¹. The temperature dependence of ΔS above 7K agrees with the assumed easy-axis type of single-ion anisotropy. The inverse magnetocaloric effect, typical for ordered antiferromagnets, was observed in the ordered state of NiCl₂(bipy) only for isothermal magnetization in small fields up to 2T.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 922-924
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The magnetocaloric effect in {[Cu(bapa)]₃[Cr(CN)₆]₂}ₙ · 6n H₂O at low temperatures
Autorzy:
Ráczová, K.
Vavra, M.
Hegedüs, M.
Čižmár, E.
Powiązania:
https://bibliotekanauki.pl/articles/1048121.pdf
Data publikacji:
2018-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Sg
75.30.Gw
75.10.Pq
Opis:
The crystals of {[Cu(bapa)]₃[Cr(CN)₆]₂}ₙ·6nH₂O (bapa = bis(3-aminopropyl)amine) are formed by infinite Cu(II)-Cr(III) antiparallel chains, which are connected into the third direction by additive [Cu(bapa)] moieties. The onset of long-range magnetic order at 3.2 K was observed by AC susceptibility. The study of the magnetocaloric effect from magnetization measurements yields a large entropy change -ΔS_{M} = 13.65 J K¯¹mol¯¹ (-ΔS_{M} = 12.25 J kg¯¹K¯¹) at the field change from 0 T to 3 T at temperature 4 K. The analysis of the critical behavior of -ΔS_{M} suggests the value of critical exponent n = 0.577 at the ordering temperature characteristic for three-dimensional magnets with Ising anisotropy.
Źródło:
Acta Physica Polonica A; 2018, 133, 3; 429-431
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Scaling of anhysteretic curves for LaFeCoSi alloy near the transition point
Autorzy:
Gozdur, R.
Chwastek, K.
Najgebauer, M.
Lebioda, M.
Bernacki, Ł.
Wodzyński, A.
Powiązania:
https://bibliotekanauki.pl/articles/1053125.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Sg
75.60.-d
75.60.Ej
Opis:
LaFeCoSi alloys have attracted much attention as they exhibit magnetocaloric effect in near room temperature. The paper focuses on the description of anhysteretic curve for LaFeCoSi alloy for temperatures close to transition point. For this purpose the Langevin function is applied. The paper confirms that the Langevin function might be a good starting point for development of analytical models aimed at examination of magnetic properties in La-based magnetocaloric materials.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 801-803
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic and structural studies into the effect of solvent exchange process in metal-organic framework MOF-76(Gd)
Autorzy:
Almáši, M.
Zeleňák, V.
Zeleňáková, A.
Powiązania:
https://bibliotekanauki.pl/articles/1054760.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Sg
75.75.Fk
65.40.gd
Opis:
Effect of solvent exchange/absence on magnetic and structural properties of microporous metal-organic framework MOF-76(Gd) has been performed. Three compounds have been prepared and characterized: as synthesized MOF-76(Gd)-DMF, which containing DMF (N,N'-dimethylformamide) and H₂O molecules in the cavity system, activated complex without solvents, MOF-76(Gd) and water exchanged sample MOF-76(Gd)-H₂O. The structural study showed that compounds undergo structural changes after activation/exchange processes. Changes were mainly observed in the magnetic properties and distances between Gd...Gd ions: 4.718 Å for MOF-76(Gd)-DMF, 4.326 Å for MOF-76(Gd)-H₂O and 4.296 Å for MOF-76(Gd). The magnetic properties of the samples were studied by magnetic susceptibility χ_{M}(T) and magnetization M(H). The low positive value of the Weiss constant, Θ = 1.54 K in compound MOF-76(Gd)-DMF shows on a very weak ferromagnetic interaction. On the contrary, the negative values of Θ in complexes MOF-76(Gd) (-5.58 K) and MOF-76(Gd)-H₂O (-6.23 K) confirm the existence of antiferromagnetic exchange interaction between Gd(III) ions.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 991-993
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Scaling analysis of the magnetocaloric effect in Co/Au nanoparticles
Autorzy:
Hrubovčák, P.
Zeleňáková, A.
Zeleňák, V.
Franco, V.
Powiązania:
https://bibliotekanauki.pl/articles/1054838.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Sg
75.75.Fk
65.40.gd
Opis:
The system of superparamagnetic Co/Au bimetallic nanoparticles of average diameter 7 nm was investigated with respect to its magnetocaloric properties. DC magnetic measurements revealed the presence of field dependent zero field cooled M(T) maximum (6-8 K) and significant zero field cooled/field cooled irreversibility at low temperatures in the system. Documented thermal hysteresis disallow standard magnetic entropy change calculation from isothermal M(H) data, thus we attempted to employ zero field cooled M(T) data for this purpose. Magnetic entropy change was calculated employing the Maxwell relation. In maximal field variation of 1 T relative high magnetic entropy change for nanoparticles Δ S_M ≈ 0.7 J/(kg K) at T =9 K was observed. The data collapsed onto single universal curve after proper axis rescaling.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 795-797
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic properties and flux distribution in the LaFeCoSi/FeCoV hybrid structure
Autorzy:
Gozdur, R.
Lebioda, M.
Najgebauer, M.
Powiązania:
https://bibliotekanauki.pl/articles/1055094.pdf
Data publikacji:
2017-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Sg
75.30.Kz
75.50.Bb
Opis:
The study contains a description of magnetic properties of LaFeCoSi/FeCoV structure. The hybrid structure contains magnetocaloric LaFeCoSi core with high-induction ferromagnetic laminations. The magnetic field inside the magnetic structure is gained by the fringe field from FeCoV laminations. Results of modelling and experimental investigations of modified magnetic properties of LaFeCoSi/FeCoV structure were presented and discussed in the paper.
Źródło:
Acta Physica Polonica A; 2017, 131, 5; 1294-1297
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Production of $LaCaMnO_3$ Composite by Ball Milling
Autorzy:
Gencer, H.
Cengiz, N.
Kolat, V.
Izgi, T.
Atalay, S.
