Magnetic and electrical anomalies in LaCoO3

The electrical conductivity and Seebeck coefficient of LaCoO3 drops rapidly with increasing temperature in the vicinity of 500°K. The magnetic moment per cobalt atom also changes by about one Bohr magneton in the same temperature range. These results have been explained by a model in which an electron is thermally excited from one 3d level to another with an accompanying change in spin, and in which the difference in energy of the two levels decreases with increasing population of the upper level because of electrostatic interaction.