Abstract

This work shows the dynamics of the process of the magnetization reversal of a thin film of the Heusler alloy Co₂FeSi in the stack of a multilayer structure with a magnetic tunneling junction that has a tunnel magnetoresistance (TMR) of 149%. Using the method of a magneto-optical indicator film, the process of magnetization reversal of this layer is visualized. Anisotropy of the magnetization reversal of the Co₂FeSi layer under the action of in-plane magnetic fields is found. The behavior of the magnetization reversal under the action of fields applied perpendicular to the easy axis of the induced anisotropy indicates smooth, coherent rotation of the magnetic moment from the easy axis towards the applied field. As the external field is directed along the easy axis, a complex domain structure appears and its asymmetric nucleation and movement are observed. The domains propagate and move depending on the direction of the field, when the external field is directed along the easy axis. For example, when the field is antiparallel to the direction of the easy axis of the free layer, domains nucleate at the edges of the film and propagate inward. The magnetization of the free layer becomes antiparallel to the magnetization of the upper layer of the synthetic antiferromagnetic film (IrMn/CoFe/Ru/CoFeB). When the field is switched to the opposite direction, domains originate inside the film and propagate to its edges to transfer the magnetization of the free layer to a parallel position to the reference layer. These results are important for improving the quality of Heusler-alloy-based magnetic tunneling junction devices.

中文翻译：

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Heusler 合金交换耦合合成反铁磁体的磁化反转动力学

摘要

_{这项工作显示了 Heusler 合金 Co 2} FeSi薄膜在具有 149% 隧道磁阻 (TMR) 的磁隧道结的多层结构堆叠中的磁化反转过程的动力学。使用磁光指示膜的方法，可视化该层的磁化反转过程。_{Co 2}的磁化反转的各向异性发现了面内磁场作用下的 FeSi 层。在垂直于感应各向异性的易轴施加的场的作用下磁化反转的行为表明磁矩从易轴到施加场的平滑、相干旋转。由于外场沿易轴方向，出现了复杂的畴结构，并观察到其不对称的成核和运动。当外部场沿易轴定向时，域根据场的方向传播和移动。例如，当场与自由层的易轴方向反平行时，畴在薄膜边缘成核并向内传播。自由层的磁化变得与合成反铁磁膜（IrMn/CoFe/Ru/CoFeB）的上层的磁化反平行。当场切换到相反方向时，畴起源于薄膜内部并传播到其边缘，以将自由层的磁化转移到与参考层平行的位置。这些结果对于提高基于 Heusler 合金的磁性隧道结器件的质量具有重要意义。