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On the Verwey Transition in Magnetite

1972; Wiley; Volume: 54; Issue: 2 Linguagem: Inglês

10.1002/pssb.2220540210

1521-3951

B. Lorenz, D. Ihle,

Magnetic Properties and Applications

Abstract The Verwey transition in magnetite is investigated using a band model with interatomic Coulomb energy introduced by Cullen and Callen. This model is treated in the Hartree‐Fock approximation. A tight‐binding calculation of the band structure with Verwey ordering yields a gap in the single‐particle excitation spectrum for M = ( U /2|h|) m > 1 ( U Coulomb energy, h overlap integral, m ordering parameter). Below the Verwey temperature T v semiconducting behaviour for M > 1 and a region of gapless Verwey ordering and semimetallic behaviour for 0 < M ⩽ 1 is found.