Powiązania:
https://bibliotekanauki.pl/articles/1207685.pdf
Data publikacji:
2014-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.20.Ev
75.47.Lx
75.30.Sg
Opis:
$La_{0.67}Ca_{0.33}MnO_3$ perovskite-type manganite was synthesized by high-energy ball milling raw oxides of $La_2O_3$ (purity 99.9%), $CaCO_3$ (purity > 99%), and MnO (purity > 99%). The ratio of ball and powder weight was 10:1 and the rotating speed was set to 500 rpm. X-ray analysis indicated that $La_{0.67}Ca_{0.33}MnO_3$ single phase was formed completely when milling time is up to 4 h. The peak intensity of perovskite structure decreased and a hump-like peak appeared with further milling time. When the milling time is longer than 40 h, the perovskite structure disappeared and the amorphous phase was formed completely. Scanning electron microscopy picture of 24 h milled sample showed that the particle size generally varies in a broad range from nanometer scale to a few μm. The magnetic measurements showed that ball milling samples have an inhomogeneous magnetic state and exhibit spin-glass like behavior. The significantly small magnetic entropy change and a remarkably broad temperature interval in entropy change were attributed to high degree of structural and magnetic disorder and broadening of magnetic transition.
Źródło:
Acta Physica Polonica A; 2014, 125, 2; 214-216
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Field Induced Unusual Magnetic Behavior at Low Temperature in $Pr_{0.67}Ca_{0.33}MnO_3$
Autorzy:
Pektas, M.
Gencer, H.
Izgi, T.
Kolat, V.
Atalay, S.
Powiązania:
https://bibliotekanauki.pl/articles/1207723.pdf
Data publikacji:
2014-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.47.Lx
75.30.Kz
75.30.Sg
Opis:
In this study, magnetic properties of $Pr_{0.67}Ca_{0.33}MnO_3$ compound were investigated in detail. The magnetization versus temperature (M-T) curve showed that this material undergoes a charge order transition at 200 K. A more pronounced FM phase appeared below 56 K. At T = 5 K, a field induced sharp step like magnetisation transition associated with phase separation was observed. However, after application of 7 T magnetic field at 5 K, the magnetic behaviour of sample was changed completely and full FM behaviour was observed. The more interesting is that the sample remains in the FM state and does not retrieve the initial magnetic state until warmed up to charge order transition temperature. Large negative magnetic entropy change (- 26.18 J/(kg K) at 38 K and 5 T) was attributed to step like magnetisation transition.
Źródło:
Acta Physica Polonica A; 2014, 125, 2; 217-219
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetocaloric Effect in Materials with the First Order Transitions - Direct Measurements
Autorzy:
Kamarád, J.
Kaštil, J.
Arnold, Z.
Javorský, P.
Sechovský, V.
Powiązania:
https://bibliotekanauki.pl/articles/1535138.pdf
Data publikacji:
2010-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Sg
75.30.Kz
75.50.Cc
Opis:
The results of direct measurements of the magneto-caloric characteristics Δ $T_{ad}$ and the indirect determination of Δ $S_{m}$ of pure Gd around the Curie temperature and of the $FeMnP_{0.45}As_{0.55}$ and $Ni_{45}Co_5Mn_{31}Ga_{19}$ intermetallics in the vicinity of the first order magnetic and structural phase transitions are presented and discussed. A pronounced temperature and field dependence of the first order transitions in the studied materials manifests restrictions applying these materials in magnetic refrigeration techniques. An effective use of the Ericsson and the Brayton refrigeration cycles with $FeMnP_{0.45}As_{0.55}$ in the role of a refrigerant is discussed.
Źródło:
Acta Physica Polonica A; 2010, 118, 5; 1000-1001
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Anisotropy of the Magnetocaloric Effect in the $Ni_{49.6}Mn_{27.6}Ga_{22.8}$ Single Crystal
Autorzy:
Wroblewski, R.
Sielicki, K.
Leonowicz, M.
Powiązania:
https://bibliotekanauki.pl/articles/1402315.pdf
Data publikacji:
2015-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
65.40.gd
75.30.Gw
75.30.Sg
Opis:
The magnetocaloric effect anisotropy in the $Ni_{49.6}Mn_{27.6}Ga_{22.8}$ single crystal was investigated. In the examined alloy the structural phase transition and magnetic transition occur at room temperature and around 370 K, respectively. The magnetic entropy change, at those two temperatures, was determined on the basis of isothermal and isofield curves, recorded at fields up to 1200 kA/m (1.5 T) with temperature steps of 2.5 and 5 K. Although the calculated values of magnetic entropy change are relatively small, ≈0.7 J/(kg K), an anisotropy of the magnetocaloric effect is observed with a magnetic field applied along the main crystallographic directions of the single crystal. The magnetic entropy change at the structural phase transition depends on the orientation. The weakest magnetocaloric effect occurs when the field is applied along [1 0 0] direction whereas the highest magnetocaloric effect value is reached along [0 0 1] direction, which is an easy magnetization axis. Such behaviour can be explained with the high magnetocrystalline anisotropy of the martensitic phase. The magnetic entropy change value, at the structural phase transition, obtained for the polycrystalline specimen, is close to that for the [0 0 1] single crystal direction.
Źródło:
Acta Physica Polonica A; 2015, 128, 1; 54-55
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Nonstoichiometry on Magnetocaloric Effect in $(La_{0.7}Ca_{0.3})_{1 - x}Mn_{1+x}O_3$
Autorzy:
Sazanovich, A.
Pietosa, J.
Pashchenko, A.
Zubov, E.
Dyakonov, V.
Szymczak, H.
Powiązania:
https://bibliotekanauki.pl/articles/1419814.pdf
Data publikacji:
2012-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Sg
61.50.Nw
65.40.gd
Opis:
Magnetocaloric effect in $(La_{0.7}Ca_{0.3})_{1 - x}Mn_{1 + x}O_3$ manganites with x = 0, 0.1, 0.2 has been investigated. It is found a strong influence of nonstoichiometry caused by excessive manganese on the magnetic entropy change. The magnetocaloric effect was evaluated from the isothermal curves of spontaneous magnetization versus the applied magnetic field by using the well-known thermodynamical Maxwell relation. The maximum entropy value, $| \Delta S_{M}^\text{max} |,$ near the ferromagnetic-paramagnetic phase transition is shown to increase with the manganese content. The $La_{0.56}Ca_{0.24}Mn_{1.2}O_3$ manganite exhibits the largest $| \Delta S_{M}^\text{max} |$ value equal to $3.09 J kg^{-1} K^{-1}$ at 15 kOe near $T_{C}$ = 267 K. The magnetocaloric effect values obtained allow to propose that the studied manganites are promising materials for future cooling application.
Źródło:
Acta Physica Polonica A; 2012, 122, 1; 162-166
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetocaloric Properties of Severe Plastic Deformed $Gd_{100-x}Y_x$ Alloys
Autorzy:
Taskaev, S.
Skokov, K.
Karpenkov, D.
Khovaylo, V.
Buchelnikov, V.
Zherebtsov, D.
Ulyanov, M.
