Introduction.

Transition-metal oxides form a fascinating class of compounds with a wide range of technological applications. They are used in catalysis, lasers, and magnetic recording tapes, as well as in sensors for very high pressures and for gases, for example. New applications in magnetic-field sensors, based on the principle of giant magnetoresistance [67], and in transparent transistors, applicable as on-screen electronic devices in displays or cameras [165], were added recently. In addition, they are responsible for the occurrence of high-temperature superconductivity. [ABSTRACT FROM AUTHOR]