Interlayer exchange coupling between perpendicularly magnetized structures through a Ru/Ta composite spacer

Abstract

In stacks using a Ru/Ta composite spacer [Pt/Co](6)/Ru/Ta/CoFeB/MgO, both strong interlayer exchange coupling and perpendicular magnetic anisotropy are achieved. The composite spacer has the additional advantages of high post-annealing stability over a conventional Ru spacer; for a Ru (0.8 nm)/Ta (0.4 nm) spacer, where the antiparallel coupling is strongest, the coupling strength remains nearly constant at the highest annealing temperature of 375 degrees C. An interlayer exchange coupling is observed at very small Ru thicknesses down to 0.2 nm, which can be compared with the previous limit of 0.6 nm. (C) 2015 AIP Publishing LLC.