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Wyszukujesz frazę "75.50.Gg" wg kryterium: Temat


Tytuł:
$\text{}^{57}$Fe Hyperfine Field Anisotropy in Ferrites and its Relation to the Non-Uniformity of the Ionic Surrounding
Autorzy:
Štepánková, H.
Englich, J.
Kohout, J.
Powiązania:
https://bibliotekanauki.pl/articles/2013366.pdf
Data publikacji:
2000-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
76.60.-k
75.50.Gg
Opis:
The hyperfine field anisotropy tensors, obtained from analysis of $\text{}^{57}$Fe NMR spectra for iron sites in various magnetic oxides (barium hexaferrite, lithium spinel, magnetite and yttrium-iron garnet) were used to investigate the relation between the hf anisotropy and surrounding ionic arrangement. While a reasonable correlation has been found when the distribution of the nearest cations was considered, no correlation was obtained between the hyperfine field anisotropy and the positions of the nearest oxygen anions.z
Źródło:
Acta Physica Polonica A; 2000, 97, 5; 757-760
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:
Analysis of Magnetic Ground State in Thulium Iron Garnets
Autorzy:
Koper, A.
Lehmann-Szweykowska, A.
Wigen, P. E.
Bornfreund, R. E.
Powiązania:
https://bibliotekanauki.pl/articles/1964707.pdf
Data publikacji:
1997-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Lk
75.50.Gg
75.50.-y
75.40.Μg
75.10.Hk
Opis:
Magnetic phase diagrams of thulium iron garnets at Τ = 0 K are obtained by means of the so-called Monte Carlo relaxation method. The diagrams are given in terms of the respective strength of the superexchange couplings. There are five different phases and one spin-flop line on the diagram obtained. Two of these phases are of a semi-spin glass type.
Źródło:
Acta Physica Polonica A; 1997, 92, 2; 391-394
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Antisite Defects in Epitaxial Films of Lutetium Doped Yttrium Iron Garnets Studied by Nuclear Magnetic Resonance
Autorzy:
Chlan, V.
Štěpánková, H.
Englich, J.
Řezníček, R.
Kouřil, K.
Kučera, M.
Nitsch, K.
Powiązania:
https://bibliotekanauki.pl/articles/1534129.pdf
Data publikacji:
2010-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Gg
76.60.-k
76.60.Lz
68.35.Dv
68.55.Ln
Opis:
Series of lutetium doped yttrium iron garnet films is studied by means of $\text{}^{57}Fe$ nuclear magnetic resonance. Satellite spectral lines are resolved and identified in the spectra and concentrations of lutetium in dodecahedral sites as well as yttrium/lutetium antisite defects in octahedral sites are estimated. Compared to yttrium, lutetium cations are found to have stronger disposition towards creating the antisite defects.
Źródło:
Acta Physica Polonica A; 2010, 118, 5; 846-847
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Biogenic Magnetite Nanoparticle Ensemble Use in MRI Diagnostics
Autorzy:
Strbak, O.
Krafcik, A.
Teplan, M.
Gogola, D.
Kopcansky, P.
Frollo, I.
Powiązania:
https://bibliotekanauki.pl/articles/1202318.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Gg
75.50.Tt
87.61.-c
Opis:
We present a simple analytical tool, which allows the calculation of the MRI diagnostics feasibility of the biogenic magnetite nanoparticles. Elevated levels of these particles are usually linked to the pathological processes, especially to neurodegenerative disorders. We showed theoretically that the biogenic magnetite itself is not sufficient for the non-invasive diagnostics and must be extended with the total iron incorporated in other biological structures.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 388-389
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cation Distribution in Fe$\text{}_{3(1-\delta)}$O$\text{}_{4}$ and Low Level Doped Fe$\text{}_{3-x}$M$\text{}_{x}$O$\text{}_{4}$, M=Ti, Zn, Al
Autorzy:
Kąkol, Z.
Kozłowski, A.
Sabol, J.
Metcalf, P.
Honig, J. M.
