2Co 9O 14]]>

摘要

The insulator-insulator transition, at Tt?=?570?K, in layered cobalt oxide Ba2Co9O14was investigated using Raman scattering technique. High temperature (300–800?K) measurements have evidenced no structural transition occurring at Tt. The obtained results are rather consistent with low to high spin-state transition of Co3+ions in the Co3O12octahedral trimer. More precisely, only one cobalt ion located in the central octahedron of the trimer undergoes this transition.