Effect of Ta capping layer on the magnetic coupling oscillation of L10-MnGa/Co/Ta films

Abstract

The magnetic exchange interactions between L10-MnGa and ultrathin Co film with Ta capping layer were studied using the first-principles calculations. An oscillation of magnetic coupling from antiferromagnetic (AFM) to ferromagnetic (FM) couplings was observed with increasing the thickness of Co layers. The oscillation period is two monolayers, which was attributed to the quantum well states mainly confined in the Co layers. The appearance of AFM and FM states of L10-MnGa/Co/Ta correspond to the odd and even number of Co layers, respectively. In contrast, the oscillation was completely reversible with that in L10-MnGa/Co without Ta layers, clearly indicating Ta capping layers strongly affect magnetic coupling behavior between L10-MnGa and Co. The related mechanism was discussed by analyzing the spin resolved energy bands and charge densities. The results are useful to understand the magnetic coupling interactions and the confinement behavior of spin electrons in multilayer films, benefiting to develop new magnetic nanostructures.