Extremely low coercivity in Fe3O4 thin film grown on Mg2TiO4 (001)

Abstract

We report very different magnetic properties of 40 nm-thick Fe₃O₄ thin films grown on tailored spinel substrate Mg₂TiO₄ (001) and on general substrate MgO (001). The sample on Mg₂TiO₄ (001) shows a very sharp Verwey transition with narrow hysteresis of only 0.5 K and a high transition temperature up to 126 K and, in particular, an extremely small coercivity as low as around 7 Oe from the Verwey transition to room temperature. This low coercivity is close to that of the single crystal bulk but several times smaller than that of the sample on MgO (001). Our work gives a first example of the magnetic properties in Fe₃O₄ thin film having higher Verwey transition than that of the single crystal bulk, which not only greatly expands our understanding about Fe₃O₄ but also provides a very good candidate for spintronic applications with quite low energy consumption.