上海交通大学学报 ›› 2025, Vol. 59 ›› Issue (1): 131-138.doi: 10.16183/j.cnki.jsjtu.2023.112

• 材料科学与工程 • 上一篇    下一篇

室温磁致冷材料Mn5Ge2.7Zn0.3的相变、磁热效应和临界行为

许童杰1, 刘振华1, 金怀宇1, 刘结1, 蒋秀丽1, 李哲2, 刘永生1()   

  1. 1.上海电力大学 数理学院, 上海 200090
    2.曲靖师范学院 磁性材料及器件研究中心, 云南 曲靖 655011
  • 收稿日期:2023-03-28 修回日期:2023-05-22 接受日期:2023-05-29 出版日期:2025-01-28 发布日期:2025-02-06
  • 通讯作者: 刘永生,教授;E-mail: ysliu@shiep.edu.cn.
  • 作者简介:许童杰(1997—),硕士生,从事室温磁致冷工质、光纤光栅传感的研究.
  • 基金资助:
    国家自然科学基金项目(51971128);国家自然科学基金项目(52171185);上海市优秀学术/技术带头人项目(20XD1401800)

Phase Transition, Magnetocaloric Effect, and Critical Behavior of Room Temperature Magnetic Refrigerant Material Mn5Ge2.7Zn0.3

XU Tongjie1, LIU Zhenhua1, JIN Huaiyu1, LIU Jie1, JIANG Xiuli1, LI Zhe2, LIU Yongsheng1()   

  1. 1. College of Mathematics and Physics, Shanghai University of Electric Power, Shanghai 200090, China
    2. Center for Magnetic Materials and Devices, Qujing Normal University, Qujing 655011, Yunnan, China
  • Received:2023-03-28 Revised:2023-05-22 Accepted:2023-05-29 Online:2025-01-28 Published:2025-02-06

摘要:

通过电弧熔炼法成功制备了Mn5Ge2.7Zn0.3合金,并对其相变、磁热效应和临界行为等进行研究.利用热磁曲线确定了样品的居里温度为297.2 K,等温磁化曲线发现样品没有热滞,通过M2-H/M曲线和Banerjee准则证实样品经历了二级相变,进一步根据Maxwell方程计算样品的等温熵变,场-熵的幂律关系和归一化曲线也验证了二级相变.利用modified Arrott plot(MAP)法、Kouvel-Fisher(KF)法和等温磁化(CI)法求解临界指数,并用Widom标度定律和标度方程验证了临界指数的准确性.最后利用Arrott-Noaks方程对样品的临界行为进一步分析,归一化斜率和磁相互作用距离的分析证实了样品内部磁相互作用的复杂性.

关键词: Mn5Ge3基合金, 二级相变, 磁热效应, 临界行为, 相互作用

Abstract:

Mn5Ge2.7Zn0.3 alloy was successfully prepared by using the arc-melting method, and its phase transition, magnetocaloric effect, and critical behavior were studied. The thermomagnetic curve determined that the Curie temperature of the sample was 297.2 K, the isothermal magnetization curve found that the sample had no thermal hysteresis. The sample underwent a second-order phase transition through the M2-H/M plot and Banerjee’s criterion, and the isothermal entropy change of the sample was further calculated according to Maxwell’s equation, and the power-law relationship of field-entropy and the normalization curve also verified the fact of the second-order phase transition. The critical index was solved by the modified Arrott plot(MAP) method, the Kouvel-Fisher(KF) method and the critical isothermal (CI) method, and the accuracy of the critical index was verified by Widom scaling ansatz and scaling laws. Finally, the Arrott-Noaks equation was used to further analyze the critical behavior of the sample, and the normalization slope and magnetic interaction distance were analyzed to confirm the complexity of the magnetic interaction inside the sample.

Key words: Mn5Ge3 based alloys, second-order phase transition, magnetocaloric effect, critical behavior, interaction

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