n-p Type variation in thermoelectric AlMgB14–based materials by raw material mixture ratio

Abstract We controlled the sign of Seebeck coefficient of AlMgB 14 -based thermoelectric materials by changing the raw material ratio for spark plasma sintering. The raw material powders of Al, Mg and B were mixed by V-shape mixer then sintered at 1773 K. Some sintered samples exhibited negative Seebeck coefficients and the others did positive as established for stoichiometric AlMgB 14 . The temperature dependence of electrical conductivity was different from each other type. Rietveld refinement for XRD results about the samples revealed that Mg site in the AlMgB 14 -lattice was occupied more for negative materials than the p-type ones and the negative samples had more valence electron than the other.