Restoration of bulk magnetic properties by strain engineering in epitaxial CoFe2O4 (001) ultrathin films

Abstract

We report on the significantly enhanced in-plane magnetic properties of CoFe2O4 (001) ultrathin layers (5 nm) grown on MgAl 2O4 (001) in comparison to films deposited on MgO (001). The predicted inverse spinel structure is confirmed by x-ray magnetic circular dichroism measurements and transmission electronic microscopy studies reveal a significant in-plane compressive strain, responsible for the strong film anisotropy. These results show that strain engineering can be used to tailor the magnetic properties of oxide ultrathin films. A large compressive strain restores bulk magnetic properties for CoFe2O4 films at tunnel barrier thicknesses. © 2011 American Institute of Physics.