【摘要】 采用磁控溅射方法制备了以Pt为缓冲层和保护层的NiFe/FeMn薄膜。在NiFe/FeMn界面插入Pt,发现交换偏置场(Hex)随着插层Pt厚度(tPt)的增加而减小。一个重要的现象是当Pt插层厚度为0.4nm时,在Hex-tPt衰减曲线并非单纯指数下降,而是出现一个"凸起"。通过对样品磁矩随Pt插层厚度的变化规律进行分析,发现随Pt插层厚度的增加,样品的磁矩先逐渐增大,然后又有所下降,并且稳定在某一值;表明在样品制备过程中,NiFe与FeMn之间的相互作用(如界面反应),使得在NiFe/FeMn界面存在磁死层,Pt的插入抑制了NiFe/FeMn界面磁死层的产生,有利于交换耦合;另一方面,Pt的插入隔离了NiFe和FeMn的直接接触,使得FeMn对NiFe的钉扎作用减弱,不利于交换耦合。两个方面的共同作用,使得当Pt插层为某一合适厚度时,Hex-tPt曲线出现"凸起"。更多还原

【Abstract】 The Pt spacer,inserted between sputtered NiFe and FeMn layers,was deposited by magnetron sputtering.The influence of the Pt spacer in the NiFe/Pt/FeMn system on exchange coupling between NiFe and FeMn layers was studied.The results show that the geometry of the Pt spacer significantly affects the magnetic characteristics of the NiFe/Pt/FeMn system.For example,the exchange bias field(Hex)decreases with an increase of the Pt spacer thickness.Besides,a bump was observed in the non-exponential decay of the Hex-tpt,at a spacer thickness of 0.4 nm,where the magnetic moment maximizes.As the Pt layer thickness increases,the magnetic moment first increases,and then decreases,saturating at a certain Pt spacer thickness.Two possible reasons account for our observation.One is that the Pt layer eliminates the magnetically dead layer,usually resulted from reactions at the NiFe/FeMn interface,and favors the exchange coupling.The other is that insertion of Pt spacer isolates the NiFe layer and from the FeMn layer,weakening their exchange coupling.The combination of the two factors results in the bump observed at a Pt thickness of 0.4 nm.更多还原