不同底层对CoFeB/Pt多层膜垂直磁各向异性的影响研究

Perpendicular magnetic anisotropy in CoFeB/Pt multilayers with different underlayers

采用磁控溅射方法在玻璃基片上制备了以Ru,Cu,Pt和Ta为底层的Co Fe B/Pt多层膜样品,研究了各底层对Co Fe B/Pt多层膜的反常霍尔效应的影响。发现Ru和Cu作为Co Fe B/Pt多层膜的底层在保持样品的垂直磁各向异性方面的作用远不如Pt和Ta底层,而且样品的霍尔电阻比Pt和Ta做底层要小。Ta作为Co Fe B/Pt多层膜的底层与Pt作为底层相比能够更好地和多层膜晶格匹配,并且在400℃退火后反常霍尔效应得到增强。霍尔电阻提高近80%,矫顽力达到了5.7×10~3 A·m^(–1),有望作为垂直自由层应用到磁隧道结构中。

The impact of different underlayers such as Ru, Cu, Pt and Ta on anomalous Hall effect of Co Fe B/Pt multilayers was investigated. The samples were successfully manufactured by magnetron sputtering technique on the glass substrate. Pt and Ta underlayer plays a much greater role in maintaining the PMA of samples, compared with Ru and Cu underlayer. The Hall resistance of Ru and Cu underlayer samples is smaller than that of Ta and Pt underlayer samples. Ta underlayer has less lattice mismatcha to Co Fe B/Pt multilayers than the Pt underlayer, and the perpendicular magnetic anisotropy is enhanced even after annealing at 400 ℃. The Hall resistance is increased by nearly 80%, and the coercive force reaches 5.7×10^3 A·m^（–1）. It is expected to be applied to the magnetic tunnel structure as a vertical free layer in the future.