ABSTRACT
Transition and rare earth metal oxides are the fundamental ingredients for the advanced smart and functional materials. Many functional properties of inorganic materials are determined by the elements with mixed valences in the structure unit [1], by which we mean that an element has two or more different valences while forming a compound. The discovery of high-temperature superconductors is a successful example of the mixed valence chemistry, and
“DK3029_C004” — #2
the colossal magnetoresistivity (CMR) [2,3] observed in the perovskite structured La1−xAxMnO3 (A = Ca, Sr, or Ba) is another example. Transition and rare earth metal elements with mixed valences are mandatory for these materials to stimulate electronic, structural, and chemical evolution leading to specific functionality.