Bataev, D.
Drobosyuk, M.
Pellenen, A.
Powiązania:
https://bibliotekanauki.pl/articles/1388004.pdf
Data publikacji:
2015-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Sg
75.30.Gw
75.50.Cc
Opis:
In this work we report on the results of investigation of the magnetocaloric effect in $Gd_{100-x}Y_x$ (x = 0, 5, 10, 15) cold rolled ribbons. It is shown that the magnetocaloric effect exists within a wide temperature interval 258-295 K and is comparable with magnetocaloric effect observed in bulk samples of pure gadolinium. The value of the magnetocaloric effect in the rolled samples is reduced as compared with the bulk samples and strongly depends on the degree of the plastic deformation. Heat treatment procedures can restore the values of the magnetocaloric effect in the cold rolled ribbons up to initial ones. Thus, cold rolling is proposed to be a promising technique for producing thin forms of magnetocaloric materials for heat exchangers of magnetic cooling devices, modifying microstructure of the materials and related magnetic properties.
Źródło:
Acta Physica Polonica A; 2015, 127, 2; 641-643
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Charge-Ordering and Magnetoelastic Coupling Effects on the Magnetocaloric Properties of Manganites
Autorzy:
Reis, M. S.
Gomes, A. M.
Araújo, J. P.
Tavares, P. B.
Amaral, J. S.
Oliveira, I. S.
Amaral, V. S.
Powiązania:
https://bibliotekanauki.pl/articles/2037124.pdf
Data publikacji:
2004
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Sg
75.30.Kz
75.80.+q
Opis:
A study of the magnetocaloric properties of La$\text{}_{1-x-y}$Y$\text{}_{y}$Ca$\text{}_{x}$MnO$\text{}_{3}$, La$\text{}_{1-x}$Cd$\text{}_{x}$MnO$\text{}_{3}$, and Pr$\text{}_{1-x}$Ca$\text{}_{x}$MnO$\text{}_{3}$ manganites with ferromagnetic and charge-ordered states is presented. The ferromagnetic lanthanum manganites show a negative entropy change peakΔ S under the application of a magnetic field at the Curie temperature. However, the magnetoelastic coupling effects lead to a first-order paramagnetic-ferromagn etic transition and an increasedΔ S compared to simple ferromagnets. This effect is analyzed in the framework of the Landau theory of phase transitions which shows a comparable influence of the magnetoelastic couplings and the ordinary magnetic ordering effect. The Pr$\text{}_{1-x}$Ca$\text{}_{x}$MnO $\text{}_{3}$ system shows a rich electric and magnetic phase diagram, with a ferromagnetic insulator phase for 0.15
Źródło:
Acta Physica Polonica A; 2004, 105, 1-2; 163-171
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermodynamic Properties of Geometrically Frustrated S=1/2 XY Antiferromagnet $Er_{2}Sn_{2}O_{7}$
Autorzy:
Al Ghamdi, N.
Orendáčová, A.
Pavlík, V.
Orendáč, M.
Powiązania:
https://bibliotekanauki.pl/articles/1368676.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.10.Dg
75.50.Ee
75.30.Sg
Opis:
The magnetic susceptibility, specific heat and entropy of geometrically frustrated S=1/2 XY antiferromagnet $Er_{2}Sn_{2}O_{7}$ are reported. It is shown, that temperature dependence of magnetic susceptibility above nominally 10 K is governed by crystal field effects. Systematic study of specific heat in magnetic fields up to 7 T enabled the estimation of exchange coupling, J/k<<4.6 K. Investigation of isothermal change of magnetic entropy upon magnetization from 1 T to 7 T revealed the absence of enhanced magnetocaloric effect. The obtained results suggest that frustration parameter f ≈140 proposed for $Er_{2}Sn_{2}O_{7}$ earlier may be significantly overestimated.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 264-265
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Large Magnetocaloric Effect in $Nd_{2}Ni_{2}In$
Autorzy:
Maskova, S.
Danis, S.
Llobet, A.
Nakotte, H.
Havela, L.
Powiązania:
https://bibliotekanauki.pl/articles/1368761.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Ee
75.30.Kz
75.30.Sg
Opis:
$Nd_{2}Ni_{2}In$ is an antiferromagnet ($T_{N}$=8 K) with crystal structure equivalent to the Shastry-Sutherland lattice, possibly leading to the magnetic frustration. The AF coupling with moments in the basal plane can be driven by weak magnetic fields (<0.2 T) into the c-axis ferromagnet. The situation leads to large changes of magnetic entropy in fields below 1 T, which makes $Nd_{2}Ni_{2}In$ a candidate for magnetocaloric applications. The entropy change is 9.6 J/(kg K) in fields of 1 T.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 282-283
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Anomalous Magnetocaloric Properties of the Spin-1/2 Ising Model on a Decorated Square Lattice in a Vicinity of Second-Order Phase Transition
Autorzy:
Karľová, K.
Strečka, J.
Powiązania:
https://bibliotekanauki.pl/articles/1032487.pdf
Data publikacji:
2017-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.10.Hk
75.30.Sg
75.40.-s
75.50.Cc
Opis:
Magnetocaloric properties of the spin-1/2 Ising model on a decorated square lattice in a transverse magnetic field are investigated by the use of a generalized decoration-iteration transformation, which establishes a rigorous mapping correspondence with the zero-field spin-1/2 Ising model on a square lattice. The temperature dependence of the entropy, the isothermal entropy change and the adiabatic temperature change display anomalous singular behavior in a vicinity of a second-order phase transition. The large inverse magnetocaloric effect can be found in the isothermal entropy change within the temperature interval, which is delimited by the critical temperatures at zero and non-zero transverse fields.
Źródło:
Acta Physica Polonica A; 2017, 132, 1; 170-172
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Properties of Ion Irradiated Fe₇₅Mo₈Cu₁B₁₆ Metallic Glass
Autorzy:
Hasiak, M.
Miglierini, M.
Powiązania:
https://bibliotekanauki.pl/articles/1032745.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Kj
75.60.Ej
75.30.Sg
76.80.+y
Opis:
Microstructure and thermomagnetic properties of ion-bombarded amorphous Fe₇₅Mo₈Cu₁B₁₆ alloy are investigated. The Mössbauer spectroscopy shows that surface regions at the air side of the ribbons irradiated with 2×10¹⁶ ions/cm² were significantly affected by 130 keV N⁺ ions. On the other hand, the opposite (wheel) side that was not exposed to ion irradiation is practically intact. The analysis of temperature dependences of magnetization shows the Curie points of 313 K and 316 K for as-quenched and irradiated samples, respectively. The maximum of magnetic entropy change calculated for the irradiated alloy in a magnetic field of 1.0 T occurs at 312.5 K and equals to 0.77 J kg¯¹ K¯¹ while that of the as-quenched sample is 0.74 J kg¯¹ K¯¹.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 768-770
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Inverse magnetocaloric effect in spin-1/2 Fishers super-exchange antiferromagnet
Autorzy:
Gálisová, L.
