Study on Transport Property of VO2 thin Film Observed by Temperature and Magnetic Field Dependence of Hall Effect and Temperature Dependence of Seebeck Effect

Abstract

Here, we investigated the temperature and magnetic-field-dependent Hall effect and temperature-dependent Seebeck effect in VO₂ thin films by using physical property measurement systems. It was observed from the ordinary Hall effect measurement from room temperature to 370K that the Hall voltage decreased with increasing external magnetic field and dominant carriers changed near the critical temperature where an insulator-to-metal transition in VO₂ was triggered. The decrease of the Hall voltage implies the weakening of the strong electron correlation with increasing applied magnetic field. In the case of the Seebeck coefficient in VO₂ thin films, its negative slope variation was obtained with respect to the temperature gradient between two ends of the VO₂ film at room temperature. The Seebeck coefficient could be evaluated as -250 and -28㎶/K at 300 and 360K, respectively. Near the critical temperature of VO₂, the rate of change in the Seebeck coefficient with respect to the temperature gradient showed a gradual decrease in its magnitude and then changed its sign with increasing temperature gradient. This peculiar variation of the rate of change in the Seebeck coefficient in the vicinity of the critical temperature seems to stem from the percolated motion of the structural phase transition in VO₂.