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Thermophysical characterisation of VO 2 thin films hysteresis and its application in thermal rectification
Hysteresis loops exhibited by the thermophysical properties of VO thin films deposited on either a sapphire or silicon substrate have been experimentally measured using a high frequency photothermal radiometry technique. This is achieved by directly measuring the thermal diffusivity and thermal effu...
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Published in: | Scientific reports 2019-06, Vol.9 (1), p.8728 |
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Main Authors: | , , , , , , , , , , |
Format: | Article |
Language: | English |
Online Access: | Get full text |
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Summary: | Hysteresis loops exhibited by the thermophysical properties of VO
thin films deposited on either a sapphire or silicon substrate have been experimentally measured using a high frequency photothermal radiometry technique. This is achieved by directly measuring the thermal diffusivity and thermal effusivity of the VO
films during their heating and cooling across their phase transitions, along with the film-substrate interface thermal boundary resistance. These thermal properties are then used to determine the thermal conductivity and volumetric heat capacity of the VO
films. A 2.5 enhancement of the VO
thermal conductivity is observed during the heating process, while its volumetric heat capacity does not show major changes. This sizeable thermal conductivity variation is used to model the operation of a conductive thermal diode, which exhibits a rectification factor about 30% for small temperature differences (≈70 °C) on its terminals. The obtained results grasp thus new insights on the control of heat currents. |
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ISSN: | 2045-2322 |