Optimization of Mg_2Si by doping the rare earth elements

The rare earth elements(Sc,Y) doped Mg2Si based thermoelectric materials were prepared by field-activated and pressure-assisted synthesis(FAPAS).The samples by this method own uniform and compact structure,the average grain size was about 1.5-2μm,micro-content of rare earth element did not change the morphology of matrix.The two dopants enhanced the thermoelectric properties at varying degrees,the power factor of samples doped with 0.427mol%Sc and 0.173mol%Y were 2.67 times and 2.03 times of that of non-doped Mg2Si at 378 and 468K respectively,and the thermal conductivity of the latter reduced by 20%.Thus,the figure of merit ZT of 0.173mol%Y doping sample reaches to 1.30 times of the pure Mg2Si,its ZTmax-0.23,obviously higher than 0.18 belonging to the latter.