Powiązania:
https://bibliotekanauki.pl/articles/1861287.pdf
Data publikacji:
1994-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.80.Ga
75.30.Cr
75.50.Gg
Opis:
Systematic magnetic saturation moment and electrical resistivity measurements of the Fe$\text{}_{3(1-\delta)}$O$\text{}_{4}$ and Fe$\text{}_{3-x}$M$\text{}_{x}$O$\text{}_{4}$ (M = Ti, Zn, Al) are presented. Cation distributions for low level doping are proposed and compositional dependencies of the Verwey transition temperature are determined. The latter show striking similarities in their dependence on cation vacancies and dopant concentration for any extraneous cations. These data are the basis for the analysis of the correlation between the presented cations distributions and the Verwey transition.
Źródło:
Acta Physica Polonica A; 1994, 85, 1; 223-227
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Complex Permeability of LiZn/MnZn/PVC Composite Materials
Autorzy:
Dosoudil, R.
Ušáková, M.
Grusková, A.
Sláma, J.
Powiązania:
https://bibliotekanauki.pl/articles/1535468.pdf
Data publikacji:
2010-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.80.Tm
75.50.Gg
76.50.+g
Opis:
The effect of particle content, size, and the fraction ratio of the double LiZn/MnZn ferrite filler in hybrid LiZn/MnZn/PVC composites on the frequency dispersion of complex permeability has been studied in the 1 MHz-3 GHz frequency range. The obtained relaxation type of permeability dispersion is due to the domain wall resonance, the natural ferromagnetic resonance, and the relaxation of magnetization rotation. The permeability and resonance/relaxation frequency of composites seem to be strongly affected by the change of particle content and fraction ratio of the double ferrite filler rather than by particle size.
Źródło:
Acta Physica Polonica A; 2010, 118, 5; 1049-1050
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Conductivity and Magnetism of Magnetic Oxides
Autorzy:
Gehring, G. A.
Powiązania:
https://bibliotekanauki.pl/articles/2012877.pdf
Data publikacji:
2000-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
75.50.Gg
Opis:
In a stoichiometric oxide the energy for the magnetic ordering is due to superexchange. This depends on the virtual transfer of a d electron from the transition ion to the neighbouring oxygen. When the oxide is p-doped there are compensating holes on the oxygen or the transition ion becomes mixed valent. The oxide may then conduct. The same transfer integral enters both the expression for the antiferromagnetic superexchange and the band width of the mobile carriers. Thus materials with a large antiferromagnetic exchange energy will be expected to have a relatively wide conduction band in the doped state and hence to have a high conductivity. In this paper the difference is explored between the materials in which there is true antiferromagnetism and those which are ferrimagnetic. In the antiferromagnets the carriers must destroy the magnetic order as they move. This behaviour is well known from the cuprates. In ferrimagnets the carriers may be able to move entirely on one sublattice. This occurs in Fe$\text{}_{3}$O$\text{}_{4}$ and probably in the doped garnets. In the case where motion is on one sublattice then doping does not destroy the magnetism and there is a relatively small magnetoresistance. An interesting feature is that unlike the cuprates the ferrimagnets do not become good metals at any doping but exhibit hopping conductivity. We explain the apparent paradox that the best conductivity is actually observed in materials where the conduction is only allowed when the antiferromagnetism has been quenched and that the conductivity in ferrimagnets is low.
Źródło:
Acta Physica Polonica A; 2000, 97, 1; 175-184
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Crystal Structure and Magnetic Properties of Pyrrhotite-Type Compounds $Fe_{7-y}V_{y}S₈$
Autorzy:
Selezneva, N.
Ibrahim, P.
Toporova, N.
Sherokalova, E.
Baranov, N.
Powiązania:
https://bibliotekanauki.pl/articles/1397027.pdf
Data publikacji:
2018-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.66.Fn
75.30.Kz
75.50.Gg
Opis:
The pyrrhotite-type compounds $Fe_{7-y}V_{y}S₈$ have been synthesized and studied by means of the X-ray diffraction and magnetization measurements in order to reveal how the substitution of V for Fe affects the crystal structure, phase transition and magnetic properties. The growth of the V content in $Fe_{7-y}V_{y}S₈$ results in changes of the crystal structure and leads to a sharp decrease in the resultant magnetization, non-monotonous change of the coercive field and reduction of the magnetic ordering temperature. Unlike ferrimagnetic ordering in pyrrhotite Fe₇S₈ the compound V₇S₈ is observed to exhibit a Pauli-paramagnetic behaviour.
