中国物理B ›› 2016, Vol. 25 ›› Issue (9): 96107-096107.doi: 10.1088/1674-1056/25/9/096107

• CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES • 上一篇    下一篇

Influence of Tb on easy magnetization direction and magnetostriction of ferromagnetic Laves phase GdFe2 compounds

Adil Murtaza, Sen Yang(杨森), Chao Zhou(周超), Xiaoping Song(宋晓平)   

  1. School of Science, MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, State Key Laboratory for Mechanical Behaviour of Materials, Xi'an Jiaotong University, Xi'an 710049, China
  • 收稿日期:2016-03-30 修回日期:2016-05-03 出版日期:2016-09-05 发布日期:2016-09-05
  • 通讯作者: Adil Murtaza E-mail:adil.xjtu@gmail.com
  • 基金资助:

    Project supported by the National Basic Research Program of China (Grant No. 2012CB619401).

Influence of Tb on easy magnetization direction and magnetostriction of ferromagnetic Laves phase GdFe2 compounds

Adil Murtaza, Sen Yang(杨森), Chao Zhou(周超), Xiaoping Song(宋晓平)   

  1. School of Science, MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, State Key Laboratory for Mechanical Behaviour of Materials, Xi'an Jiaotong University, Xi'an 710049, China
  • Received:2016-03-30 Revised:2016-05-03 Online:2016-09-05 Published:2016-09-05
  • Contact: Adil Murtaza E-mail:adil.xjtu@gmail.com
  • Supported by:

    Project supported by the National Basic Research Program of China (Grant No. 2012CB619401).

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摘要：

The crystal structure, magnetization, and spontaneous magnetostriction of ferromagnetic Laves phase GdFe2 compound have been investigated. High resolution synchrotron x-ray diffraction (XRD) analysis shows that GdFe2 has a lower cubic symmetry with easy magnetization direction (EMD) along [100] below Curie temperature TC. The replacement of Gd with a small amount of Tb changes the EMD to [111]. The Curie temperature decreases while the field dependence of the saturation magnetization (Ms) measured in temperature range 5-300 K varies with increasing Tb concentration. Coercivity Hc increases with increasing Tb concentration and decays exponentially as temperature increases. The anisotropy in GdFe2 is so weak that some of the rare-earth substitution plays an important role in determining the easy direction of magnetization in GdFe2. The calculated magnetostrictive constant λ100 shows a small value of 37×10-6. This value agrees well with experimental data 30×10-6. Under a relatively small magnetic field, GdFe2 exhibits a V-shaped positive magnetostriction curve. When the field is further increased, the crystal exhibits a negative magnetostriction curve. This phenomenon has been discussed in term of magnetic domain switching. Furthermore, magnetostriction increases with increasing Tb concentration. Our work leads to a simple and unified mesoscopic explanation for magnetostriction in ferromagnets. It may also provide insight for developing novel functional materials.

关键词: crystal structure, magnetic anisotropy, lattice distortion, magnetostriction

Abstract:

The crystal structure, magnetization, and spontaneous magnetostriction of ferromagnetic Laves phase GdFe2 compound have been investigated. High resolution synchrotron x-ray diffraction (XRD) analysis shows that GdFe2 has a lower cubic symmetry with easy magnetization direction (EMD) along [100] below Curie temperature TC. The replacement of Gd with a small amount of Tb changes the EMD to [111]. The Curie temperature decreases while the field dependence of the saturation magnetization (Ms) measured in temperature range 5-300 K varies with increasing Tb concentration. Coercivity Hc increases with increasing Tb concentration and decays exponentially as temperature increases. The anisotropy in GdFe2 is so weak that some of the rare-earth substitution plays an important role in determining the easy direction of magnetization in GdFe2. The calculated magnetostrictive constant λ100 shows a small value of 37×10-6. This value agrees well with experimental data 30×10-6. Under a relatively small magnetic field, GdFe2 exhibits a V-shaped positive magnetostriction curve. When the field is further increased, the crystal exhibits a negative magnetostriction curve. This phenomenon has been discussed in term of magnetic domain switching. Furthermore, magnetostriction increases with increasing Tb concentration. Our work leads to a simple and unified mesoscopic explanation for magnetostriction in ferromagnets. It may also provide insight for developing novel functional materials.

Key words: crystal structure, magnetic anisotropy, lattice distortion, magnetostriction

中图分类号:  (Crystallographic aspects of phase transformations; pressure effects)

  • 61.50.Ks
75.60.Ej (Magnetization curves, hysteresis, Barkhausen and related effects) 75.30.Gw (Magnetic anisotropy) 75.80.+q (Magnetomechanical effects, magnetostriction)