The evolution of the electronic, structural, magnetic (macroscopic and elementspecific) properties of LaFe12B6 across the field-induced firs

In the proposed experiment, we want to study a first-order phase transition (FOT) near 50 K from the antiferro-(AF) to ferromagnetic (FM) state in LaFe12B6. The FOT implies a strong interrelation between the crystal structure and the magnetic sublattice of the sample, but its mechanism is yet to be fully understood. Recently, we have developed a unique setup at ID12 of ESRF to measure simultaneously macroscopic properties (magnetization, magnetostriction, magnetocalorics, resistivity…) and element specific atomistic properties (XAS/XMCD). Using such device to investigate LaFe12B6, we will be able to correlate the FOT in atomistic and macroscopic approach. In addition, XMCD will probe the magnetic moment on La during the FOT, which is expected to be non-null based on recent experiments performed on LaFe13Si measurement. These results will help understanding the FOT based on a material with potential cooling application like magnetocaloric hydrogen liquefaction.