Abstract
The interplay between spin-orbit coupling (SOC) and electron correlation () is considered for many exotic phenomena in iridium oxides. We have investigated the evolution of structural, magnetic, and electronic properties in the pyrochlore iridate where the substitution of Ru has been aimed to tune this interplay. The Ru substitution does not introduce any structural phase transition, however, we do observe an evolution of lattice parameters with the doping level . X-ray photoemission spectroscopy (XPS) study indicates Ru adopts the charge state of and replaces the accordingly. Magnetization data reveal both the onset of magnetic irreversibility and the magnetic moment decreases with progressive substitution of Ru. These materials show a nonequilibrium low temperature magnetic state as revealed by magnetic relaxation data. Interestingly, we find the magnetic relaxation rate increases with substitution of Ru. The electrical resistivity shows an insulating behavior in the whole temperature range, however, resistivity decreases with the substitution of Ru. The nature of electronic conduction has been found to follow power-law behavior for all the materials.
1 More- Received 18 November 2016
- Revised 18 January 2017
DOI:https://doi.org/10.1103/PhysRevB.95.054415
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