XAS and XMCD studies of the low temperature magnetic and electronic properties of the Nickel Ferrite.

The Nickel Ferrite, which belongs to the inverse spinel family and presents strong similarities to the well-known Magnetite, is receiving much attention lately due to its recently observed multiferroic properties. Many questions remain concerning its structural, electronic and magnetic properties, especially at low temperature. Here we propose to perform XAS and XMCD measurements at both Fe and Ni K-edge and as function of the temperature. Our approach is to confront experimental data with FDMNES simulations, to reveal the local electronic structure and magnetic properties of each magnetic ions above and below an expected structural distortion, which could be at the origin of an ordered occupancy of the Ni2+ and Fe3+ ions, possibly responsible for the ferroelectricity recently observed at low temperature.