Tunable perpendicular magnetic anisotropy in epitaxial Y3Fe5O12 films

Abstract

High quality epitaxial (111) Y3Fe5O12 (YIG) films are fabricated by annealing amorphous precursor films that are sputtering deposited on three kinds of single crystal garnet substrates with lattice constants exceeding that of YIG by a ratio from 0.76% to 1.58%. The effective perpendicular magnetic anisotropy (PMA) in the YIG films is significantly altered by the epitaxial strain induced magnetoelastic anisotropy. Large PMA is demonstrated in the fully strained thin YIG films on substrates with lattice mismatch from 1.05% to 1.58% due to the overwhelming of the magnetoelastic anisotropy. Less-strained YIG films, corresponding to partial strain relaxation at larger YIG thickness or smaller substrate lattice mismatch at 0.76%, show substantial but insufficient magnetoelastic anisotropy to overcome shape anisotropy. Magnetotransport characterization on YIG/Pt bilayers shows that the surface of YIG with either in-plane or perpendicular magnetization allows efficient equilibrium and/or nonequilibrium spin interexchange across the heterostructure interface.