Antiferromagnet Thickness Dependence and Rotatable Spins in Exchange Biased CoO/Fe Films
Antiferromagnet Thickness Dependence and Rotatable Spins in Exchange Biased CoO/Fe Films
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DOI：
10.1016/j.jmmm.2022.169898
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发表时间：
2022-09
影响因子：
2.7
通讯作者：
P. Greene;Yong Hu;Z. Qiu;Kai Liu
中科院分区：
文献类型：
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作者：
P. Greene;Yong Hu;Z. Qiu;Kai Liu
交换偏压和矫顽力增强的出现已经在具有不同反铁磁体（AF）厚度的外延 CoO/Fe 薄膜中进行了研究，甚至小于可检测到冻结 CoO 自旋的临界值。矢量磁力测量和一阶反转曲线 (FORC) 测量揭示了交换偏压和矫顽力增强对不同 CoO 厚度的依赖性，包括磁化反转从由于可旋转 CoO 力矩导致的高矫顽力、低偏压阶段到由于冻结 CoO 力矩而导致的高偏压、低矫顽力阶段的演变。 AF 域状态被发现是亚稳态的，可以在冻结自旋出现之前通过外部场和交换场重新定向，这表明了训练效果的一般起源。蒙特卡罗模拟表明，AF 各向异性能垒和磁场引起的可旋转自旋以及界面处的交换相互作用是造成观察到的效应的原因。
The emergence of exchange bias and coercivity enhancement has been investigated in epitaxial CoO/Fe films with varied antiferromagnet (AF) thicknesses, even smaller than the critical value where the frozen CoO spins are detectable. Vector magnetometry and first-order reversal curve (FORC) measurements reveal different CoO thickness dependence of the exchange bias and coercivity enhancement, including the evolution of magnetization reversal from a high coercivity, low bias phase due to rotatable CoO moments to a high bias, low coercivity phase due to frozen CoO moments. The AF domain state is found to be metastable, which can be reoriented by external and exchange fields prior to the appearance of frozen spins, pointing to a generic origin of the training effect. Monte Carlo simulations show that the AF anisotropy energy barrier and the rotatable spins induced by magnetic field and exchange interaction at the interface are responsible for the observed effects.