Ordering and self-diffusion in FePt alloy film

Abstract

Neutrons have different scattering cross-sections for the isotopes of an element. Also, they interact with the un-paired electrons in a magnetic sample due to their magnetic moment. Neutron reflectivity or reflectometry is a technique which measures the depth profile of a sample. Using polarized neutrons, both self-diffusion and magnetism can be probed in a unique way. In the present work, polarized neutron reflectometry measurements were performed in [FePt/57FePt] multilayers across the structural ordering temperature of this sample. It was found that the structural ordering in this system is concurrent with a sudden increase in Fe diffusivity and a sudden drop in the value of the magnetic moment.