We have investigated the structural, electronic, and magnetic properties of the pyrochlore iridates Eu2Ir2O7 and Pr2Ir2O7 using a combination of resonant elastic x-ray scattering, x-ray powder diffraction, and resonant inelastic x-ray scattering (RIXS). The structural parameters of Eu2Ir2O7 have been examined as a function of temperature and applied pressure, with a particular emphasis on regions of the phase diagram where electronic and magnetic phase transitions have been reported. We find no evidence of crystal symmetry change over the range of temperatures (~6 to 300 K) and pressures (~0.1 to 17 GPa) studied. We have also investigated the electronic and magnetic excitations in single crystal samples of Eu2Ir2O7 and Pr2Ir2O7 using high resolution Ir L3-edge RIXS. In spite of very different ground state properties, we find these materials exhibit qualitatively similar excitation spectra, with crystal field excitations at ~3-5 eV, spin-orbit excitations at ~0.5-1 eV, and broad low-lying excitations below ~0.15 eV. In Eu2Ir2O7 we observe highly damped magnetic excitations at ~45 meV, which display significant momentum dependence. We compare these results with recent dynamical structure factor calculations.
@article{arxiv.1510.07934,
title = {X-ray scattering study of pyrochlore iridates: crystal structure, electronic and magnetic excitations},
author = {J. P. Clancy and H. Gretarsson and E. K. H. Lee and Di Tian and J. Kim and M. H. Upton and D. Casa and T. Gog and Z. Islam and Byung-Gu Jeon and Kee Hoon Kim and S. Desgreniers and Yong Baek Kim and S. J. Julian and Young-June Kim},
journal= {arXiv preprint arXiv:1510.07934},
year = {2016}
}