Probing micro and macroscopic structural and magnetic order parameters across first-order phase transition in giant magnetocaloric Gd5(Si,Ge

In the proposed experiment we want to study two magnetic field induced transitions in the giant magnetocaloric Gd5Si2Ge2 and Gd5Si0.5Ge3.5 compounds. By leveraging from the opportunity of simultaneously measuring various atomic and macroscopic parameters at ID12 beamline we aim to perform a thorough study of how the magnetic and structural transitions are (de)coupled. In particular, Synchrotron circularly polarized x-ray beam at ID12 will allow us to probe element specific magnetism (XMCD) and correlated it to simultaneously measured macroscopic properties. Hence, we propose to measure simultaneously XMCD, Hall probe magnetization, XRD and magnetostriction with strain gages as a function of temperature, magnetic field and time. We aim to unveil the fine details of magnetostructural coupling in these materials and learn on how to tailor them towards optimal magnetocaloric energy conversion efficiency.