Źródło:
Acta Physica Polonica A; 2018, 133, 3; 450-452
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Distribution of Zn in Magnetoelectric Y-Type Hexaferrite
Autorzy:
Kouřil, K.
Chlan, V.
Štěpánková, H.
Telfah, A.
Novák, P.
Knížek, K.
Hiraoka, Y.
Kimura, T.
Powiązania:
https://bibliotekanauki.pl/articles/1506927.pdf
Data publikacji:
2010-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.05.Qr
75.85.+t
75.50.Gg
31.15.E-
Opis:
We employ $\text{}^{67}Zn$ NMR to study distribution of $Zn^{2+}$ in cationic sites of magnetoelectric Y-type hexaferrite single crystal, $Ba_{0.5} Sr_{1.5} Zn_2 Fe_{12} O_{22}$. The experimental data are interpreted by comparison with NMR spectra simulated from ab initio calculated hyperfine parameters.
Źródło:
Acta Physica Polonica A; 2010, 118, 5; 732-733
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Fe substitution on structural and magnetic properties of NiCr₂O₄
Autorzy:
Mohanty, P.
Prinsloo, A.
Sheppard, C.
Roos, W.
Powiązania:
https://bibliotekanauki.pl/articles/1048307.pdf
Data publikacji:
2018-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Gg
75.60.-d
Opis:
At room temperature, the normal oxide spinel NiCr₂O₄ is tetragonally distorted and crystallizes in the I4₁/amd space group due to cooperative Jahn-Teller ordering driven by the orbital degeneracy of tetrahedral Ni²⁺. The ferrimagnetic Curie temperature (T_{C}) for NiCr₂O₄ is 74 K. The magnetic moments of NiCr₂O₄ are composed of a ferrimagnetic (longitudinal) and an antiferromagnetic (transverse) component. Exchange interaction between the magnetic cations influences the overall magnetic properties of the compound. Present work focuses on the modification of structural and magnetic properties upon substituting Fe at Cr site in NiCr₂O₄ with the motivation of changing the magnetic exchange interaction. In order to do so, single phase Ni(Cr_{0.5}Fe_{0.5})₂O₄ samples were prepared by co-precipitation techniques, while controlling the pH of precipitation. Upon Fe substitution, crystal structure was not affected much contrary to the earlier reports. In order to determine the oxidation state of each elements X-ray photoelectron spectroscopy (XPS) was performed. T_{C} was found to increase dramatically above 300 K, confirmed both from temperature and field dependent dc-magnetization studies.
Źródło:
Acta Physica Polonica A; 2018, 133, 3; 574-577
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Filler Mixture Ratio on Permeability of Multicomponent Soft Magnetic Composites
Autorzy:
Dosoudil, R.
Ušáková, M.
Grusková, A.
Sláma, J.
Powiązania:
https://bibliotekanauki.pl/articles/1202349.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Gg
75.50.Bb
76.50.+g
75.78.-n
72.80.Tm
Opis:
Composites with hybrid LiZnTi ferrite/FeSiAl alloy filler and PVC polymer matrix were synthesized by thermal pressing process. The influence of the mixture ratio of hybrid filler on the frequency dispersion of complex permeability of the composites has been studied. The dispersion of permeability varied from resonance type to relaxation one with the configuration change from LiZnTi/PVC composite to FeSiAl/PVC one and was mainly due to the magnetic resonance phenomena such as domain wall and spin precession resonance and due to the eddy current effect.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 404-405
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Manganese on Magnetic and Electrical Properties of the RMn$\text{}_{x}$T$\text{}_{12-x}$ Alloys
Autorzy:
Suski, W.
Wochowski, K.
Mydlarz, T.
Belan, B.