Strečka, J.
Powiązania:
https://bibliotekanauki.pl/articles/1052954.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.50.+q
75.30.Et
75.30.Sg
75.30.Kz
Opis:
The isothermal entropy change and the adiabatic temperature change are rigorously calculated for the exactly solved spin-1/2 Fisher's super-exchange antiferromagnet in order to examine magnetocaloric properties of the model in a vicinity of the second-order phase transition. It is shown that the large inverse magnetocaloric effect occurs around the temperature interval T_c(h≠0) < T < T_c(h=0) for any magnetic-field change Δh:0 → h. The most pronounced inverse magnetocaloric effect can be found for the magnetic-field change, which coincides with the critical field of a zero-temperature phase transition from the antiferromagnetically ordered ground state to the paramagnetic one.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 627-629
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetocaloric effect in Gd₂O₃@SiO₂ nanocomposite
Autorzy:
Zeleňáková, A.
Hrubovčák, P.
Berkutova, A.
Kapusta, O.
Zeleňák, V.
Powiązania:
https://bibliotekanauki.pl/articles/1054708.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Sg
81.05.Rm
75.20.Ck
75.75.Fk
Opis:
Nanocomposite consisting of Gd₂O₃ nanoparticles embedded in periodical porous silica matrix was investigated with respect to its magnetocaloric properties. Series of field (up to 5 T) dependence of magnetization data were recorded in temperature range 2-52 K. The data were subsequently processed employing Maxwell relation in order to calculate magnetic entropy change (Δ S_M) of the system. Examined nanocomposite exhibited reasonably high value of Δ S_M ≈ 29 J/(kg K) at maximal field change 5 T at the temperature of 2 K which suggests that this material could be feasible for cryomagnetic refrigeration applications.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 810-812
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Enhanced magnetocaloric effect due to selective dilution in a triangular ising antiferromagnet
Autorzy:
Borovský, M.
Žukovič, M.
Powiązania:
https://bibliotekanauki.pl/articles/1054817.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.50.+q
75.50.Ee
75.30.Sg
05.10.Ln
Opis:
We employ an effective-field theory with correlations in order to study a magnetocaloric effect on a triangular Ising antiferromagnet, which is selectively diluted by non-magnetic impurities on one of the three sublattices. Such a dilution generally relieves massive degeneracy in our system and therefore the ground-state entropy diminishes and the magnetocaloric effect weakens at low temperatures. However, at relatively higher temperatures we can observe significantly enhanced negative isothermal entropy changes for the sublattice concentration p_A=0.8.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 645-647
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Substitution and Milling on Structural and Magnetic Properties of Selected $Sm(Ni_{1-x}Co_{x})₃$ Compounds
Autorzy:
Sikora, M.
Blachliński, D.
Ociepka, K.
Prusik, K.
Bajorek, A.
Chełkowska, G.
Powiązania:
https://bibliotekanauki.pl/articles/1397029.pdf
Data publikacji:
2018-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Cr
75.30.Sg
75.50.Gg
75.50.Vv
Opis:
The influence of substitution of Co for Ni in $Sm(Ni_{1-x}Co_{x})₃$, where x=0.0, 0,1, 0.2, on the structural and magnetic properties has been investigated. Samples with x= 0.0 and 0.2 were subjected to grinding in a high energy ball mill. The presence of a PuNi₃ type of crystal phase was evidenced for bulk crystalline and powders specimens. With an increase in the cobalt content, an increase at T_{c} was observed. From the magnetic isotherms, the magnetic entropy changes were determined both for solid and powdered samples. It has been shown that the value of the magnetic entropy change at T_c is doubled for the bulk sample with x= 0.2 but it has decreased significantly for all powdered samples.
Źródło:
Acta Physica Polonica A; 2018, 133, 3; 486-488
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Structural and Thermomagnetic Properties of $Fe_{86-x}Zr₇M_xNb_2Cu_1B_4$ (M = Co, Ni, (CoCr); x=0 or 6) Amorphous Alloys
Autorzy:
Łukiewska, A.
Powiązania:
https://bibliotekanauki.pl/articles/1398268.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
65.60.+a
75.50.Kj
75.50.Bb
75.30.Sg
Opis:
The effect of the substitution of Co, Ni or (CoCr) for the part of Fe atoms on the thermal stability and some magnetic properties, i.e. magnetization and magnetocaloric effect of $Fe_{86-x}Zr₇M_xNb_2Cu_1B_4$ (M = Co, Ni, (CoCr); x=0 or 6) alloys was investigated. From X-ray studies it was stated that the investigated alloys in the as-quenched state and after the accumulative annealing for 10 min at 600 K and then 700 K were fully amorphous. The amorphous as-quenched $Fe_{80}Zr_7Ni_6Nb_2Cu_1B_4$ alloy shows the lowest thermal stability and the onset of its crystallization temperature is equal to 775 K. The Arrott plots are almost linear and show positive slope near the Curie temperature. The maximum magnetic entropy change is very sensitive to the chemical composition and annealing conditions of the alloys.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 738-740
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Systems at Criticality: Different Signatures of Scaling
Autorzy:
Pełka, R.
Konieczny, P.
Fitta, M.
Czapla, M.
Zieliński, P.
Bałanda, M.
Wasiutyński, T.
Miyazaki, Y.
Inaba, A.
Pinkowicz, D.
Sieklucka, B.
Powiązania:
https://bibliotekanauki.pl/articles/1399023.pdf
Data publikacji:
2013-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.40.-s
75.30.Kz
75.30.Sg
75.50.Xx
Opis:
Different aspects of critical behaviour of magnetic materials are presented and discussed. The scaling ideas are shown to arise in the context of purely magnetic properties as well as in that of thermal properties as demonstrated by magnetocaloric effect or combined scaling of excess entropy and order parameter. Two non-standard approaches to scaling phenomena are described. The presented concepts are exemplified by experimental data gathered on four representatives of molecular magnets.
Źródło:
Acta Physica Polonica A; 2013, 124, 6; 977-989
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Low Temperature Magnetic Properties of $Pr_{0.7}(Ca,Sr)_{0.3}CoO_{3}$ Oxides
Autorzy:
Deac, I.
