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    Wyświetlanie 1-15 z 15
    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:
    Neutron Diffraction Studies of Nanoparticle $DyMnO_3$ Compound
    Autorzy:
    Szytuła, A.
    Penc, B.
    Dyakonov, V.
    Baran, S.
    Hoser, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/1206328.pdf
    Data publikacji:
    2014-01
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    61.05.F-
    75.25.-j
    75.50.Ee
    Opis:
    The neutron powder diffraction (NPD) measurements of the nano-size $DyMnO_3$ manganite have been performed. The obtained results indicate that this compound crystallizes in the orthorhombic crystal structure described by the space group Pnma. The Mn and Dy moments order antiferromagnetically at different temperatures and form modulated magnetic structure described by the propagation vector k=($k_x$, 0, 0) with the different values of $k_x$ component for the Mn and Dy sublattices. The values of $k_x$ component for Mn sublattice increase with decreasing of the temperature and are smaller that in bulk compound. The wide Bragg peaks related to the Dy sublattice suggest that the magnetic order in this sublattice has the cluster-like character.
    Źródło:
    Acta Physica Polonica A; 2014, 125, 1; 65-66
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Ferromagnetic Resonance Studies of La$\text{}_{0.67}$Ca$\text{}_{0.33}$MnO$\text{}_{3}$ Film under Stress
    Autorzy:
    Kundys, B.
    Dyakonov, V. P.
    Baran, M.
    Gierłowski, P.
    Szymczak, R.
    Powiązania:
    https://bibliotekanauki.pl/articles/2037113.pdf
    Data publikacji:
    2004
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    73.50.Jt
    75.80.+q
    68.60.Bs
    71.70.Ej
    Opis:
    Ferromagnetic resonance spectra of the La$\text{}_{0.67}$Ca$\text{}_{0.33}$MnO$\text{}_{3}$ ferromagnetic film deposited onto the x-cut LiNbO$\text{}_{3}$ substrate were investigated in a wide temperature range. The strain was mechanically introduced into the film using a special holder configuration. This leads to a shift of resonance field with respect to that of the as-grown sample. Analysis of the magnetic resonance shift, induced by a mechanical stress, allowed us to determine the magnetostriction constant λ$\text{}_{100}$. The magnetostriction determined in this way versus saturation magnetization could be well described by the Callen and Callen theory suggesting the domination of the single ion crystal field interaction in the sample being in the ferromagnetic state.
    Źródło:
    Acta Physica Polonica A; 2004, 105, 1-2; 133-139
    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:
    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:
    Low-Temperature Structural Phase Transition in Monoclinic RbDy(WO$\text{}_{4}$)$\text{}_{2}$ Crystal
    Autorzy:
    Borowiec, M. T.
    Dyakonov, V.
    Kamenev, V.
    Nabiałek, A.
    Prokhorov, A.
    Szymczak, H.
    Załęski, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/1968975.pdf
    Data publikacji:
    1998-07
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    76.30.-v
    75.20.-g
    Opis:
    The ESR spectrum of Dy$\text{}^{3+}$ ion in the low-symmetry RbDy(WO$\text{}_{4}$)$\text{}_{2}$ crystal has been studied in the temperature region of T=4.2 ÷ 30K. The ESR linewidth was found to increase from 130 mT up to the maximum value of 190 mT at T=9K and then to decrease down to 150 mT at 4.2K. The components of the g-tensor change considerably without change of their spatial orientation in the temperature range from 12K to 7 K: g$\text{}_{z}$=2.5, g$\text{}_{x}$≈0, g$\text{}_{y}$=1.41 at T>12 K; g$\text{}_{z}$=1.53, g$\text{}_{x}$≈0, g$\text{}_{y}$=1.2 at T<7K. The observed λ-shaped behaviour of absorption linewidth and the decrease in the g-factor are assumed to be due to the low-temperature structural phase transition (T$\text{}_{SPT}$≈9 K). The width of the transition area is of about 5K. It is suggested that the symmetry of high- and low-temperature phases is identical.
    Źródło:
    Acta Physica Polonica A; 1998, 94, 1; 71-77
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Pinning Force in Superconducting Wires Nb-Ti
    Autorzy:
    Gajda, D.
    Zaleski, A.
    Dyakonov, V.
    Matrosov, N.
    Szymczak, H.
    Beloshenko, V.
    Spuskanyuk, V.
    Chishko, V.
    Powiązania:
    https://bibliotekanauki.pl/articles/1537076.pdf
    Data publikacji:
    2010-08
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    84.71.Mn
    Opis:
    In the paper we present the results of the measurements of critical current $I_{c}$ in NbTi wires. Experiments were made for the wires of 0.3 mm in diameter and the length of 25 mm. The wires were produced by means of two methods: conventional (hydroextrusion and drawing) and preliminary equal channel multiple angle pressing. The samples were heat treated at different temperatures. We describe the influence of different pinning centers on critical current density $J_{c}$.
