Magnetism and magnetotransport in symmetry matched spinels: Fe ₃O₄/MgAl₂O₄

In this work, we show that Fe₃O₄ films grown by oxygen plasma assisted molecular beam epitaxy have anomalous magnetic properties such as negative magnetoresistance and high saturation magnetic fields. The film substrate mismatch of 3 is relieved by the formation of misfit dislocations at the interface. Transmission electron microscopy results show that misfit dislocations are not the cause of antiphase domain boundary (APB). This suggests that in this system APB formation is a property of the three dimensional Fe₃O₄ growth.