Powiązania:
https://bibliotekanauki.pl/articles/2014385.pdf
Data publikacji:
2000-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Gg
75.20.-g
75.20.En
75.50.Ee
Opis:
The magnetic and electrical properties of the tetragonal, ThMn$\text{}_{12}$-type RMn$\text{}_{x}$T$\text{}_{12-x}$ alloys (R = Y, Ce, Pr, Nd, Sm and T = Fe, Co, Ni) were studied in broad temperature and magnetic field ranges to elucidate an influence of manganese on the magnetic ordering in these materials. Magnetic properties were examined at T=1.7-300K in magnetic field up to 14T, whereas the electrical properties were examined at T=4.2-300K, on the polycrystalline samples. Majority of the samples exhibit ferro- or ferrimagnetic properties. Some samples containing larger concentration of Mn are paramagnetic in the whole temperature range. The electrical resistivity of these alloys shows metallic character.
Źródło:
Acta Physica Polonica A; 2000, 98, 5; 505-511
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Nd³⁺ doping on magnetic and dielectric properties of SrFe₁₂O₁₉ hexaferrite synthesized by coprecipitation method
Autorzy:
Hilczer, A.
Pasińska, K.
Markiewicz, E.
Pietraszko, A.
Andrzejewski, B.
Powiązania:
https://bibliotekanauki.pl/articles/1047614.pdf
Data publikacji:
2018-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Gg
75.60.Ej
75.75.+a
81.20.Fw
Opis:
Magnetic and dielectric properties of hexagonal ferrites important for applications in microwave absorbers are strongly determined by the processing conditions. We studied dielectric and magnetic response of Sr_{1-x}Nd_{x}Fe₁₂O₁₉ (x=0, 0.03, 0.05, 0.07, 0.09) solid solutions obtained by coprecipitation method. The structure of the samples was controlled by X-ray diffraction and scanning electron microscope images revealed that the powder is a mixture of small nanograins and crystallites of 500 nm-1 μm in size. Nd³⁺ doping was found to result in an increase in the coercive field which we would like to relate to the domain wall pinning. The doping-induced changes are monotonous with x up to 0.07. The observed dispersion of permittivity was found to be correlated with the frequency behaviour of electric conductivity of the samples.
Źródło:
Acta Physica Polonica A; 2018, 133, 3; 669-672
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Pressure on Magnetic Properties of $TM_3[Cr(CN)_6]_2 \cdot nH_2O$ Nanoparticles
Autorzy:
Zentko, A.
Zentková, M.
Kavečanský, V.
Mihalik, M.
Mitróová, Z.
Arnold, Z.
Kamarád, J.
Cieslar, M.
Zeleňák, V.
Powiązania:
https://bibliotekanauki.pl/articles/1813843.pdf
Data publikacji:
2008-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Cr
75.50.Ee
75.50.Gg
75.50.Xx
Opis:
Effect of pressure on magnetic properties of magnetic nanoparticles, based on Prussian blue analogues, were studied in pressures up to 1.2 GPa. The $Mn_3[Cr(CN)_6]_2 \cdot nH_2O$ and $Ni_3[Cr(CN)_6]_2 \cdot nH_2O$ nanoparticles were prepared by reverse micelle technique. Transmission electron microscopy images show nanoparticles with average diameter of about 3.5 nm embedded in an organic matrix. The characteristic X-ray peaks of nanoparticles are more diffused and broader. Systems of nanoparticles behave as systems of interacting magnetic particles. The Curie temperature $T_C$ is reduced from $T_C$ = 56 K for Ni-Prussian blue analogues to $T_C$ = 21 K for Ni-nanoparticles system and from $T_C$ = 65 K for Mn-Prussian blue analogues to $T_C$ = 38 K for Mn-nanoparticles system. One can explain this reduction of the Curie temperature and of the saturated magnetization $μ_s$ by dispersion of nanoparticles in an organic matrix i.e. by a dilution effect. Applied pressure leads to a remarkable increase in $T_C$ for system of Mn-nanoparticles (Δ$T_C$/Δp = +13 K/GPa) and to only slight decrease in $T_C$ for system of Ni-nanoparticles (Δ$T_C$/Δp = -3 K/GPa). The pressure effect follows behavior of the mother Prussian blue analogues under pressure. The increase in saturated magnetization, attributed to compression of the organic matrix, is very small.
Źródło:
Acta Physica Polonica A; 2008, 113, 1; 489-493
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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