[9p-W933-1~11] New trend of multinary compound research ~ control of physical properties, new application~

[9p-W933-3] Development of novel magnetic semiconductor thermoelectric materials and devices

〇Takao Mori^1,2 (1.NIMS, 2.Univ. Tsukuba)

Keywords:thermoelectric material, magnetic semiconductor

New principles and strategies are desired to overcome the traditional tradeoff between thermoelectric (TE) properties, i.e. electrical and thermal conductivity, and Seebeck coefficients. We have been trying to develop TE enhancement principles which can be relatively easily implemented and applied widely. Introducing a moderate volume of nano-micropores with size distribution by simple evaporation of a secondary phase, has led to effective phonon selective scattering, and 100% enhancement to figure of merit ZT~1.6 in rare earth-free (“empty”) skutterudites. We have also proposed to utilize magnetic interactions between carriers and magnetic moments to enhance the power factor. Unlike magnon drag, TE enhancement via magnetic interaction is not solely dependent on ordering, and is effective at higher temperatures also. Magnetic ion doping for example, has led to TE enhancement, if effective coupling is created. We have also demonstrated significant enhancement of the Seebeck coefficient and power factor via spin fluctuation.