MnNiGa体系中自旋亚稳态诱发的零场冷交换偏置  

Zero-field cooling exchange bias induced by spin metastable state in MnNiGa system

作　　者：李婕 高林[1] 邓姣姣 王祎 赵德伟 马丽[1] 齐世飞 甄聪棉[1] 侯登录[1] LI Jie;GAO Lin;DENG JiaoJiao;WANG Yi;ZHAO DeWei;MA Li;QI ShiFei;ZHEN CongMian;HOU DengLu(Hebei Advanced Thin Films Laboratory,College of Physics,Hebei Normal University,Shijiazhuang 050024,China)

机构地区：[1]河北师范大学物理学院河北省新型薄膜材料实验室,石家庄050024

出　　处：《中国科学：物理学、力学、天文学》2021年第6期131-139,共9页Scientia Sinica Physica,Mechanica & Astronomica

基　　金：国家自然科学基金(编号:51971087);河北省自然科学基金优青项目(编号:E2016205268)资助。

摘　　要：磁性材料中自旋亚稳态的存在往往会使体系中出现新奇的物理现象,例如磁跳变、变磁相变、斯格明子等.本文通过设计MnNiGa体系中Mn原子的占位,并基于第一性原理计算预期Mn_(2)Ni_(1.5)Ga_(0.5)中存在自旋亚稳态.由此选取Mn_(2)Ni_(2-x)Ga_(x)(x=0.36–0.60)为研究平台开展相关研究.实验结果显示,在Mn_(2)Ni_(1.5)Ga_(0.5)成分附近,晶格常数、晶轴比、直流和交流磁性测试均发生反常变化,并观测到零场冷交换偏置,表明了自旋亚稳态对结构和磁结构的双重影响,证明了自旋亚稳态对零场冷交换偏置的主导性作用.本工作为磁性材料中自旋亚稳态的设计提供了新思路,为零场冷交换偏置体系的实现提供了新方法.The existence of the spin metastable state in magnetic materials often causes novel physics including magnetization jumps, metamagnetic transition, and skyrmions. In this paper, we design the occupancy of Mn atoms in the Mn Ni Ga system, and based on first-principles calculations, we anticipate the existence of spin metastable state in Mn_(2)Ni_(1.5)Ga_(0.5).Therefore, Mn_(2)Ni_(2-x)Ga_(x)(x=0.36–0.60) is selected as the research platform to carry out related research. The experimental results show that near the composition of Mn_(2)Ni_(1.5)Ga_(0.5), the lattice constant, crystal axis ratio, DC and AC magnetic test all have abnormal changes, and the zero-field cooling exchange bias is observed, which indicates the dual effects of the spin metastable state on structure and magnetic structure, and proves the dominant effect of spin metastable state on zerofield cooling exchange bias. This work provides a new idea for the design of spin metastable states in magnetic materials,and a new method for the realization of a zero-field cold exchange bias system.

关 键 词：Heusler化合物 自旋亚稳态 零场冷交换偏置 

分 类 号：O469[理学—凝聚态物理]