Multiferroic Coupling in Magnetite Single Crystal

Magnetisation measurements from a single crystal of magnetite show unusual behaviour immediately below the Verwey transition with hysteresis loops showing anomalous hysteretic behaviour around ±0.5 T and between 80 K and 130 K. Magnetic Force Microscopy (MFM) data show different magnetic switching behaviours across this same temperature and field range as compared to that observed either above 125 K or below 80 K. The observed magnetic behaviour is therefore linked with the structural changes that occur at the Verwey transition and this is thought to arise through a magneto-elastic coupling between the ferrimagnetic domains and ferroelastic twins created at the Verwey transition. There is, unfortunately, very little experimental data exploring the structure-magnetic correlation and its evolution as a function of applied field and the effect this has on the ferroelastic twins. We therefore propose a structural characterisation using X-Ray Diffraction (XRD) as a function of field and temperature across the Verwey transition to provide new insights into the complex interplay between the ferroic orders in the vicinity of the metal-insulator Verwey transition.