Thermoelectric properties of p-type half-Heusler compound: Sn-doped ErNiSb

Polycrystalline half-Heusler compounds of Sn doped ErNiSb ldquoErNiSn_xSb_1-x (x = 0.00 and 0.05)rdquo were prepared by a spark plasma sintering (SPS) technique. Their thermoelectric properties were evaluated in the temperature range from room temperature to around 1000 K. For ErNiSb, the Seebeck coefficient S indicated positive, and approached 280 muV K^-1 around 400 K. The values of the electrical resistivity rho were on the order of 10^-5 Omega m. The S and rho indicated semiconductor like characteristic at high temperatures. The maximum value of the power factor S² rho^-1 was 1.4times10^-3 W m^-1 K^-2 around 400~600 K. For 5% Sn-doped ErNiSb: ErNiSn_0.05Sb_0.95, both the rho and S were lower than those of ErNiSb. Hall effect measurement revealed that Sn-doping led to increase the carrier concentration of ErNiSb. Sn-doping improved the S² rho^-1 of ErNiSb. The S² rho^-1 reached 1.8times10^-3 W m^-1 K^-2 around 650 K.