Thermal diffusivity measurements using dual probe Scanning Thermal Microscopy

We present a novel dual probe Scanning Thermal Microscopy setup and methodology for addressing measurements of thermal diffusivity using two microscale thermal probes placed at mutual distance between 1 to $60\mu m$, monitoring propagation of heat pulses from one probe to another one through the studied sample. It is shown that even if the measured heat pulses are very weak in this configuration, they can be measured if the heat transfer via air is reduced by measuring in vacuum, radiative heat transfer is reduced by suitable measurement protocol and many pulses are averaged. Resulting signals show the expected dependencies and thermal diffusivity can be evaluated from them with a help of a numerical modeling. Diffusivity measurements are demonstrated on glasses and polymer samples and potential uncertainty sources are identified.