Large exchange bias in magnetic shape memory alloys by tuning magnetic ground state and magnetic-field history  

基于磁性形状记忆合金磁基态和磁场历史调控的大交换偏置效应

作　　者：Xiaoqi Liao Lumei Gao Yu Wang Xin Xu Tahir Khan Muhammad Tieyan Chang Kaiyun Chen Yu-Jia Zeng Sen Yang Svedlindh Peter 廖晓奇;高禄梅;王宇;徐鑫;Muhammad Tahir Khan;常铁严;陈凯运;曾昱嘉;杨森;Peter Svedlindh(MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter and State Key Laboratory for Mechanical Behavior of Materials,Xi’an Jiaotong University,Xi’an 710049,China;College of Physics and Optoelectronic Engineering,Shenzhen University,Shenzhen 518060,China;Instrument Analysis Center,Xi’an Jiaotong University,Xi’an 710049,China;Faculty of Engineering and Applied Sciences,Department of Physics,RIPHAH International University I-14 Campus,Islamabad,Pakistan;Solid State Physics,Department of Engineering Sciences,Ångström Laboratory,Uppsala University,75121 Uppsala,Sweden)

机构地区：[1]MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter and State Key Laboratory for Mechanical Behavior of Materials,Xi’an Jiaotong University,Xi’an 710049,China [2]College of Physics and Optoelectronic Engineering,Shenzhen University,Shenzhen 518060,China [3]Instrument Analysis Center,Xi’an Jiaotong University,Xi’an 710049,China [4]Faculty of Engineering and Applied Sciences,Department of Physics,RIPHAH International University I-14 Campus,Islamabad,Pakistan [5]Solid State Physics,Department of Engineering Sciences,Ångström Laboratory,Uppsala University,75121 Uppsala,Sweden

出　　处：《Science China Materials》2020年第7期1291-1299,共9页中国科学（材料科学（英文版）

基　　金：supported by the National Natural Science Foundation of China(51471127,51431007 and 51371134);the Program for Young Scientific New-star in Shaanxi Province of China(2014KJXX-35);the Innovation Capability Support Program of Shaanxi(2018PT-28 and 2017KTPT-04);Shenzhen Science and Technology Project(JCYJ20180507182246321);the Fundamental Research Funds for Central Universities of China。

摘　　要：The exchange bias is of technological significance in magnetic recording and spintronic devices.Pursuing a large bias field is a long-term goal for the research field of magnetic shape memory alloys.In this work,a large bias field of 0.53 T is achieved in the Ni50Mn34In16-xFex(x=1,3,5)system by tuning the magnetic ground state(determined by the composition x)and the magnetic-field history(determined by the magnetic field HFCduring field cooling and the maximum field HMaxduring isothermal magnetization).The maximum volume fraction of the interfaces between the ferromagnetic clusters and antiferromagnetic matrix and the strong interfacial interaction are achieved by tuning the magnetic ground state and the magnetic-field history,which results in strong magnetic unidirectional anisotropy and the large exchange bias.Moreover,two guidelines were proposed to obtain the large bias field.Firstly,the composition with a magnetic ground state consisting of the dilute spin glass and the strong antiferromagnetic matrix is preferred to obtain a large bias field;secondly,tuning the magnetic-field history by enhancing HFCand reducing HMaxis beneficial to achieving large exchange bias.Our work provides an effective way for designing magnetically inhomogeneous compounds with large exchange bias.由于交换偏置效应对磁记录和自旋电子器件的重要意义,在磁性形状记忆合金中获得大偏置场一直是人们长期努力的目标.本文通过调控Ni50Mn34In16-xFex(x=1,3,5)磁性形状记忆合金的磁性基态(取决于合金成分)和磁场历史(取决于冷却过程中冷却场HFC和等温磁化过程中所施加的最大测试场HMax),对交换偏置行为进行了系统研究.结果表明,调控磁性基态和磁场历史可以获得最大铁磁簇与反铁磁基体界面体积分数以及它们之间的强相互作用,从而诱发了界面上强单向各向异性,产生了大交换偏置场.本文提出了获得大交换偏置场需要遵循的两条原则.首先,选择稀磁自旋玻璃与强反铁磁基体的磁性基态成分可获得大交换偏置场;其次,通过增强HFC和降低HMax有利于实现大交换偏置.本研究为设计具有大交换偏置场的非均匀磁性相化合物提供了一种有效的方法.

关 键 词：magnetic shape memory alloys MARTENSITE exchange bias spin glass ANTIFERROMAGNETIC 

分 类 号：TG139.6[一般工业技术—材料科学与工程]