Abstract
We have performed x-ray absorption spectroscopy (XAS) measurements on a series of Ir-based 5 transition metal compounds, including Ir, IrCl, IrO, NaIrO, SrIrO, and YIrO. By comparing the intensity of the “white-line” features observed at the Ir L and L absorption edges, it is possible to extract valuable information about the strength of the spin-orbit coupling in these systems. We observe remarkably large, nonstatistical branching ratios in all Ir compounds studied, with little or no dependence on chemical composition, crystal structure, or electronic state. This result confirms the presence of strong spin-orbit coupling effects in novel iridates such as SrIrO, NaIrO, and YIrO, and suggests that even simple Ir-based compounds such as IrO and IrCl may warrant further study. In contrast, XAS measurements on Re-based 5 compounds, such as Re, ReO, ReO, and BaFeReO, reveal statistical branching ratios indicative of negligible spin-orbit coupling effects.
- Received 30 May 2012
DOI:https://doi.org/10.1103/PhysRevB.86.195131
©2012 American Physical Society