Vlădescu, A.
Balasz, I.
Tunyagi, A.
Tetean, R.
Powiązania:
https://bibliotekanauki.pl/articles/1503539.pdf
Data publikacji:
2011-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.47.Lx
75.30.Kz
75.30.Sg
73.43.Qt
Opis:
We have investigated magnetic and magnetocaloric properties of $Pr_{0.7}(Ca_{1-x}Sr_{x})_{0.3}CoO_{3},$ when the average size of the interpolated cation was changed. $Pr_{0.7}Ca_{0.3}CoO_{3}$ has an orthorhombic Pnma symmetry and it shows a magnetic cluster-glass behavior below 70 K. When Sr partially replaces Ca in this compound, its magnetic properties are improved, and it begins to have ferromagnetic-like behavior. The magnetic transition temperature, gradually, increases with increasing Sr content, up to 170 K, for x=1. The electrical conduction also improved when Sr content increased. All the samples show negative magnetoresitance. Magnetic entropy change $\Delta S_{M}$ was estimated from isothermal magnetization data. We have found that it had higher values for the samples with x>0.5, around 1 J/kg K for Δ B=4 T, with reasonable good relative cooling power.
Źródło:
Acta Physica Polonica A; 2011, 120, 2; 306-310
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetocaloric Properties of Fe₇₅Mo₈Cu₁B₁₆ and Fe₈₁Mo₈Cu₁B₁₀ Metallic Glasses
Autorzy:
Hasiak, M.
Miglierini, M.
Kaleta, J.
Bujdoš, M.
Powiązania:
https://bibliotekanauki.pl/articles/1387599.pdf
Data publikacji:
2015-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Sg
71.23.Cq
76.80.+y
87.64.Pj
Opis:
Microstructure and thermomagnetic properties for the Fe₇₅Mo₈Cu₁B₁₆ and Fe₈₁Mo₈Cu₁B₁₀ metallic glasses in the as-quenched state and after heat treatment at 643 K and 723 K are studied. The inverse change of the Curie point was observed for Fe₇₅Mo₈Cu₁B₁₆ metallic glass after annealing below the onset of crystallization. It is attributed to structural relaxation of the amorphous phase. The maximum of magnetic entropy change calculated for magnetic field of 1.0 T occurs for the Fe₇₅Mo₈Cu₁B₁₆ alloy annealed at 643 K at temperature close to the Curie point and equals 0.74 J kg¯¹ K¯¹.
Źródło:
Acta Physica Polonica A; 2015, 127, 2; 608-610
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Isothermal Entropy Change and Adiabatic Change of Temperature of the Antiferromagnetic Spin-1/2 Ising Octahedron and Dodecahedron
Autorzy:
Karľová, K.
Strečka, J.
Madaras, T.
Powiązania:
https://bibliotekanauki.pl/articles/1032208.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Sg
75.10.Hk
75.50.Ee
75.50.Xx
Opis:
The spin-1/2 Ising octahedron and dodecahedron with a unique antiferromagnetic interaction display an outstanding magnetization jump at zero magnetic field, which consequently leads to a giant magnetocaloric effect during the adiabatic demagnetization. In the present work we report temperature dependences of two basic magnetocaloric response functions: the isothermal entropy change and the adiabatic change of temperature. It is shown that the Ising octahedron and dodecahedron generally exhibit a large negative isothermal entropy change upon increase of the magnetic field, which serves in evidence of their cooling performance.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 630-632
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetocaloric effect in amorphous and partially crystallized Fe₈₀Zr₇Cr₆Nb₂Cu₁B₄ alloy
Autorzy:
Łukiewska, A.
Olszewski, J.
Hasiak, M.
Gębara, P.
Powiązania:
https://bibliotekanauki.pl/articles/1047599.pdf
Data publikacji:
2018-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
65.60.+a
75.50.Kj
75.50.Bb
75.30.Sg
Opis:
In the present work the microstructure and thermomagnetic properties of Fe₈₀Zr₇Cr₆Nb₂Cu₁B₄ ribbon in the as-quenched state and after the accumulative annealing in the temperature range 600-800 K for 10 min were studied using Mössbauer spectroscopy and vibrating sample magnetometry. The second order phase transition from ferro- to paramagnetic state is observed. The Curie temperature T_{C} defined as inflection point on the magnetization versus temperature curve recorded on zero-field cooled mode equals 262.5 K for the as-quenched material. With increasing the annealing temperature increase of T_{C} is observed. The maximum value of the magnetic entropy change (-ΔS) observed in the vicinity of the Curie point is equal to 0.85 J/(kg K) for the alloy in the as-quenched state. Moreover, for the samples annealed up to 750 K for 10 min the low intensity maximum at about 190 K related to the supplementary magnetic phase is observed. The presence of this phase was confirmed as additional component visible on hyperfine field distributions of Mössbauer spectra.
Źródło:
Acta Physica Polonica A; 2018, 133, 3; 676-679
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic and Structural Study of $Mn_{1.15}Fe_{0.85}P_{1-x}Ge_{x}$ (0.25 < x < 0.32) Magnetocaloric Compounds Prepared by Arc Melting
Autorzy:
Hawelek, L.
Wlodarczyk, P.
Zackiewicz, P.
Polak, M.
Kaminska, M.
Puźniak, R.
Radelytskyi, I.
Kolano-Burian, A.
Powiązania:
https://bibliotekanauki.pl/articles/1402326.pdf
Data publikacji:
2015-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Sg
75.30.Kz
61.05.C-
61.66.Fn
Opis:
Recently, room temperature magnetocaloric materials increasingly attracted attention in the development of magnetic refrigerators. In this paper, an effect of P/Ge substitution on the magnetic phase transition in the series of $Mn_{1.15}Fe_{0.85}P_{1-x}Ge_{x}$ (0.25 < x < 0.32) magnetocaloric compounds prepared by the arc melting technique and subsequent homogenization process has been studied. Calorimetric and magnetization results show that the temperature of structural phase transition coincide with the Curie temperature and fall within the temperature range 270-355 K. The magnetic entropy change reaches the maximum value for the compound with x=0.28 and equals to 32 J/(kg K) for the magnetic field change of 5 T. The adiabatic temperature change for the same sample, measured using magnetocalorimeter, is equal to 1.2 K for the magnetic field change of 1.7 T. It was found that the increase of Ge content in the sample causes weakening of first order magnetic transition, which is manifested by the lowering difference in transition temperature measured in two zero-field-cooling and field-cooled-cooling regimes.
