ELECTRICAL TRANSPORT IN MAGNETITE NEAR THE VERWEY TRANSITION

Thermoelectric power and conductivity measurements were carried out on Ti-doped single crystals of magnetite in the temperature range 70-300 K. The analysis of the measurements supports the model in which the electrical conduction below the Verwey transition takes place on two energy levels separated by a gap of about 0.12 eV. Evidence is found that the mobility of the electrons is thermally activated above as well as below the Verwey transition, indicating phonon-assisted tunneling. © 1979 The American Physical Society.