Metallization of magnetite at high pressures

We report on the first finding that an insulator to metal transition (i.e. Verwey transition) of magnetite (Fe3O4) lakes place at absolute zero temperature as a function of pressure. In order to investigate the Verwey transition, we measured the electrical resistivity on two single crystalline samples with distinct oxygen compositions of Fe3O4.002 and Fe3O4.007 at temperatures from 300K down to 3 K under a pressure up to 9 GPa using a cubic anvil apparatus. The Verwey transition temperature of these samples suddenly disappears at a certain critical pressure P-c in between 6 and 8 GPa. We confirmed that a metallic ground state is realized in magnetite under pressure above P-c. (C) 2002 Elsevier Science B.V. All rights reserved.