Remarkable thermal hysteresis of thermal conductivity in nearly freestanding VO2 nanowire across the phase transition

Abstract

The thermal conductivity of a nearly freestanding VO2 nanowire was measured in the vicinity of phase transition temperature using thermal bridge method. It was discovered that the thermal conductivity measured during cooling can be significantly greater than during heating in the temperature range of 315–355 K. The pronounced hysteresis results from a large phase transition temperature range during cooling as confirmed by optical imaging and Raman studies. However, this behavior was absent in clamped VO2 nanowires, suggesting that even small thermal stress can change the thermal behavior of VO2 nanowires during phase transition.