中国物理B ›› 2016, Vol. 25 ›› Issue (1): 16802-016802.doi: 10.1088/1674-1056/25/1/016802

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

Phase transition and critical behavior ofspin-orbital coupled spinel ZnV2O4

Li Wang(王理), Rong-juan Wang(王蓉娟), Yuan-yuan Zhu(朱媛媛), Zhi-hong Lu(卢志红),Rui Xiong(熊锐), Yong Liu(刘雍), Jing Shi(石兢)   

  1. 1. Key Laboratory of Artificial Micro-and Nano-structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan 430072, China;
    2. High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei 230031, China;
    3. School of Materials and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081, China
  • 收稿日期:2015-08-05 修回日期:2015-09-09 出版日期:2016-01-05 发布日期:2016-01-05
  • 通讯作者: Yong Liu, Jing Shi E-mail:yongliu@whu.edu.cn;jshi@whu.edu.cn
  • 基金资助:

    Project supported by the National Basic Research Program of China (Grant No. 2012CB821404), the National Natural Science Foundation of China (Grant Nos. 51172166 and 61106005), the National Science Fund for Talent Training in Basic Science, China (Grant No. J1210061), and the Doctoral Fund of Ministry of Education of China (Grant No. 20110141110007).

Phase transition and critical behavior ofspin-orbital coupled spinel ZnV2O4

Li Wang(王理)1, Rong-juan Wang(王蓉娟)1, Yuan-yuan Zhu(朱媛媛)2, Zhi-hong Lu(卢志红)3,Rui Xiong(熊锐)1, Yong Liu(刘雍)1, Jing Shi(石兢)1   

  1. 1. Key Laboratory of Artificial Micro-and Nano-structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan 430072, China;
    2. High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei 230031, China;
    3. School of Materials and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081, China
  • Received:2015-08-05 Revised:2015-09-09 Online:2016-01-05 Published:2016-01-05
  • Contact: Yong Liu, Jing Shi E-mail:yongliu@whu.edu.cn;jshi@whu.edu.cn
  • Supported by:

    Project supported by the National Basic Research Program of China (Grant No. 2012CB821404), the National Natural Science Foundation of China (Grant Nos. 51172166 and 61106005), the National Science Fund for Talent Training in Basic Science, China (Grant No. J1210061), and the Doctoral Fund of Ministry of Education of China (Grant No. 20110141110007).

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摘要：

We present the temperature-dependent susceptibility and specific heat measurement of spinel ZnV2O4. The structural transition with orbital ordering and the antiferromagnetic transition with spin ordering were observed at 50 K and 37 K, respectively. By analysis of the hysteresis behavior between the specific heat curves obtained in warming and cooling processes, the structural transition was confirmed to be the first-order transition, while the antiferromagnetic transition was found to be of the second-order type. At the structural transition, the latent heat and entropy change were calculated from the excess specific heat, and the derivative of pressure with respect to temperature was obtained using the Clausius-Clapayron equation. At the magnetic transition, the width of the critical fluctuation region was obtained to be about 0.5 K by comparing with Gaussian fluctuations. In the critical region, the critical behavior was analyzed by using renormalization-group theory. The critical amplitude ratio A+ /A-=1.46, which deviates from the 3D Heisenburg model; while the critical exponent α is -0.011, which is close to the 3D XY model. We proposed that these abnormal critical behaviors can be attributed to strong spin-orbital coupling accompanied with the antiferromagnetic transition. Moreover, in the low temperature range (2-5 K), the Fermi energy, the density of states near the Fermi surface, and the low limit of Debye temperature were estimated to be 2.42 eV, 2.48 eV-1, and 240 K, respectively.

关键词: spinel compounds, specific heat, phase transition, critical behavior

Abstract:

We present the temperature-dependent susceptibility and specific heat measurement of spinel ZnV2O4. The structural transition with orbital ordering and the antiferromagnetic transition with spin ordering were observed at 50 K and 37 K, respectively. By analysis of the hysteresis behavior between the specific heat curves obtained in warming and cooling processes, the structural transition was confirmed to be the first-order transition, while the antiferromagnetic transition was found to be of the second-order type. At the structural transition, the latent heat and entropy change were calculated from the excess specific heat, and the derivative of pressure with respect to temperature was obtained using the Clausius-Clapayron equation. At the magnetic transition, the width of the critical fluctuation region was obtained to be about 0.5 K by comparing with Gaussian fluctuations. In the critical region, the critical behavior was analyzed by using renormalization-group theory. The critical amplitude ratio A+ /A-=1.46, which deviates from the 3D Heisenburg model; while the critical exponent α is -0.011, which is close to the 3D XY model. We proposed that these abnormal critical behaviors can be attributed to strong spin-orbital coupling accompanied with the antiferromagnetic transition. Moreover, in the low temperature range (2-5 K), the Fermi energy, the density of states near the Fermi surface, and the low limit of Debye temperature were estimated to be 2.42 eV, 2.48 eV-1, and 240 K, respectively.

Key words: spinel compounds, specific heat, phase transition, critical behavior

中图分类号:  (Phase transitions and critical phenomena)

  • 68.35.Rh
75.40.-s (Critical-point effects, specific heats, short-range order) 64.60.-i (General studies of phase transitions) 82.60.Fa (Heat capacities and heats of phase transitions)