ANALYSIS OF THE VERWEY TRANSITION IN MAGNETITE

A review is presented of work carried out in the author's laboratory concerning the thermodynamic and electrical transport phenomena in magnetite. The need for careful compositional control of single crystal growth is emphasized. With increasing deviations from the ideal Fe3O4 composition the Verwey transition suddenly shifts from the first order to a higher order regime. This hitherto unrecognized feature is documented by a variety of experimental techniques and is rationalized in terms of a single formalism based on a mean field theoretic approach. The agreement between theory and experiment is very good. Various aspects of the theoretical analysis are discussed in detail; the formalism is of much more general appreciability than the Limited use to which it was put in the resolution of the Verwey problem.