Electronic Anisotropy and Magnetic Structure of Iridates Studied by NRS

DESY Photon Science User Meeting 2017, Hamburg, Germany, 27 Jan 2017 - 27 Jan 2017
We report on the first observation of nuclear forward scattering (NFS) of synchrotron radiation at the 73 keV $^{193}$-Ir resonance at PETRA III. The large penetration depth of 73 keV photons, the high natural abundance of $^{193}$-Ir (63%), and polarisation dependence of NFS provide unique possibilities to study the electronic and magnetic properties of 5d-transition metal oxides. Standard sample preparation is applicable and no isotopic enrichment is necessary. The hyperfine interactions in Ir metal, IrO$_2$, and in Sr$_2$IrO$_4$ have been studied by NFS. Electric field gradients and magnetic hyperfine fields in Sr$_2$IrO$_4$ have been determined in zero field and in a small, 0.53(5) T external magnetic field. The NFS experiment on Ir metal is possible even at room temperature.