Transition metal oxide films

The sol‐gel method can be used to produce multicomponent oxide materials which have a homogeneous composition even at the atomic level. Thin transition metal oxide films are shown to exhibit different properties from those of the bulk materials and both the crystal structure and the valence state of the materials can be sensitively controlled by doping. Recent progress in the field is reviewed, including the production of highly oriented films, valence‐controlled oxides, the control of instable phase formation and atmosphere‐sensitive structural transformations.