Nanograined n- And p-Type Chalcopyrite CuFeS2 Prepared by Mechanochemical Synthesis and Sintered by SPS

Abstract

Chalcopyrite CuFeS2, a ternary semiconductor, is an antiferromagnet with a promising thermoelectric potential. Since the thermoelectric efficiency of CuFeS2 is generally limited by high lattice thermal conductivity, it is highly desirable to lower the thermal conductivity without deterioration of other thermoelectric characteristics. Considering the interconnection between thermal conductivity, magnetic order and grain size in magnetic ceramics, we attempted to produce doped nanostructured chalcopyrite via mechanosynthesis and SPS sintering. We succeeded to prepare both n-and p-type nanostructured ceramics. We discussed the origin of highly depressed thermal conductivity with respect to the grain size and the magnetic properties, and confirm the high technological potential of high-energy milling with respect to thermoelectric potential of CuFeS2. Thermal conductivity was reduced by 35% compared to standard chalcopyrite. The maximum value of the thermoelectric figure of merit ZT was about 0.2, which is comparable to published data.