Copper ferrite revisited

摘要: Abstract Reinvestigation of the Jahn-Teller distortion copper ferrospinel has established that critical number octahedral-site Cu 2+ ions per formula unit for a cooperative to tetragonal symmetry at room temperature is ca 0.8. Several anomalies associated with tetragonal-cubic transition have been noted in literature; these are shown reflect not only tendency segregation into Cu-rich and Cu-poor regions neighborhood T t , but also quenching both tetrahedral-site oxygen vacancies on rapid cooling. The intersite exchange A + Fe 3+ B = reestablish equilibrium becomes facile near 250°C; reoxidation 325°C. This resolution two processes quenched samples reflected variation c ratio electrical resistance below ; variations can be interpreted terms concentration splitting energies.