CoFeB/IrMn/Fe交换偏置三层膜中CoFeB层的磁特性

Magnetic properties of CoFeB layer in CoFeB/IrMn/Fe exchange bias trilayers

采用磁控溅射镀膜方法制备了非晶CoFeB单层膜及CoFeB/Ir Mn/Fe三层膜。利用XRD进行了物相分析和结构表征,确定了Ir Mn和Fe的生长取向以及二者的外延关系。研究单层CoFeB薄膜翻转场和剩磁比与外磁场的关系,发现其具有微弱的单轴磁各向异性。研究表明三层膜结构中的CoFeB薄膜具有不同类型的磁滞回线,包括带有偏置的矩形和两步台阶状的磁滞回线及没有偏置的两步台阶状的磁滞回线。用90°畴壁成核与位移模型可以很好地拟合三层膜结构中CoFeB层与Fe层的磁化翻转场与外加磁场的角度关系,发现CoFeB层磁各向异性的转变源于界面的交换耦合作用。

The amorphous CoFeB single-layer film and Co FeB/IrMn/Fe trilayers were prepared by magnetron sputtering coating method.The phase analysis and structure characterization were carried out by XRD,determined the growth orientation of IrMn and Fe,and the epitaxial relationship between IrMn and Fe.The angular dependence of switching field and remanence ratio of the single-layer CoFeB film shows that it has a weak uniaxial magnetic anisotropy.The study indicates that the CoFeB film in the trilayers film structure has different types of hysteresis loops,including biased square hysteresis loops,biased two-step hysteresis loops,unbiased two-step hysteresis loops.The 90°wall nucleation and propagation model can well fit the relationship between the magnetization switching field of the CoFeB layer and Fe layer in the trilayers film structure with the external magnetic field,it is found that the transition of the magnetic anisotropy of the CoFeB layer is induced by the interface exchange coupling.