Thermoelectric properties of MNiSn (M=Ti,Zr,Hf) single crystals and related alloys

During the last few years a growing interest in new material classes for thermoelectric applications, such as intermetallic compounds, could be observed. Among others, the compounds MNiSn (where M=Ti,Zr,Hf) represent one of those systems and prompted us to study their properties thoroughly. In contrast to the commonly used arc melting followed by long time heat treatment, we prepared our samples by melting the elements using a Sn flux technique. The composition and structural quality was checked by different techniques, including X-ray diffraction and energy dispersive X-ray analysis EDX. We determined the thermoelectric properties over a wide temperature range and were able to evaluate the figure of merit in the range between 90 and 360 K. To reduce the thermal conductivity the possibility of alloying these ternaries was explored.