Źródło:
Acta Physica Polonica A; 2015, 128, 1; 76-80
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetocaloric Effect in $NdNi_4Si$ Compound
Autorzy:
Falkowski, M.
Toliński, T.
Kowalczyk, A.
Powiązania:
https://bibliotekanauki.pl/articles/1429061.pdf
Data publikacji:
2012-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Sg
75.30.Kz
75.47.Np
75.40.-s
Opis:
On the basis of the thermodynamic approach, we report the magnetocaloric properties of the ternary ferromagnetic $NdNi_4Si$ compound with magnetic phase transition temperature $T_{C}$ at 8 K. The saturated magnetic moment in H = 9 T is equal to 1.5 $μ_{B}$/f.u. at 4.2 K and the compound crystallizes in the hexagonal $CaCu_5$-type structure (space group P6/mmm). The magnetocaloric effect was calculated in terms of the isothermal magnetic entropy change Δ $S_{M}$ as well as the adiabatic temperature change Δ $T_{ad}$ using the specific heat data and magnetization measurements. Within the second order phase transition significant values of these parameters have been observed.
Źródło:
Acta Physica Polonica A; 2012, 121, 5-6; 1290-1292
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ground State, Magnetization Process, and Magnetocaloric Effect of the Exactly Tractable Spin-Electron Tetrahedral Chain
Autorzy:
Gálisová, L.
Strečka, J.
Powiązania:
https://bibliotekanauki.pl/articles/1384829.pdf
Data publikacji:
2015-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.10.Pq
75.60.Ej
75.30.Sg
05.50.+q
Opis:
A hybrid spin-electron system on one-dimensional tetrahedral chain, in which the localized Ising spin regularly alternates with the mobile electron delocalized over three lattice sites, is exactly investigated using the generalized decoration-iteration transformation. The system exhibits either the ferromagnetic or antiferromagnetic ground state depending on whether the ferromagnetic or antiferromagnetic interaction between the Ising spins and mobile electrons is considered. The enhanced magnetocaloric effect during the adiabatic demagnetization suggests a potential use of the investigated system for low-temperature magnetic refrigeration.
Źródło:
Acta Physica Polonica A; 2015, 127, 2; 216-218
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Grain-Size Effect on the Magnetocaloric Properties of the $DyCo_{3}B_{2}$ Compound
Autorzy:
Toliński, T.
Synoradzki, K.
Powiązania:
https://bibliotekanauki.pl/articles/1367515.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.20.Lp
75.30.Sg
75.40.Cx
81.20.Ev
Opis:
The compound $DyCo_{3}B_{2}$ has been recently found to show a significant magnetocaloric effect (MCE) at the ferromagnetic ordering temperature $T_{C}$=22 K. In the present study we verify the influence of the mechanical milling, i.e. the grains size effect on the characteristic parameters describing MCE. The grain size has been determined after each milling time by X-ray diffraction. MCE has been extracted from both the isothermal magnetization and the specific heat measurements. It is found that even a long milling does not spoil significantly the MCE parameters and only $t_{m}$>5 h reduces noticeably the value of the magnetic susceptibility, the isothermal magnetic entropy change and the relative cooling power.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 160-161
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Properties and Magnetocaloric Effect of $DyNi_{4}Si$
Autorzy:
Synoradzki, K.
Kowalski, W.
Falkowski, M.
Toliński, T.
Kowalczyk, A.
Powiązania:
https://bibliotekanauki.pl/articles/1367640.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.20.Lp
75.30.Sg
75.40.Cx
81.20.Ev
Opis:
The magnetic properties and magnetocaloric effect (MCE) in $DyNi_{4}Si$ have been studied by the magnetization and specific heat measurements. The saturation magnetic moment in $μ_{0}H$=9 T is equal to 7.9 $μ_{B}$/f.u at 4.2 K. A significant MCE has been observed around the second order phase transition at $T_{C}$=11 K. The maximum magnetic entropy change is -Δ $S_{M}$=14.5 J $kg^{-1}K^{-1}$ for the magnetic field change of 9 T.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 162-163
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cywil w mundurze
Autorzy:
Bączyk, Norbert.
Kucharczyk, Krzysztof.
Powiązania:
Polska Zbrojna 2007, nr 45, s. 21-22
Data publikacji:
2007
Tematy:
Sztab Generalny WP. Oddział Identyfikacji Bojowej i Normalizacji Operacyjnej SG WP.
Zarząd Planowania Systemów Dowodzenia Łączności SG WP.
GPS.
Łączność wojskowa satelitarna system
System łączności satelitarny.
Systemy satelitarne
System pozycjonowania globalny.
Opis:
Zawiera : Trzy pytania do ppłk. mgr. inż. Krzysztofa Kucharczyka.
Fot.
Dostawca treści:
Bibliografia CBW
Artykuł
Tytuł:
"Wojny pamięci": historia, polityka i służby specjalne Federacji Rosyjskiej
"Memory wars": history, politics and special services of the Russian Federation
Autorzy:
Darczewska, Jolanta
Powiązania:
https://bibliotekanauki.pl/articles/501579.pdf
Data publikacji:
2019-04-23
Wydawca:
Agencja Bezpieczeństwa Wewnętrznego
Tematy:
polityka historyczna
polityka pamięci
historia służb specjalnych
walka informacyjna
Oddział II SG WP
techniki manipulacyjne
historical policy 
memory policy
history of special services
information struggle
Section II SG WP
manipulation techniques
Opis:
„Wojny pamięci” wyznaczają rosyjską specyfikę problematyki określanej na Zachodzie jako „polityka historyczna” bądź „polityka pamięci”. Argumenty historyczne, wpisane w FR w kontekst wojen informacyjnych i kulturowych oraz utożsamiane z psychologiczną wojną interpretacyjną dziejów, służą do realizacji celów politycznych na arenie wewnętrznej i zewnętrznej: wizje sprzeczne z oficjalną są dyskredytowane jako antyrosyjskie i falsyfikujące historię Rosji. Tekst składa się z trzech części. W pierwszej omówiono ewolucję problemu w rosyjskim dyskursie publicznym po rozpadzie ZSRR, ze szczególnym uwzględnieniem historiografii resortowej nadającej kierunek walce informacyjnej z historią w tle. W części drugiej pokazano miejsce rosyjskich służb specjalnych w praktyce prowadzenia tej walki, a także jej przejawy na płaszczyźnie kulturowej, strukturalnej i wydarzeniowej. W części trzeciej przedstawiono wizję historycznych relacji polsko- -rosyjskich w optyce historiografii FR. Jest to wizja konfrontacyjna, zorientowana na budowanie napięć. Legła ona także u podstaw tzw. rosyjskiego standardu historyczno- kulturowego (wzorca obligatoryjnych diagnoz, ocen i interpretacji historycznych), w związku z czym należy ją rozpatrywać zarówno w wymiarze taktycznym, jak i strategicznym.
