Verwey transition

The Verwey transition refers to a low-temperature phase transition in the mineral magnetite at around 125 K and the attendant changes in its magnetic, electrical, and thermal properties. Upon warming through the Verwey transition temperature (TV), the magnetite crystal lattice changes from a monoclinic structure to the cubic inverse spinel structure that persists at room temperature.[1] The phenomenon is named after Evert Verwey, a Dutch chemist who first recognized the connection between the structural transition and the changes in the physical properties of magnetite.

The Verwey transition is associated with, but distinct from, a magnetic isotropic point in magnetite, at which the first magnetocrystalline anisotropy constant changes sign from positive to negative. The temperature and physical expression of the Verwey transition are highly sensitive to the stress state of magnetite and the stoichiometry. Non-stoichiometry in the form of metal cation-substitution or partial oxidation can lower the transition temperature or suppress it entirely.[2]

References

  1. ↑ Gubbins, D., & Herrero-Bervera, E. (Eds.). (2007). Encyclopedia of geomagnetism and paleomagnetism. Springer Science & Business Media.
  2. ↑ Aragón, R., Buttrey, D. J., Shepherd, J. P., & Honig, J. M. (1985). Influence of nonstoichiometry on the Verwey transition. Physical Review B, 31(1), 430.
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