Unconventional magnetism in a layered rhodium oxide
The spin degree of freedom in transition-metal oxides is of importance for understanding the magnetism as well as for clarifying various interesting electronic properties such as high-Tc superconductivity in cuprates and large thermoelectric coefficient in cobalt oxides. In spite of rich experimental and theoretical investigations for such functional properties in 3d-electron systems, the 4d-electron oxides have been less studied and there are a number of puzzling issues for the spin state. Here we focus on the spin state of Rh ions in the layered rhodium oxide LaSrRhO4. In sharp contrast to a collective wisdom that a trivalent Rh ion is nonmagnetic, we find that a few percent of Rh ions show a paramagnetic behavior with S=1 in the present system. It is also revealed that the fraction of the magnetic Rh ions depends on the degree of disorder, suggesting one possible origin for understanding various magnetic states emerged in transition-metal oxides.
"Unconventional magnetism in the layered oxide LaSrRhO4"
by N. Furuta, S. Asai, T. Igarashi, R. Okazaki, Y. Yasui, I. Terasaki, M. Ikeda, T. Fujita, M. Hagiwara, K. Kobayashi, R. Kumai, H. Nakao, and Y. Murakami
Phys. Rev. B 90, 144402 (2014).
(Figure) Magnetization curves in LaSrRhO4.