Magnetite: Raman study of the high-pressure and low-temperature effects

We report the results of a low-temperature (300 K-15 K) high-pressure (up to 22 GPa) Raman study of the Verwey transition in magnetite (Fe3O4). We use additional Raman modes observed below the Verwey transition to determine how the transition temperature changes with the quasihydrostatic pressure. Increase of the pressure results in the linear decrease of the Verwey transition temperature, with no discontinuity. The corresponding pressure coefficient dT(v)/dP is found to be -5.16 +/- 1.19 K/GPa. Such a decrease is substantially larger than the one predicted by the mean-field Coulomb interaction model of the transition. (c) 2005 American Institute of Physics.