Magnetoelectric properties of magnetite thin films

Abstract

Resistivity, DC Hall effect and transverse magnetoresistance measurements were made on polycrystalline thin films of magnetite (Fe₃O₄) from 104K to room temperature. The Verwey transition is observed at T_V=123K, about 4K higher than reported for bulk magnetite. The ordinary and extraordinary Hall coefficients are negative over the entire temperature range, consistent with negatively charged carriers. The extraordinary Hall coefficient exhibits a rho ^1/3 dependence on the resistivity above T_V and a rho ^2/3 dependence below T_V. The magnetoresistance is negative at all temperatures and for all magnetic field strengths. The planar Hall effect signal was below the sensitivity of the present experiment.