PROBLEM TO BE SOLVED : To provide a thermoelectric conversion material containing a half-Heusler compound as a main phase, having high Seebeck coefficient and low resistivity, sufficiently reduced thermal conductivity, and large dimensionless performance index ZT.
SOLUTION : The material is characterized by having as a main phase with an MgAgAs type crystal structure represented by the formula (Tia1Znb1Hfc1)xNiySn100-x-y or (Lnd(Tia2Znb2Hfc2)1-d)xNiySn100-x-y, wherein 0