    Źródło:
    Acta Physica Polonica A; 2010, 118, 2; 364-365
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Surface Magnetic Anisotropy of Epitaxial La$\text{}_{0.7}$Mn$\text{}_{1.3}$O$\text{}_{2.84}$ Thin Films
    Autorzy:
    Aleshkevych, P.
    Baran, M.
    Dyakonov, V.
    Szymczak, R.
    Szymczak, H.
    Baberschke, K.
    Lindner, J.
    Lenz, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/2046886.pdf
    Data publikacji:
    2006-07
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    76.50.+g
    75.70.-i
    Opis:
    A spin-wave resonance technique was used to collect information on elementary magnon excitations in high quality epitaxial La$\text{}_{0.7}$Mn$\text{}_{1.3}$O$\text{}_{2.84}$ films prepared by dc-magnetron sputtering. It was found that besides bulk spin-wave modes, the spin-wave resonance spectrum includes also the surface spin waves. The value of spin-wave stiffness constant D=156 meV·Å$\text{}^{2}$ was found. The values of the surface magnetic anisotropy on both surfaces and their angular dependence were determined. The experimentally found spin-wave resonance spectra were explained based on the surface-inhomogeneity model. The effect of surface anisotropy on the spin-wave excitation conditions in epitaxial La$\text{}_{0.7}$Mn$\text{}_{1.3}$O$\text{}_{2.84}$ films was investigated. Spin-wave resonance data give an indirect evidence of periodic charge-ordered stripes formation.
    Źródło:
    Acta Physica Polonica A; 2006, 110, 1; 57-70
    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:
    Magnetic and Ferroelectric Ordering in the $TbMnO_3$ Film
    Autorzy:
    Sazanovich, A.
    Nikolaenko, Yu.
    Paszkowicz, W.
    Mikhaylov, V.
    Dyakonov, K.
    Medvedev, Yu.
    Nizhankovskii, V.
    Dyakonov, V.
    Szymczak, H.
    Powiązania:
    https://bibliotekanauki.pl/articles/1207010.pdf
    Data publikacji:
    2014-01
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    75.47.Lx
    75.85.+t
    75.70.Ak
    77.55.Nv
    Opis:
    Measurements of magnetization and electric polarization performed for the $TbMnO_3$ film grown onto the single crystal [100] $SrTiO_3$ substrate using magnetron sputtering technique exhibit series of anomalies related to the magnetic and electric ordering of the $Tb^{3+}$ and $Mn^{3+}$ sublattices. The detailed temperature dependences of the electric polarization and dielectric constant of the $TbMnO_3$ film have shown that the ferroelectric phase appears below 30 K in magnetic field H > 1 T applied in-plane and out-of-plane of the film.
    Źródło:
    Acta Physica Polonica A; 2014, 125, 1; 128-130
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Manifestation of Spin-Glass-Like Behavior in the Organometallic Magnet
    Autorzy:
    Dyakonov, V. P.
    Arciszewska, M.
    Dobrowolski, W.
    Szewczyk, A.
    Szymczak, H.
    Aksymentieva, E.
    Varyukhin, V.
    Zubov, E.
    Gutowska, M. U.
    Powiązania:
    https://bibliotekanauki.pl/articles/2013705.pdf
    Data publikacji:
    2000-05
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    75.30.Kz
    75.40.Cx
    Opis:
    Ac susceptibility (χ$\text{}_{ac}$) and dc magnetization (M$\text{}_{dc}$) of the organometallic magnet Na[FeO$\text{}_{6}$(C$\text{}_{10}$H$\text{}_{8}$N)$\text{}_{3}$] have been studied in temperature range of 4.2-200 K, in an external magnetic field up to 16 kOe. Some peculiarities of the χ$\text{}_{ac}$ and M $\text{}_{dc}$ behavior, which are characteristic of spin-glasses, e.g. cusps in the susceptibility and zero-field-cooled magnetization, an irreversibility between the field-cooled and zero-field-cooled magnetization and dependences of the T$\text{}_{cusp}$ temperature on the frequency and the intensity of the magnetic field, were observed at low temperatures.
    Źródło:
    Acta Physica Polonica A; 2000, 97, 5; 863-866
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Magnetic Properties of the Nanocrystalline $DyMnO_{3}$ Compound
    Autorzy:
    Dyakonov, V.
    Szytuła, A.
    Baran, S.
    Kravchenko, Z.
    Zubov, E.
    Iessenchuk, O.
    Bazela, W.
    Dul, M.
    Zarzycki, A.
    Szymczak, H.
    Powiązania:
    https://bibliotekanauki.pl/articles/1538453.pdf
    Data publikacji:
    2010-04
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    61.05.cp
    75.47.Lx
    75.50.Ee
    75.75.-c
    Opis:
    We report on the X-ray powder diffraction and magnetic measurements of the polycrystalline and the two nanocrystalline samples of $DyMnO_{3}$ compound synthesized at temperatures of 800 and 850°C. All samples at room temperature crystallize in the orthorhombic crystal structure (space group Pnma). The crystal structure parameters determined change only slightly with preparation methods but the average grains size of the nanoparticles determined from X-ray data increases significantly with increasing annealing temperature. Temperature dependence of the magnetic susceptibility indicates the antiferromagnetic order in Dy sublattice at low temperatures.
