Simple interpretation of the Verwey transition in magnetite

Journal Article · Thu Nov 01 04:00:00 EST 1990 · Journal of the American Ceramic Society; (United States)

DOI:https://doi.org/10.1111/j.1151-2916.1990.tb06442.x· OSTI ID:5155161

Honig, J M; Spalek, J; Gopalan, P ^[1]

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1. Dept. of Chemistry, Dept. of Physics, Purdue Univ., West Lafayette, IN (US)

The Verwey transition in magnetite is rationalized in terms of an electronic model involving correlated electron occupancy of nearest-neighbor octahedral site pairs. This formalism can be restated in terms of order- disorder theory. The site pair representation of the lattice is analyzed in terms of possible occupation states that represent respectively the ground state of the system as a trapped electron, a first excited state in which an electron can resonate between the two constituents of a site pair, and a second excited state involving two electrons on neighboring sites. The free energy of this representative assembly is then minimized to obtain the equilibrium configuration. The Verwey transition is driven by the Coulomb repulsive interaction between electrons on neighboring sites. In certain limiting cases one obtains results equivalent to the phenomenological Strassler-Kittel model, which had been successfully used on an empirical basis to analyze both the first- and second-order Verwey transitions that have been experimentally encountered with increasing departures from the ideal 4/3 ratio of oxygen/iron in magnetite.

• OSTI ID: 5155161
• Journal Information: Journal of the American Ceramic Society; (United States), Journal Name: Journal of the American Ceramic Society; (United States) Vol. 73:11; ISSN JACTA; ISSN 0002-7820
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
COULOMB FIELD
ELECTRIC FIELDS
ELECTRONS
ELEMENTARY PARTICLES
ELEMENTS
ENERGY LEVELS
EQUILIBRIUM
EXCITED STATES
FERMIONS
GROUND STATES
IRON
IRON ORES
LEPTONS
MAGNETITE
METALS
MINERALS
NONMETALS
ORES
OXIDE MINERALS
OXYGEN
PHYSICAL PROPERTIES
THERMODYNAMICS
TRANSITION ELEMENTS