Interfacial effects on magnetostriction of CoFeB/AlO_x/Co junction

摘要

Saturation magnetostriction (λ_s) of CoFeB/AlO_x/Co magnetic tunnel junctions (MTJs) has been measured. There are three kinds of MTJs in this study, i.e., glass/CoFeB(t_A)/AlO_x(δt_o)/Co(t_B) with t_A+t_B= 150 A; t_A= 100, 75, and 50 A; and δt_o=0-30 A. When plotting λ_s as a function of δt_o, the curve is concave up. We also investigated the compositional distribution of Fe, Al, and O across the tunneling part of the CoFeB(75 A)/AlO_x/Co(75 A) junction. Based on these results, we propose a model to describe how the total λ_s is affected by the CoFeB/AlO_x and AlO_x/Co interfaces.