John B. Goodenough - Fundamental Investigations Throughout His Career

Fundamental Investigations Throughout His Career

On the fundamental side, his research has focused on magnetism (e.g. the Goodenough-Kanamori rules) and on the transition from magnetic-insulator to metallic behavior in transition-metal oxides. On the basis of the Virial Theorem, he recognized that this transition should be first-order and should, where the phase transition occurs at too low a temperature for atomic diffusion, result in lattice instabilities. At this crossover, these instabilities lead to charge-density waves in single-valent oxides and to phase-fluctuations in mixed-valent oxides. The phase fluctuations are responsible for such unusual physical properties as high-temperature superconductivity in copper oxides and a colossal magnetoresistance in manganese and cobalt oxides.