Origin of the butterfly-shaped magnetoresistance in reactive sputtered epitaxial Fe3O4 films

Abstract

Epitaxial Fe3O4 thin films were synthesized by facing-target reactive sputtering Fe targets. The epitaxy of the Fe3O4 film on MgO (100) was examined macroscopically using x-ray diffraction, including conventional θ-2θ scan, tilting 2θ scan, φ scan, and pole figure. The observed low-field butterfly-shaped magnetoresistance (MR) are explained by the primary fast rotation of the spins far away from antiphase boundaries and the high-field MR changing linearly with magnetic field can be understood by the gradual rotation of the spins near the antiphase boundaries. It is magnetocrystalline anisotropy that causes an increase in MR below Verwey transition temperature.