Rui W B, Hu Y, Du A, You B, Xiao M W, Zhang W, Zhou S M, Du J
National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, P. R. China.
College of Sciences, Northeastern University, Shenyang, 110819, P. R. China.
Sci Rep. 2015 Sep 8;5:13640. doi: 10.1038/srep13640.
We report on the experimental and theoretical studies of cooling field (HFC) and temperature (T) dependent exchange bias (EB) in FexAu1-x/Fe19Ni81 spin glass (SG)/ferromagnet (FM) bilayers. When x varies from 8% to 14% in the FexAu1-x SG alloys, with increasing T, a sign-changeable exchange bias field (HE) together with a unimodal distribution of coercivity (HC) are observed. Significantly, increasing in the magnitude of HFC reduces (increases) the value of HE in the negative (positive) region, resulting in the entire HE∼T curve to move leftwards and upwards. In the meanwhile, HFC variation has weak effects on HC. By Monte Carlo simulation using a SG/FM vector model, we are able to reproduce such HE dependences on T and HFC for the SG/FM system. Thus this work reveals that the SG/FM bilayer system containing intimately coupled interface, instead of a single SG layer, is responsible for the novel EB properties.
我们报道了关于FexAu1-x/Fe19Ni81自旋玻璃（SG）/铁磁体（FM）双层膜中冷却场（HFC）和温度（T）依赖的交换偏置（EB）的实验和理论研究。当FexAu1-x SG合金中的x从8%变化到14%时，随着T升高，观察到一个可改变符号的交换偏置场（HE）以及矫顽力（HC）的单峰分布。值得注意的是，HFC大小的增加会降低（增加）负（正）区域中HE的值，导致整个HE∼T曲线向左上方移动。同时，HFC变化对HC的影响较弱。通过使用SG/FM矢量模型的蒙特卡罗模拟，我们能够重现SG/FM系统中HE对T和HFC的这种依赖性。因此，这项工作表明，包含紧密耦合界面的SG/FM双层系统，而非单个SG层，是导致这种新型EB特性的原因。
