LAUSR

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 Ni 50 Mn 34 In 16- x Fe x ( 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 H FC during field cooling and the maximum field H Max during 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 H FC and reducing H Max is 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Ni 50 Mn 34 In 16− x Fe x ( 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 H FC 和降 低 H Max 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.