Griffiths phase arising from local lattice distortion and spin glass above the Curie temperature in Ni 2 MnSb polycrystalline Heusler alloy

作者：Fanghua Tian, Qizhong Zhao, Jiale Guo, Yin Zhang, Minxia Fang, Tieyan Chang, Zhiyong Dai, Chao Zhou, Kaiyan Cao, Sen Yang · 发表于：Physical review. B./Physical review. B · 年份：2024 · DOI：10.1103/physrevb.109.224405 · 被引用次数：11 · 研究领域：Heusler alloys: electronic and magnetic properties、Shape Memory Alloy Transformations、Advanced Thermoelectric Materials and Devices

In this work, the phenomenon of downward deviations from the Curie-Weiss law is found above the Curie temperature (329--458 K) in ${\mathrm{Ni}}_{2}\mathrm{MnSb}$ polycrystalline Heusler alloy, and it was confirmed by the change in inverse magnetic susceptibility under different magnetic fields that it is the Griffiths phase. This abnormal phenomenon can be attributed to short-range nanoferromagnetic clusters caused by local lattice distortion within the paramagnetic state. The ac magnetic susceptibility further showed characteristics of long-range disordered and short-range ordered glassy magnetic states in Griffiths phase range, where the magnetization intensity of the spin glass state has a frequency dependence. This work revealed the nature of the Griffiths phase in Heusler alloys and observed the characteristics of spin glass at high temperatures, providing experimental evidence and support for the study of high-temperature spintronics.