Rao C N R, Vanitha P V, Cheetham Anthony K
CSIR Centre of Excellence in Chemistry, Jawaharlal Nehru Center for Advanced Scientific Research, Jakkur P.O., Bangalore 560 064, India.
Chemistry. 2003 Feb 17;9(4):828-36. doi: 10.1002/chem.200390092.
A fascinating phenomenon, recently found to occur in certain transition-metal oxides, is phase separation wherein pure, nominally monophasic oxides of transition metals with well-defined compositions separate into two or more phases over a specific temperature range. Such phase separation is entirely reversible, and is generally the result of a competition between charge-localization and -delocalization, the two situations being associated with contrasting electronic and magnetic properties. Coexistence of more than one phase, therefore, gives rise to electronic inhomogeneity and a diverse variety of magnetic, transport, and other properties, not normally expected of the nominal monophasic composition. An interesting feature of phase separation is that it covers a wide range of length scales anywhere between 1-200 nm. While cuprates and manganates, especially the latter, provide excellent examples of phase separation, it is possible that many other transition-metal compounds with extended structures will be found to exhibit phase separation.
