Pressure Dependence of the Verwey Temperature of Fe3-yO4Obtained by Magnetic Permeability Measurements

The magnetic permeability of stoichiometric or non-stoichiometric magnetite (Fe 3- y O 4 ) at high pressures has been measured in a piston-cylinder apparatus. The Verwey transition temperature decrease with pressure at rates of 2.7±0.1 KGPa -1 for y =0.000, 2.49±0.07 for y =0.0051, 2.3±0.1 for y =0.0063, 2.55±0.03 for y =0.0070, 2.0±0.1 for y =0.012, 2.0±0.2 for y =0.019, 2.44±0.08 for y =0.024, 2.4±0.1 for y =0.033 and 2.15±0.08 for y =0.034. A phonon-induced correlated electron transfer mechanism by Srivastava can explain the pressure dependence of the Verwey transition temperature. The temperature of the peak of temperature-permeability curve for each y decreases with increasing pressure.