Perpendicular Magnetic Anisotropy and Interfacial Dzyaloshinskii-Moriya Interaction in Pt/CoFeSiB Structures

Abstract

Magnetic materials exhibiting perpendicular magnetic anisotropy (PMA) have an important role in the development of high-density magnetic random-access memory and domain-wall devices. Exotic physical phenomena result from spin-orbit coupling, such as PMA and the interfacial Dzyaloshinskii-Moriya interaction (iDMI), at interfaces between nonmagnetic (NM) and ferromagnetic (FM) materials. We report on the NM Pt thickness dependence of PMA and iDMI in Ta/Pt/CoFeSiB/Ta films and the MgO thickness dependence of PMA in Ta/Pt/CoFeSiB/MgO/Ta films. We selected amorphous FM CoFeSiB because of its lower saturation magnetization (560 eμcm3) than that of Co or CoFeB, which may be beneficial for lowering the current density for switching. All samples were deposited by dc magnetron sputtering and annealed at 300 °C for 1 h. The Ta(3)/Pt(5)/CoFeSiB(1.5)/Ta(5) (nm) film exhibited PMA in the as-deposited state as well as after heat treatment. This structure possessed an iDMI energy density of 0.386 mJ/m2. © 2010-2012 IEEE.