Magnetic force microscopy of epitaxial magnetite films through the Verwey transition

摘要

Magnetic force microscopy was performed on 300 nm thick magnetite films grown epitaxially on MgO (001) at temperatures ranging from well below to well above the Verwey transition temperature, T_v. Frequency shift images were acquired at different locations on the sample as temperature was increased through the Verwey transition. The magnetic domain features are persistent at all temperatures, which indicates that the domains are pinned across the phase transition, probably due to antiphase boundaries. An enhancement of magnetic contrast below T_v indicates the moments tilt out of the plane below T_v, which is corroborated by superconducting quantum interference device magnetometry.