中国物理B ›› 2002, Vol. 11 ›› Issue (6): 608-612.doi: 10.1088/1009-1963/11/6/317

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Magnetic phase transition and the corresponding magnetostriction of intermetallic compounds RMn2Ge2 (R=Sm, Gd)

郭光华1, 吴烨1, 张海贝1, D A Filippov2, R Z Levitin2, V V Snegirev2   

  1. (1)Department of Applied Physics, Central South University, Changsha 410083, China; (2)Department of Physics, M V Lomonosov Moscow State University, Moscow 119899, Russia
  • 收稿日期:2001-11-23 修回日期:2001-12-20 出版日期:2002-06-12 发布日期:2005-06-12
  • 基金资助:
    Project supported by the Scientific Research Foundation for the Returned Overseas Chinese Scholars, the National Education Ministry of China.

Magnetic phase transition and the corresponding magnetostriction of intermetallic compounds RMn2Ge2 (R=Sm, Gd)

Guo Guang-Hua (郭光华)a, Wu Ye (吴烨)a, Zhang Hai-Bei (张海贝)a, D A Filippovb, R Z Levitinb, V V Snegirevb   

  1. a Department of Applied Physics, Central South University, Changsha 410083, China; b Department of Physics, M V Lomonosov Moscow State University, Moscow 119899, Russia
  • Received:2001-11-23 Revised:2001-12-20 Online:2002-06-12 Published:2005-06-12
  • Supported by:
    Project supported by the Scientific Research Foundation for the Returned Overseas Chinese Scholars, the National Education Ministry of China.

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摘要： The temperature dependence of lattice constants a and c of intermetallic compounds RMn2Ge2 (R=Sm, Gd) is measured in the temperature range 10－800K by using the x-ray diffraction method. The magnetoelastic anomalies of lattice constants are found at the different kinds of spontaneous magnetic transitions. The transversal and longitudinal magnetostrictions of polycrystalline samples are measured in the pulse magnetic field up to 25T. In the external magnetic field there occurs a first-order field-induced antiferromagnetism－ferromagnetism transition in the Mn sublattice, which gives rise to a large magnetostriction. The magnitude of magnetostrictions is as large as 10-3. The transversal and longitudinal magnetostrictions have the same sign and are almost equal. This indicates that the magnetostriction is isotropic and mainly caused by the interlayer Mn－Mn exchange interaction. The experimental results are explained in the framework of a two-sublattice ferrimagnet with the negative exchange interaction in one of the sublattices by taking into account the lattice constant dependence of interlayer Mn－Mn exchange interaction.

Abstract: The temperature dependence of lattice constants a and c of intermetallic compounds RMn2Ge2 (R=Sm, Gd) is measured in the temperature range 10－800K by using the x-ray diffraction method. The magnetoelastic anomalies of lattice constants are found at the different kinds of spontaneous magnetic transitions. The transversal and longitudinal magnetostrictions of polycrystalline samples are measured in the pulse magnetic field up to 25T. In the external magnetic field there occurs a first-order field-induced antiferromagnetism－ferromagnetism transition in the Mn sublattice, which gives rise to a large magnetostriction. The magnitude of magnetostrictions is as large as 10-3. The transversal and longitudinal magnetostrictions have the same sign and are almost equal. This indicates that the magnetostriction is isotropic and mainly caused by the interlayer Mn－Mn exchange interaction. The experimental results are explained in the framework of a two-sublattice ferrimagnet with the negative exchange interaction in one of the sublattices by taking into account the lattice constant dependence of interlayer Mn－Mn exchange interaction.

Key words: rare-earth intermetallics, magnetic phase transition, magnetostriction

中图分类号:  (Magnetic phase boundaries (including classical and quantum magnetic transitions, metamagnetism, etc.))

  • 75.30.Kz
75.80.+q (Magnetomechanical effects, magnetostriction) 75.30.Et (Exchange and superexchange interactions) 61.66.Dk (Alloys )