织构和界面粗糙度对NiFe/FeMn双层膜交换偏置场的影响

Effect of texture and interfacial roughness on the exchange bias field of NiFe/FeMn films

采用磁控溅射方法制备NiFe/FeMn双层膜 (分别以Ta、Cu作为缓冲层 ,Ta作为保护层 )。实验发现 ,以Ta为缓冲层的NiFe/FeMn双层膜的交换偏置场比以Cu为缓冲层的NiFe/FeMn双层膜的交换偏置场大 ,而矫顽力却很小。我们从织构、界面粗糙度两方面对其中的原因进行了分析。以Ta为缓冲层的NiFe/FeMn双层膜有好的织构且NiFe/FeMn界面较平滑 ,这引起了较强的交换偏置场和较低的矫顽力。

The NiFe/FeMn bilayers with different buffer layers (Ta or Cu) and Ta cover layers were prepared by magnetron sputtering. The results showed that the exchange bias field of NiFe/FeMn films with the Ta buffer was higher than that of the films with the Cu buffer, but the coercivity of former was lower than that of later. We analysed the reasons by studying the crystallographic texture and interfacial roughness. The Ta buffer promoted the formation of the strongly (111) texture and smooth interface, which results in the strong exchange bias field and low coercivity.