Amorphous ferromagnetic CoSiB/Pd multilayer with perpendicular magnetic anisotropy

Abstract

Perpendicular magnetic anisotropy has been studied for possible use in high-density spin transfer torque magnetic random access memories. The key issues of high-density spin transfer torque magnetic random access memories are decreasing the switching current and have the high thermal stability. In order to solve these problems, the approach of developing a new amorphous ferromagnetic material for use as a pinned layer for a multilayer with a low saturated magnetization value has been suggested. In a previous study, amorphous ferromagnetic material CoSiB was shown to have a low saturated magnetization (M _s = 470 emu/cm³) and a modest anisotropy constant (K _u = 1,500 erg/cm³). Then, we investigated the perpendicular magnetic anisotropy of a [CoSiB t_CoSiB nm/Pt 1.4 nm]₅ multilayer, where tCoSiB are 0.1, 0.2, 0.3, 0.4, and 0.5 nm. In this study, we present a new multilayer type based on the previous study, and this multilayer, CoSiB/Pd multilayer has the perpendicular magnetic anisotropy. In this letter, we have investigated the perpendicular magnetic anisotropies of a [CoSiB t_CoSiB nm/Pd 1.3 nm]₅ multilayer, where tCoSiB are 0.1, 0.2, 0.3, 0.4, 0.5, and 0.6 nm and [CoSiB 6.3 nm/Pd t_Pd nm]₅ multilayer, where t _Pd are 1.1, 1.2, 1.3, 1.4, 1.5, and 1.6 nm.