抄録
Offer Organization: Japan Society for the Promotion of Science, System Name: Grants-in-Aid for Scientific Research, Category: Grant-in-Aid for Scientific Research (C), Fund Type: -, Overall Grant Amount: - (direct: 3900000, indirect: 1170000)
The present study reveals the mechanism of the temperature-induced spin-state transition of LaCoO3 by investigating the high-field magnetization process of the doped LaCoO3 specimens. The Co3+ ions, which are in the low-spin (LS) state in the lowest temperature, are thermally excited to the high-spin (HS) state above about 30 K. However, the number of the Co3+ ions in the HS state is limited to about 15 % due to a large repulsive interaction among HS Co3+ ions. With further increase of the temperature, the remaining LS Co3+ ions are thermally excited to the intermediate-spin (IS) state around 100 K. It is suggested that other physical properties, such as magnetostriction, of LaCoO3 can be understood in accordance with the present model where HS and IS states coexist above 100 K.