“Memory wars” determine the topic described in the West as “historical politics” or “memory politics”. Historical arguments, put in Russian Federation into a context of information and cultural wars and identified with psychological war of history interpretation, are aimed to realize political goals in the country and outside: visions contradictory to the official one are discredited as anti-Russian and as falsifying Russian history. The text consists of three parts. First part describes the problem evolution in Russian public discussions after the USSR collapse with the particular consideration of the departmental historiography guiding the information fight with history in the background. The second part presents the role of Russian special services in the practical fight and their symptoms in cultural, structural areas. The third part presents a vision of historical Polish and Russian relations in view of the Russian historians. It is a confrontation vision, oriented towards building tensions. It is behind the so called Russian historical and cultural standard (a model of obligatory diagnosis, assessments and historical interpretations) and as such it should be regarded in tactical as well as in strategic dimensions. 54
Źródło:
Przegląd Bezpieczeństwa Wewnętrznego; 2019, 11, 20; 13-41
2080-1335
2720-0841
Pojawia się w:
Przegląd Bezpieczeństwa Wewnętrznego
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
"Memory wars": history, politics and special services of the Russian Federation
„Wojny pamięci”: historia, polityka i służby specjalne Federacji Rosyjskiej
Autorzy:
Darczewska, Jolanta
Powiązania:
https://bibliotekanauki.pl/articles/501856.pdf
Data publikacji:
2019-04-23
Wydawca:
Agencja Bezpieczeństwa Wewnętrznego
Tematy:
historical policy
memory policy
history of special services
information struggle
Section II SG WP
manipulation techniques
polityka historyczna
polityka pamięci
historia służb specjalnych
walka informacyjna
Oddział II SG WP
techniki manipulacyjne
Opis:
“Memory wars” determine the topic described in the West as “historical politics” or “memory politics”. Historical arguments, put in Russian Federation into a context of information and cultural wars and identified with psychological war of history interpretation, are aimed to realize political goals in the country and outside: visions contradictory to the official one are discredited as anti-Russian and as falsifying Russian history. The text consists of three parts. First part describes the problem evolution in Russian public discussions after the USSR collapse with the particular consideration of the departmental historiography guiding the information fight with history in the background. The second part presents the role of Russian special services in the practical fight and their symptoms in cultural, structural areas. The third part presents a vision of historical Polish and Russian relations in view of the Russian historians. It is a confrontation vision, oriented towards building tensions. It is behind the so called Russian historical and cultural standard (a model of obligatory diagnosis, assessments and historical interpretations) and as such it should be regarded in tactical as well as in strategic dimensions.
„Wojny pamięci” wyznaczają rosyjską specyfikę problematyki określanej na Zachodzie jako „polityka historyczna” bądź „polityka pamięci”. Argumenty historyczne, wpisane w FR w kontekst wojen informacyjnych i kulturowych oraz utożsamiane z psychologiczną wojną interpretacyjną dziejów, służą do realizacji celów politycznych na arenie wewnętrznej i zewnętrznej: wizje sprzeczne z oficjalną są dyskredytowane jako antyrosyjskie i falsyfikujące historię Rosji. Tekst składa się z trzech części. W pierwszej omówiono ewolucję problemu w rosyjskim dyskursie publicznym po rozpadzie ZSRR, ze szczególnym uwzględnieniem historiografii resortowej nadającej kierunek walce informacyjnej z historią w tle. W części drugiej pokazano miejsce rosyjskich służb specjalnych w praktyce prowadzenia tej walki, a także jej przejawy na płaszczyźnie kulturowej, strukturalnej i wydarzeniowej. W części trzeciej przedstawiono wizję historycznych relacji polsko- -rosyjskich w optyce historiografii FR. Jest to wizja konfrontacyjna, zorientowana na budowanie napięć. Legła ona także u podstaw tzw. rosyjskiego standardu historyczno- kulturowego (wzorca obligatoryjnych diagnoz, ocen i interpretacji historycznych), w związku z czym należy ją rozpatrywać zarówno w wymiarze taktycznym, jak i strategicznym.
Źródło:
Przegląd Bezpieczeństwa Wewnętrznego; 2019, 11, 20; 233-257
2080-1335
2720-0841
Pojawia się w:
Przegląd Bezpieczeństwa Wewnętrznego
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
[Szkolenie ukraińskich funkcjonariuszy Straży Granicznej] : kalendarium Centrum Szkolenia Straży Granicznej : 12-16.03.2007 r.
Autorzy:
Skóra, Andrzej.
Powiązania:
Problemy Ochrony Granic. Biuletyn 2007, nr 36, s. 190-191
Data publikacji:
2007
Tematy:
Mączka, Iwona
Straż Graniczna. Komenda Główna SG (Warszawa). Zarząd ds. Cudzoziemców KG SG pracownicy 2007 r.
Centrum Szkolenia Straży Granicznej (Kętrzyn, woj. warmińsko-mazurskie) 2007 r. kalendarium
Migracje polityka szkolenie
Opis:
Zajęcia prowadziła por. SG Ilona Mączka, zca naczelnika Zarządu ds. Cudzoziemców KGSG.
Fot.
Dostawca treści:
Bibliografia CBW
Artykuł
Tytuł:
Evaluation of Rheological Behaviour upon Recycling of an Ethylene Vinyl Acetate Copolymer by Means of Twin-Screw Extrusion Process
Autorzy:
Fatih Ergin, M.
Aydin, I.
Powiązania:
https://bibliotekanauki.pl/articles/1032038.pdf
Data publikacji:
2017-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
47.85.md
83.80.Sg
47.57.Ng
83.80.-k
81.20.Hy
Opis:
Recycling of many polymers has gained a spectacular importance mainly because of its environmental and economical benefits. Ethylene vinyl acetate is one of the thermoplastics used directly as a final product and indirectly as an additive within many other polymeric materials. There has been limited research work on recycling of polymers even though recycling in industry has shown a spectacular growth in the last decade. It is the aim of this study to investigate and to evaluate the rheological behaviour of an ethylene-vinyl acetate copolymer resin upon recycling. For this purpose, original ethylene vinyl acetate granules were processed five cycles by using a twin-screw extruder and their rheological analysis was performed by means of an AR-G2 rheometer (TA Instruments), with a parallel-plate geometry, under a steady state condition. It was found that the rheological measurements of copolymer ethylene vinyl acetate exhibited a shear thinning constitutive behavior, obeying Carreau-Yasuda rheological constitutive model. The changes in flow and oscillatory shear measurements under different processing conditions were also determined in detail and results are reported in the paper.
