ISSN:
1432-2021
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Geosciences
,
Physics
Notes:
Abstract The thermodynamic approach (mean field theory) of Strässler and Kittel has been applied to rationalize a large body of experimental work on magnetite. A single long-range order parameter suffices to describe the entropy of the Verwey transition, the Seebeck coefficient, and the resistivity of Fe3O4. The parametrization scheme yields results consistent with two regimes. For Fe3(1−δ)O4 with δ 〈δc∼0.0039 a first order Verwey transition is encountered, consistent with a nondegenerate ground and doubly degenerate excited state. For δ〉δc the transition is second-order, consistent with two doubly degenerate states. These features may be conveniently visualized by mapping the equilibrium free energy constraint into a cusp catastrophe, one of several elementary ones in Thom's classification scheme.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00311128
Permalink