Spin State of Co3+in LaCo1-xRhxO3Investigated by Structural Phenomena
Abstract
Neutron diffraction for a polycrystalline sample of LaCo$_{0.8}$Rh$_{0.2}$O$_{3}$ and synchrotron x-ray diffraction for polycrystalline samples of LaCo$_{0.9}$Rh$_{0.1}$O$_{3}$ and LaCo$_{0.8}$Rh$_{0.2}$O$_{3}$ have been carried out in order to investigate the structural properties related with the spin state of Co$^{3+}$ ions. We have found that the values of the Co(Rh)-O bond lengths in the Co(Rh)O$_{6}$ octahedron of LaCo$_{0.8}$Rh$_{0.2}$O$_{3}$ are nearly identical at 10 K. The lattice volume for the Rh$^{3+}$ substituted samples decreases with the thermal expansion coefficient similar to that of LaCoO$_{3}$ from room temperature, and ceases to decrease around 70 K. These experimental results favor a mixed state consisting of the high-spin-state and low-spin-state Co$^{3+}$ ions, and suggest that the high-spin-state Co$^{3+}$ ions are thermally excited in addition to those pinned by the substituted Rh$^{3+}$ ions.
- Publication:
-
Journal of the Physical Society of Japan
- Pub Date:
- November 2013
- DOI:
- 10.7566/JPSJ.82.114606
- arXiv:
- arXiv:1309.0658
- Bibcode:
- 2013JPSJ...82k4606A
- Keywords:
-
- Condensed Matter - Strongly Correlated Electrons
- E-Print:
- 6 pages, 5 figures