基于CoFe/Pd的自旋阀底电极中增强的垂直磁各向异性

Enhanced perpendicular magnetic anisotropy in CoFe/Pd based bottom electrode of spin valves

采用磁控溅射方法制备了Pd(3nm)/CoFe(0.8nm)/纳米氧化层/CoFe(t nm)/Cu(4nm)/Pd(5nm)自旋阀底电极薄膜,并用振动样品磁强计对样品的磁性能进行了测量.研究结果表明:纳米氧化层的引入可以使电极薄膜的磁各向异性在退火后从面内转到垂直膜面方向,并且这种强烈的垂直磁各向异性在CoFe有效厚度为2nm时仍能保持.这种具有非多层膜结构、铁磁层较厚、热稳定性较高的底电极有利于基于自旋转移矩的垂直磁各向异性全金属赝自旋阀的发展.

A bottom electrode structure of spin valves （SVs） is reported, the film prepared by the magnetron sputtering method stacks Pd（3 nm）/CoFe（0.8 nm）/native oxide/CoFe（t nm）/Cu（4 nm）/Pd（5 nm）. The magnetic properties of the film are measured by vibrating sample magnetometer （VSM）. The results indicate that the magnetic anisotropy of the film has been transformed from in-plane to out-of-plane after annealing, and the strong perpendicular magnetic anisotropy （PMA） is still presented even for the film with effective CoFe thickness as large as 2 nm. This kind of bottom electrode film with non-multilayer structure, thick ferromagnetic layer and high thermal stability is beneficial to the development of the spin transfer torque all-metal pseudo-spin-valves with perpendicular magnetic anisotropy.