    Źródło:
    Acta Physica Polonica A; 2010, 117, 4; 607-610
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Magnetic and Neutron Diffraction Studies of the Polycrystalline and Nanoparticle $TbMnO_3$
    Autorzy:
    Bażela, W.
    Dul, M.
    Dyakonov, V.
    Gondek, Ł.
    Hoser, A.
    Hoffmann, J.
    Penc, B.
    Szytuła, A.
    Kravchenko, Z.
    Nosalev, I.
    Zarzycki, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/1419577.pdf
    Data publikacji:
    2012-08
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    75.40.Cx
    75.47.Lx
    75.25.-j
    75.50.Ee
    Opis:
    This paper reports on investigations of magnetic properties, crystal and magnetic structures on $TbMnO_3$ prepared in various ways, namely, as conventional polycrystalline sample and two nano particle specimens (synthesized with a sol-gel method at temperatures of 800 and 850°C). The X-ray and neutron diffraction data confirm the orthorhombic crystal structure (space group Pbnm, No. 62) without noticeable differences of the lattice parameters for poly- and nanocompounds. For the polycrystalline sample, a subsequent ordering of the Mn and Tb sublattices with decreasing temperature was observed. Namely, the Mn sublattice exhibits a modulated magnetic structure with the propagation vector k = (0, $k_{x},$ 0) in between 41-5 K. Below T = 21 K, a change from a collinear ($A_{y}$ mode) into non-collinear ($A_{y}G_{z}$ mode) structure was evidenced. Further decreasing of temperature below 10 K results in magnetic ordering of the Tb sublattice (modulated $G_{x}A_{y}F_{z}$ mode). For nanoparticle compounds, magnetic ordering in the Mn and Tb sublattices is described by propagation vector k = (0, $k_{y},$ 0), with $k_{y}$ components higher than observed for polycrystalline sample. The magnetic ordering in the Mn sublattice is described by a collinear $A_{y}$ mode down to 1.6 K where the Tb moment becomes ordered ($G_{x}A_{y}$ mode). The observed broadening of the Bragg peaks connected to the Tb sublattice suggests the cluster-like character of its magnetic structure.
    Źródło:
    Acta Physica Polonica A; 2012, 122, 2; 384-390
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Influence of the Grain Size on the Magnetic Properties of $TbMnO_{3}$
    Autorzy:
    Bażela, W.
    Dul, M.
    Dyakonov, V.
    Gondek, Ł.
    Hoser, A.
    Hoffmann, J.
    Penc, B.
    Szytuła, A.
    Kravchenko, Z.
    Nosalev, I.
    Zarzycki, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/1431251.pdf
    Data publikacji:
    2012-04
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    61.05.Cp
    61.05.F-
    61.05.J-
    75.30.kz
    75.50.Ee
    75.50.-y
    Opis:
    The magnetic properties including magnetic structure of poly and nano samples of $TbMnO_{3}$ are determined. All the samples investigated are antiferromagnets. In these samples the Mn ad Tb moments order antiferromagnetically at different temperatures and form modulated magnetic structure described by the propagation vector k=($k_{x}$,0,0) with different value of $k_{x}$ for the Mn and Tb sublattices. Comparison of the data for poly and nano samples indicates the decrease of the moment and increase of the $k_{x}$ component of propagation vector in the nano specimens. The wide Bragg peak related to the Tb sublattice suggests that the magnetic order has the claster-like character. The magnetic moments value in both sublattices is smaller, whereas the $k_{x}$ values are larger for nano samples.
    Źródło:
    Acta Physica Polonica A; 2012, 121, 4; 785-788
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Crystalline Structure of Potassium Holmium Double Tungstate
    Autorzy:
    Borowiec, M.
    Dyakonov, V.
    Woźniak, K.
    Dobrzycki, Ł.
    Majchrowski, A.
    Michalski, E.
    Zubov, E.
    Khatsko, E.
    Zayarnyuk, T.
    Szewczyk, A.
    Gutowska, M.
    Rykova, A.
    Barański, M.
    Domukhovski, V.
    Shtyrkhunova, V.
    Iwanowski, P.
    Żmija, J.
    Szymczak, H.
    Powiązania:
    https://bibliotekanauki.pl/articles/1505085.pdf
    Data publikacji:
    2011-06
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    61.66.Fn
    Opis:
    The potassium holmium double tungstate was prepared by using top seeded solution growth technique. Structural investigations have been performed at room temperature. The $KHo(WO_4)_2$ single crystal belongs to the monoclinic space group C2/c with the unit-cell parameters: a = 10.624(2) Å, b = 10.352(2) Å, c = 7.5434(15) Å, β = $130.78(3)^{o}$, and Z = 4. The atomic coordinates, isotropic and anisotropic displacement parameters and interionic distances for the studied structure were determined.
    Źródło:
    Acta Physica Polonica A; 2011, 119, 6; 835-837
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-15 z 15

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