High-Pressure Synthesis of LuNiIrO with Ferrimagnetism and Large Coercivity.

Double-perovskite LuNiIrO was synthesized at high pressure (6 GPa) and high temperature (1300 °C). Synchrotron powder X-ray diffraction indicates that its structure is a monoclinic double perovskite (space group P2/ n) with a small, 11% Ni/Ir antisite disorder. X-ray absorption near-edge spectroscopy measurements established Ni and Ir formal oxidation states.

Local atomic geometry and Ti 1s near-edge spectra in PbTiO and SrTiO.

We study Ti 1s near-edge spectroscopy in PbTiO at various temperatures above and below its tetragonal-to-cubic phase transition, and in SrTiO at room temperature. molecular dynamics (AIMD) runs on 80-atom supercells are used to determine the average internal coordinates and their fluctuations. We determine that one vector local order parameter is the dominant contributor to changes in spectral features: the displacement of the Ti ion with respect to its axial O neighbors in each Cartesian direction, as these displacements enhance the cross section for transitions to E-derived core-hole exciton levels.