Electronic structure and local moments in single-crystaline MnFe(P,Si) probed by linear dichroic XES and HERFD-XAS

MnFe(P,Si) is one of the rare examples presenting an isostructural first-order ferromagnetic magnetic transition (FOMT) at ambient conditions. Since the discovery of their giant magnetocaloric effect, this system attracts a continuing attention, both for its potential applications and for the scientific interest to unravel the underlying physical mechanism of the FOMT. Emission spectroscopy at Fe and Mn Kβ edges, which can provide information on the local magnetic moments irrespectively of the magnetic order, is uniquely suited to address these questions. Therefore, we intend to measure the temperature dependence of Fe and Mn Kβ XES spectra across the FOMT. In addition, to clarify the change in the electronic structure we will exploit the improved resolution offered by high energy resolution fluorescence detected in XAS, as well as the directionality of XES linear dichroism to pinpoint the change in the electronic density across the FOMT to specific orbitals.