Measurement and Modeling of the Thermal Properties' Hysteresis of VO2 Films
Aula: Sala Riunioni - Ore: 9.30-12 e 14-16.30
Via Musei 41, Brescia
Centre National de la Recherche Scientique (CNRS)
Hysteresis loops exhibited by the thermal properties of VO2 thin films are experimentally measured and theoretically modeled. This is achieved by directly measuring through photothermal radiometry the thermal diffusivity and thermal effusivity of the VO2 samples during their heating and cooling processes across their phase transitions. These thermal properties are then used to determine the thermal conductivity and volumetric heat capacity of the VO2 samples. A significant enhancement of the VO2 thermal conductivity is observed during the heating process, while its volumetric heat capacity exhibits a sharp peak at the middle of the phase transition. The temperature variations of these two latter properties are accurately described by means of an explicit expression derived for the temperature evolution of the volume fractions of the metallic and isolating domains appearing during the heating and cooling of VO2, respectively.