Preparation and study of thermoelectric properties of fine grains GdxZn1−xO

GdxZn1-xO nanosize powders (nominal x=0-0.03) were prepared by using a modified-Pechini method. We observed a clear diminution of the grain-size with an increase in the gadolinium nominal concentration (down to 25nm for x=0.003). Attempts to substitute larger Gd amount (x=0.05) on the Zn site were unsuccessful. The powders were densified into dense pellets using spark plasma sintering (SPS). A second phase, Gd2O3, was evidenced after the SPS step for Gd fractions as low as x=0.008. We studied the temperature-dependent thermoelectric properties and the best properties at room temperature were observed for x=0.002-0.003, with an electrical resistivity () of about 5.9x10(-3) (cm) and a Seebeck coefficient (S) of -164 mu VK-1, corresponding to a power factor (S-2/) of 0.46mWK(-2)m(-1). Hall effect measurements were carried out and the obtained results were consistent with the Seebeck coefficient and electrical resistivity evolution, in function of Gd concentration. (C) 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim