CoFeB／Pt多层膜的垂直磁各向异性研究

摘要

The perpendicular magnetic anisotropy （PMA） in as-deposited [CoFeB/Pt]n multilayer is studied by using anomalous Hall effect. A clear PMA is observed in the ultrathin （- 0.5 nm） amorphous CoFeB layer sandwiched by Pt. The PMA in as-deposited [CoFeB/Pt]n multilayers is strongly dependent on the thicknesses of CoFeB, Pt, and the number of CoFeB/Pt bilayers. With the increase of the number of CoFeB/Pt bilayers （n ≥ 5）, the hysteresis loop changes from rectangular to bow-tie shaped, and then the net moment approaches to zero in the remnant state. Moreover, the coercivty of [CoFeB/Pt]n multilayers is much low, which meets the requirement for free perpendicular electrode in the future spintronic device.%具有垂直磁各向异性的磁性纳米结构是自旋转移力矩器件的重要研究内容，本文采用反常霍尔效应系统地研究了磁控溅射法制备的[CoFeB／Pt]。多层膜的垂直磁各向异性．当CoFeB的厚度小于0．6nm时，可以在[CoFeB／Pt]。多层膜中观察到清晰的垂直磁各向异性，其垂直磁各向异性强烈依赖于CoFeB和Pt层厚度及多层膜周期数．当多层膜周期数n≥5时，出现零剩磁现象．另外，[CoFeB／Pt]n多层膜的矫顽力均小于2kA．m-1，有望作为垂直自由层的重要侯选材料应用于垂直磁纳米结构中．