铁磁/反铁磁双层膜中交换偏置及矫顽场的温度特性研究(英文)

Temperature Dependence of Exchange Bias and Coercivity in Ferromagnetic Layer Coupled with Antiferromagnetic Layer

讨论了铁磁 反铁磁双层膜中交换偏置和矫顽场随温度变化的关系。在本模型中 ,温度的依赖性来源于系统态的热激发以及相关磁学参量的温度依赖性。数值结果显示 :低温下 ,交换偏置和矫顽场随温度的升高而减少 ,但是随着界面的交换耦合的增强或铁磁层各向异性的减少 ,其交换偏置变得平坦。随着温度的升高 ,交换偏置减少直至零 ;而矫顽场却达到峰值后再减为零。这些结果与实验结果定性一致。根据数值计算结果 ,可以预见软的铁磁层耦合上硬的反铁磁层 ,在恰当的交换耦合强度下 ,可构建具有大的交换偏置、小矫顽场 ;

The temperature dependence of exchange bias and coercivity of ferromagnetic layer and antiferromagnetic gain layer was discussed. In this model, the temperature dependence comes from the thermal instability of the system state and the temperature modulated relative magnetic parameters. These numerical results show that, at low temperature, the exchange bias and the coercivity decrease with increasing temperature, but the exchange bias becomes flat with increasing interface exchange coupling or decreasing ferromagnetic anisotropy. However, at high temperature the exchange bias becomes zero while the coercivity reach a peak, which are in good agreement with experimental results qualitatively. Based on our discussion, we can conclude that a soft ferromagnetic layer coupled by a hard antiferromagnetic layer with special exchange coupling may be very applicable to design magnetic devices, which have high exchange bias and low coercivity and are almost independent of temperature.