Spin states and phase separation in La_{1-x}Sr_{x}CoO_3 (x=0.15, 0.25, 0.35) films: optical, magneto-optical and magneto-transport studies

Abstract

Optical absorption and transverse Kerr effect spectra, resistivity and magnetoresistance of La${}_{1-x}$Sr${}_x$CoO${}_3$ ($x=0.15,0.25,0.35$) films have been studied. The temperature dependencies of the optical and magneto-optical properties of the films exhibit features, which can be attributed to the transition of the Co${}^{3+}$ ions from the low-spin state (S=0) to the intermediate-spin state (S=1) and to orbital ordering of the Co${}^{3+}$ ions in the latter state. The evolution of the properties influenced by doping with Sr is interpreted on the basis of the phase separation model.

22 pages, 10 figures, submitted to Rhys. Rev. B