Tuning the magnetic properties of V2O3/CoFeB heterostructures across the V2O3 structural transition

Abstract

In this work, we investigate the effects of the ${\mathrm{V}}_{2}{\mathrm{O}}_{3}$ structural phase transition on the magnetic properties of an amorphous magnetic thin film of CoFeB in contact with it. ${\mathrm{V}}_{2}{\mathrm{O}}_{3}$ thin films are deposited epitaxially on sapphire substrates, reaching bulklike properties after few nm of growth. By means of temperature dependent Kerr effect characterizations, we prove that crossing the ${\mathrm{V}}_{2}{\mathrm{O}}_{3}$ structural phase transition induces reproducible and reversible changes to CoFeB magnetic properties, especially to its coercive field. By decreasing the oxide layer thickness, its effects on the magnetic layer decreases, while reducing the magnetic layer thickness maximizes it, with a maximum of 330% coercive field variation found between the two ${\mathrm{V}}_{2}{\mathrm{O}}_{3}$ structural phases. By simply tuning the temperature, this systematic study shows that the engineering of ${\mathrm{V}}_{2}{\mathrm{O}}_{3}$ structural transition induces large interfacial strain and thus strong magnetic property variations to an amorphous thin film, opening wide possibilities in implementing strain-driven control of the magnetic behavior without strict requirements on epitaxial coherence at the interface.