Thermoelectric properties of single crystalline B4C prepared by a floatingzone method

High-purity single crystalline B4C, several cm in size, has been prepared b y a Floating Zone method. The electrical conductivity, Hall mobility, Seebe ck coefficient and thermal conductivity are measured from room temperature to 1023 K. The electrical conductivity is about four times higher than that of sintered B4C. The mobility has increased with increasing temperature, i ndicating hopping conduction of charge carriers. The Seebeck coefficient is 240-260 mu VK-1, almost independent of temperature. The thermal conductivi ty is about twice higher than that of sintered B4C. The thermoelectric figu re-of-merit is also higher than that of sintered B4C, being 4.2 x 10(-5) K- 1 at 1100 K.