Effect of Pressure on the Metal-Nonmetal Transition and Conductivity ofFe3O4

It was recently suggested that the metal-nonmetal transition which occurs in ${\mathrm{Fe}}_3$ ${\mathrm{O}}_4$ at ≃120°K may be of the Mott-Wigner type. Present results on the effects of pressure on the transition temperature and the conductivity of the low-temperature phase are consistent with such a model. ${\mathrm{Fe}}_3$ ${\mathrm{O}}_4$ may thus be the first material in which such a transition has been observed.