Effects of Co addition on magneto-transport properties of magnetic tunnel Junction consisting of CoFeB or CoFeSiB free layer

摘要

Amorphous ferromagnetic CoFeB and CoFeSiB layers with various Co concentrations were employed as free layers of magnetic tunnel junctions (MTJs), and their magnetization switching performances were compared. Both analytical measurements and micromagnetic modeling efforts were carried out to understand the dependence of magnetization switching field (H_(sw)) on Co concentration. In overall, the CoFeSiB free layered MTJs showed a lower H_(sw) compared to that of the CoFeB ones. This is due to the fact that CoFeSiB possesses a lower saturation magnetization than CoFeB and, moreover, its magnetization switching process shows coherent switching.