共查询到20条相似文献,搜索用时 15 毫秒
1.
J. Restrepo A. L. Morales J. M. González G. A. Pérez Alcázar G. Medina C. A. Barrero J. Tobón G. Pérez O. Arnache J. D. Betancur M. A. Giraldo 《Hyperfine Interactions》2001,134(1):199-206
Samples of nominal composition (Fe0.85Mn0.15)0.3Cu0.7 were prepared by mechanical milling starting from pure element powders. In order to elucidate the effect of the alloying time upon the magnetic properties of the system, milling times ranging from 1 hour up to 72 hours were considered. The phase distribution present on the as-milled materials was identified from the analysis of X-ray diffraction data. The room temperature magnetic properties of the samples were studied by means of 57Fe Mössbauer spectroscopy and vibrating sample magnetometry, whereas their low temperature magnetic behavior was characterized through magnetic susceptibility measurements. The results evidenced a strong dependence of the magnetic properties on the milling time and, concretely, the occurrence of a superparamagnetic behavior in the long-time-milled samples for which an extended solid solution was obtained. This fact is attributable both to the obtained crystallite sizes, which resulted to be of the order of a few nanometers, and to a milling-driven increase of the lattice parameter. 相似文献
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Yu. V. Gerasimova S. N. Sofronova I. A. Gudim A. S. Oreshonkov A. N. Vtyurin A. A. Ivanenko 《Physics of the Solid State》2016,58(1):155-159
Infrared absorption spectra of a Nd0.5Ho0.5Fe3(BO3)4 crystal in the spectral range of 30–1700 cm–1 have been measured at temperatures from 6 to 300 K. The experimental spectra have been analyzed based on the semiempirical calculation of the lattice dynamics and the analysis of correlation diagrams of borate complexes. No changes associated with structural phase transitions have been detected in the temperature range of measurements; the effect of magnetic ordering on the infrared absorption spectra has not been observed. 相似文献
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Eremin E. V. Dubrovskii A. A. Gudim I. A. Titova V. R. Merkulov M. V. 《Physics of the Solid State》2021,63(6):968-971
Physics of the Solid State - Trigonal neodymium scandoborate NdSc3(BO3)4 single crystals have been grown by the batch flux method using bismuth trimolybdate and their magnetic and magnetoelectric... 相似文献
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The magnetic properties of an antiferromagnet with trigonal symmetry, namely, HoFe3(BO3)4, have been investigated theoretically. The calculations have been performed in the molecular field approximation and in the framework of the crystal field model for the rare-earth subsystem. Extensive experimental data on the magnetic properties of HoFe3(BO3)4 have been interpreted and good agreement between theory and experiment has been achieved using the obtained theoretical dependences. The spontaneous spin-reorientation transition and the spin-reorientation transition induced by a magnetic field B ‖ a from the easy-axis to easy-plane state, as well as the spin-flop transition in a magnetic field B ‖ c, have been described. It has been shown that the spontaneous spin-reorientation transition is a magnetic analog of the Jahn-Teller effect. The temperature dependences of the initial magnetic susceptibility at temperatures ranging from 2 to 300 K, the nonlinear curves of magnetization for B ‖ c and B ⊥ c in a magnetic field up to 1.2 T (which indicate the occurrence of first-order phase transitions), and their evolution with variations in the temperature have been described, as well as the temperature and field dependences of the magnetization in a magnetic field up to 9 T. The parameters of the trigonal crystal field for the rare-earth ion Ho3+ and the parameters of the Fe-Fe and Ho-Fe exchange interactions have been determined in the course of interpretation of the experimental data. 相似文献
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A. N. Vasiliev E. A. Popova L. N. Bezmaternykh V. L. Temerov Z. Hiroi 《Journal of Experimental and Theoretical Physics》2006,102(2):262-265
The specific heat was measured in the range 0.4–300 K in YFe3(BO3)4, Y0.5Gd0.5Fe3(BO3)4, and GdFe3(BO3)4 single crystals. Sharp anomalies were found at temperatures of first-order structural, second-order antiferromagnetic, and
first-order spin-reorientational transitions. A Néel temperature of about 37 K was found to be virtually independent of presence
of rare-earth ions, indicating rather weak coupling of Gd and Fe subsystems. The contribution of the magnetic system to specific
heat was separated through the scaling procedure allowing determination of the magnetic entropy of Fe and Gd subsystems. At
the lowest temperatures, the specific heat in GdFe3(BO3)4 exhibits a Schottky-type anomaly, which is due to Gd3+ eightfold degenerate ground-level splitting by the internal magnetic field of the Fe subsystem of about 7 T.
The text was submitted by the authors in English. 相似文献
8.