Źródło:
Acta Physica Polonica A; 2017, 131, 3; 542-544
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Structural and Magnetic Studies of the Fe-Co-Zr-Mo-W-B Amorphous Alloy
Autorzy:
Kotynia, K.
Pawlik, P.
Hasiak, M.
Pruba, M.
Pawlik, K.
Powiązania:
https://bibliotekanauki.pl/articles/1030235.pdf
Data publikacji:
2017-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.43.Dq
75.50.Kj
75.30.Sg
75.30.Kz
75.40.-s
Opis:
The paper presents a characterization of the phase structure by X-ray diffraction and isothermal magnetic entropy changes for the amorphous Fe₅₈Co₁₀Zr₁₀Mo₅W₂B₁₅ alloy sample in the as-quenched state. An ingot sample was obtained by arc-melting. The ribbon sample was obtained by the melt-spinning technique. The magnetic measurements at various temperatures allowed for the study of the Curie temperature T_{C} and magnetic entropy changes |ΔS_{M}|. In order to determine the Curie temperature T_{C} of amorphous phase, three independent methods were used. Determination of the Curie temperature T_{C} for the amorphous alloys is not a trivial problem, as magnetization does not decreases rapidly around T_{C}. Therefore it is essential issue to establish T_{C} using few complementary methods. X-ray diffraction analysis revealed a fully amorphous structure of the ribbon samples.
Źródło:
Acta Physica Polonica A; 2017, 131, 5; 1204-1206
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Współpraca Małopolskiego Inspektoratu Okręgowego Straży Granicznej z organami administracji państwowej i Policją Państwową : z historii granic
Autorzy:
Kozłowski, Piotr.
Powiązania:
Biuletyn Centralnego Ośrodka Szkolenia Straży Granicznej 2006, nr 4, s. 169-182
Data publikacji:
2006
Tematy:
Straż Graniczna Małopolski Inspektorat Okręgowy SG 1928-1939 r.
Straż graniczna Polska 1928-1939 r.
Opis:
Tab.
Dostawca treści:
Bibliografia CBW
Artykuł
Tytuł:
The Superconducting and Magnetic States in $RuSr_2GdCu_2O_8$, Based on the Magnetic, Transport and Magneto-Caloric Characteristics
Autorzy:
Klamut, P.
Plackowski, T.
Powiązania:
https://bibliotekanauki.pl/articles/1536600.pdf
Data publikacji:
2010-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.72.-h
75.30.-m
74.62.Bf
74.25.F-
75.30.Sg
Opis:
The article discusses selected properties of the non- and superconducting polycrystalline samples of $RuSr_2GdCu_2O_8$ and comments on the consequences of introducing insignificant sub-stoichiometry of Ru into the nominal formula. The magneto-resistive and the magnetic characteristics are interpreted in favour of the formation of intrinsically inhomogeneous superconducting phase, which seems stabilized along with the structural modifications enhanced with the modification of starting stoichiometry. The specific heat data reveals the small shift of the temperature of magnetic ordering $T_{m}$, which may suggest dilution of the magnetic sublattice of the Ru moments. The measurements of the magnetic field dependences of the isothermal magnetocaloric coefficient $M_{T}$ reveal no gain in the system magnetic entropy in a broad range of accessed fields and temperature. Whereas the multi-component character of the compound's magnetsm precludes from concluding on the magnetic ground state, the maximum in $M_T (H)$, which occurs at comparably weak magnetic field for temperatures in a vicinity of $T_{m}$ may reflect dominance of the ferromagnetic type interactions with a constrained correlation range. The literature explored models for the Ru magnetic ordering and also possible phase separation are brought into the discussion.
Źródło:
Acta Physica Polonica A; 2010, 118, 2; 254-260
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Microstructure and Magnetic Properties of La-Ca-Sr-Mn-O Perovskite Ceramics
Autorzy:
Zmorayova, K.
Antal, V.
Radusovska, M.
Piovarci, S.
Kováč, J.
Kavecansky, V.
Diko, P.
Powiązania:
https://bibliotekanauki.pl/articles/1367705.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Sg
75.47.Lx
77.80.Bh
81.20.Ev
81.30.Fb
Opis:
$La_{0.67}Ca_{0.33-x}Sr_{x}MnO_{3}$ (x=0.33; 0.03; 0) (LCSM) perovskite magnetocaloric ceramics were prepared by solid state synthesis in air and sintering at 1520°. The phase composition was checked by x-ray powder diffraction. Microstructure analyses were done by scanning electron microscopy. The influence of high pressure oxygenation on magnetisation behaviour is shown.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 168-169
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetization Process and Adiabatic Demagnetization of the Antiferromagnetic Spin-1/2 Heisenberg Cubic Cluster
Autorzy:
Strečka, J.
Čisárová, J.
Powiązania:
https://bibliotekanauki.pl/articles/1366469.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.10.Jm
75.30.Sg
75.40.Cx
75.50.Ee
75.60.Ej
Opis:
A full energy spectrum of the spin-1/2 Heisenberg cubic cluster is used to investigate a low-temperature magnetization process and adiabatic demagnetization of this zero-dimensional 2×2×2 quantum spin system. It is shown that the antiferromagnetic spin-1/2 Heisenberg cube exhibits at low enough temperatures a stepwise magnetization curve with four intermediate plateaux at zero, one quarter, one half, and three quarters of the saturation magnetization. We have also found the enhanced magnetocaloric effect close to level-crossing fields that determine transitions between the intermediate plateaux.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 26-27
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
SG 550 [karabinek] : ilustrowana encyklopedia współczesnej broni palnej
Autorzy:
Woźniak, Ryszard.
Zahor, Mirosław.
Powiązania:
Wojskowy Przegląd Techniczny i Logistyczny 2001, nr 5, s. 19-22
Współwytwórcy:
Woźniak, Ryszard. Redakcja
Data publikacji:
2001
Tematy:
SG 550 (karabinek) budowa i konstrukcje Szwajcaria
Karabinki budowa i konstrukcje Szwajcaria
Broń palna encyklopedia
Opis:
Fot.
Dostawca treści:
Bibliografia CBW
Artykuł
Wyświetlanie 1-100 z 191

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