X-ray detected magnetic resonance at the Fe K-edge in YIG: forced precession of magnetically polarized orbital components

X-ray Detected Magnetic Resonance (XDMR) has been measured for the first time on exciting the Fe K-edge in a high quality Yttrium Iron Garnet film epitaxially grown on a Gadolinium Callium Garnet substrate. This challenging experiment required resonant pumping of Yttrium Iron Garnet at high microwave power, i.e. in the foldover regime. X-ray Magnetic Circular Dichroism (XMCD) was used to probe the change in the longitudinal component of the magnetization $M_{Z}$ induced by the precession of magnetic moments located at the iron sites. Since XMCD at the Fe K-edge refers mostly to the equilibrium contribution of magnetically polarized $4p$ orbital components, XDMR at the Fe K-edge should reflect the precessional dynamics of the latter orbital moments. From the measured precession angle, we show that there is no dynamical quenching of the polarized orbital components at the iron sites in Yttrium Iron Garnet.