Thermal characterization of micro-structured NiTi samples by 3ω scanning thermal microscopy

The lateral modifocation of the thermal conductivity of a NiTi sample have been measured by scanning thermal microscope using the 3 omega-technique. Squares of lateral length in the micrometer range had been drawn in a polycrystalline NiTi sample by a focussed ion beam of Ga. Amplitude and phase of the 3 omega-signal have been recorded at some selected positions as a function of frequency between 10Hz and 10 KHz and as a function of position at selected modulation frequencies. The 3 omega-signals are modified inside the squares as well as the border lines and also change when the temperature is increased above the martensite-austenite transition temperature.