Extra large unidirectional anisotropy constant of Co–Fe/Mn–Ir bilayers with ultra-thin antiferromagnetic layer

Abstract

Unidirectional anisotropy constant, J K, of Co 1− x Fe x /Mn–Ir bilayer was investigated as a function of the Fe concentration, x. As a result, we obtained an extra large value of J K, which exceeds 0.5 erg/cm 2, at x=0.3–0.4 with the ultra-thin (50–100 Å) Mn–Ir layer. The blocking temperature of Co 0.7Fe 0.3 40 Å/Mn–Ir 100 Å bilayer was 290°C, which is sufficiently high for the application of spin valve giant magnetoresistive devices.