Bridging the gap between atomistic and macroscopic descriptions of 1st -order magnetic transitions by simultaneous micrometric XMCD imaging

First-order magnetic transitions involve structural, magnetic and electronic changes that are relatively well described at the scale of a unit cell. They have established spectacular consequences on bulk physical properties such as magnetization, transport or thermal properties, which form the basis of their applications. However, the intermediate micrometric length scale remains widely unexplored and poorly described. We seek to understand how a field induced para- to ferro-magnetic first-order transition develop locally in comparison to the overall macroscopic response in physical properties. Taking advantage of the XMCD magnetic contrast and the possibility to focus the beam to a micrometric size, we will perform simultaneous XMCD imaging and bulk physical measurements on one MnFe(P,Si) single-crystal and one polycrystalline sample.