Temperature dependent exchange bias training effect in single-crystalline BiFeO3/Co bilayers
Temperature dependent exchange bias training effect in single-crystalline BiFeO3/Co bilayers
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DOI：
10.1063/1.4917465
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发表时间：
2015-04
影响因子：
3.2
通讯作者：
M. He;B. You;H. Tu;Y. Sheng;Qingyu Xu;W. Rui;Yajun Gao;Yongjun Zhang;Yongbing Xu;J. Du
中科院分区：
文献类型：
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作者：
M. He;B. You;H. Tu;Y. Sheng;Qingyu Xu;W. Rui;Yajun Gao;Yongjun Zhang;Yongbing Xu;J. Du
采用脉冲激光沉积和磁控溅射相结合的方法在（001）SrTiO 3衬底上制备了BiFeO 3（BFO）/Co双层薄膜。在5 ~ 300 K温度范围内，研究了交换偏置（EB）和伴随的训练效应随温度（T）的变化。在100 K以下，交换场呈现非单调的变化，且变化幅度急剧增大。同时，当T < 100 K时，记录到较强的训练效应，当T增加到300 K时，训练效应单调减弱。这些温度相关的EB和训练效应可能是由低温下界面自旋玻璃（SG）相和高温下反铁磁BFO层中的未补偿自旋引起的。低温电子束训练的结果可以很好地拟合修正Binek的模型，考虑到钉扎SG自旋在下降和上升分支的不对称变化。
Single-crystalline BiFeO3 (BFO)/Co bilayers were prepared by combined pulsed laser deposition and magnetron sputtering on (001) SrTiO3 substrates. Exchange bias (EB) and accompanying training effect have been studied as a function of temperature (T) between 5 K and 300 K. A non-monotonic exchange field variation with sharp increase below 100 K has been observed. In the meanwhile, strong training effect was recorded when T < 100 K and it weakens monotonically with increasing T up to 300 K. These temperature dependent EB and training effect may be caused by the uncompensated spins in both the interfacial spin-glass (SG) phase at low temperature and the antiferromagnetic BFO layer at higher temperature. The low temperature EB training results can be well fitted by a modified Binek's model considering asymmetric changes of the pinning SG spins at the descending and the ascending branches.