Kuz’min N. N. Boldyrev K. N. Leonyuk N. I. Stefanovich S. Yu. Popova M. N. 《Optics and Spectroscopy》2019,127(1):107-112
Optics and Spectroscopy - Luminescence spectra of single crystals of rare-earth gallium borates LnGa3(BO3)4 (Ln = Nd, Sm, Tb, Er, Dy, or Ho) at room (300 K) and cryogenic (10 K)... 相似文献
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Zhaketov V. D. Nikitenko Yu. V. Khaidukov Yu. N. Skryabina O. V. Csik A. Borisov M. M. Mukhamedzhanov E. Kh. Vdovichev S. N. Litvinenko E. I. Petrenko A. V. Churakov A. V. 《Journal of Experimental and Theoretical Physics》2019,129(2):258-276
Journal of Experimental and Theoretical Physics - The heterogeneous ferromagnetic–superconducting layered heterostructures V/Fe0.7V0.3/V/Fe0.7V0.3/Nb and Nb/Ni0.65(0.81)Cu0.35(0.19), which... 相似文献
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Pham Y. Yu Y. K. Manh T. V. Gamzatov A. Tartakovsky D. M. Yu S.-C. Yang D.-S. Kim D.-H. 《Physics of the Solid State》2020,62(5):845-850
Physics of the Solid State - Structural and magnetic properties of Sr-doped Pr0.7Ba0.3MnO3 polycrystallines prepared by solid state reaction are presented. Samples were in monoclinic structure... 相似文献
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JETP Letters - An Erratum to this paper has been published: https://doi.org/10.1134/S0021364022400028 相似文献
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A. A. Demidov D. V. Volkov I. A. Gudim E. V. Eremein V. L. Temerov 《Journal of Experimental and Theoretical Physics》2013,116(5):800-805
The magnetic properties of trigonal antiferromagnet SmFe3(BO3)4 are studied experimentally and theoretically. The measured characteristics are considered in terms of a theoretical approach based on the molecular field approximation and a crystal field model for a rare-earth ion. The temperature dependences of the initial magnetic susceptibility and the field and temperature dependences of magnetization in fields up to 5 T are described, and the anomaly in the magnetization curve for B ⊥ c near 1 T, which points to a first-order phase transition, is analyzed. 相似文献
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Atsuko Ito Keiko Iwai Chiyuki Oyama Setsu Morimoto Hiroaki Kato 《Hyperfine Interactions》1992,71(1-4):1371-1374
Magnetization and Mössbauer measurements have been made on a diluted antiferromagnets FexMg1?xTiO3 with x=0.2, 0.3 and 0.7. It has been demonstrated that this system exhibits a spin glass or a reentrant spin glass like behavior in the samples with x around the percolation concenrration xc≈0.25. It has been shown that various sizes of magnetic clusters are formed well above the transition temperatures determined by the magnetization measurements in the samples with x near xc. The behavior of Fe0.2Mg0.8TiO3 is discussed as a typical cluster glass. 相似文献
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The optical absorption spectra of single crystals of neodymium and samarium chromium borates are studied. A magnetic phase transition in NdCr3(BO3)4 (at T c = 8 ± 1 K) and SmCr3(BO3)4 (at T c = 5 ± 1 K) is observed. The effective magnetic field acting on the Nd3+ ion from the side of the ordered magnetic subsystem of chromium is estimated. 相似文献
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J. J. Larrea D. R. Sanchez F. J. Litterst E. M. Baggio-Saitovitch 《Hyperfine Interactions》2005,161(1-4):237-246
57Fe Mössbauer spectroscopic studies of iron ludwigite Fe3O2BO3 performed between 4 and 450 K allow the discussion of magnetic spin arrangements and the dynamics of electronic configurations of iron. The observed magnetic transitions are related to charge ordering. 相似文献
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Veselova S. V. Tereshina I. S. Verbetsky V. N. Karpenkov A. Yu. Savchenko A. G. 《Technical Physics》2020,65(7):1114-1122
Technical Physics - The composition, structure, and surface topology of as-cast, homogenized, and nitrogenized alloy based on an intermetallic compound Sm2Fe17 with partial substitution of samarium... 相似文献
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D. S. Rana C. M. Thaker K. R. Mavani J. H. Markna R. N. Parmar N. A. Shah D. G. Kuberkar S. K. Malik 《Hyperfine Interactions》2005,160(1-4):193-197
The effect of simultaneous increase in carrier density and size-disorder on the transport and magnetic properties of La0.7Ca0.3MnO3 has been investigated by studying the (La0.7 − 2x
Eu
x
)(Ca0.3Sr
x
)MnO3 (0.05 ≤ x ≤ 0.2) (LECSMO) compounds. These compounds have been compared with standard La1 − x
Ca
x
MnO3 (0.3 ≤ x ≤ 0.5) (LCMO) in which carrier density alone varies. In LECSMO, the insulator-metal transition temperature (T
p) decreases from 180 K for x = 0.05 to 80 K for x = 0.15 sample vis-à-vis ∼240 K for x = 0.35 to ∼225 K for x = 0.45 in LCMO system. Similarly, the Curie temperature (T
C) in LECSMO, decreases from 205 K for x = 0.05 to 75 K for x = 0.2 sample against 240 K for x = 0.35 to ∼220 K for x = 0.45 in LCMO system. Also, in LCMO the T
C and T
p are coincident whereas, in LECSMO system, with increasing x there is an increasing disparity between the two. At 5 K, in the metallic region, a large MR (>90%) is observed in x = 0.15 sample and is discussed in terms of phase segregation and inter-grain magnetoresistance. 相似文献