High-spin state of Co in LaCoO3 was investigated by the X-ray diffract
ion (XRD) and submillimeter ESR method. The ESR signals of high-spin s
tate Co3+ were found in the frequency range above 150 GHz at temperatu
res above 25 K. They were discussed by the thermal activation and the
crystal distortion model. The XRD and the maximum entropy method (MEM)
analysis revealed the high density of electron distribution along the
chain -O-Co-O-. (C) 1998 Elsevier Science B.V. All rights reserved.