Preparation and study of thermoelectric properties of fine grains Gd sub(x)Zn sub(1-x)O

• Published in: Physica status solidi. A, Applications and materials science Vol. 210; no. 12; pp. 2693 - 2698
• Main Authors: Le, Thi Ngoc Ha, Hou, Frances, Vo, Thi Thanh Xuan, Pham, Quoc Nghi, Berardan, David, Dragoe, Nita
• Format: Journal Article
• Language: English
• Published: 01.12.2013
• Subjects: Electric power generation; Electrical resistivity; Evolution; Gadolinium; Nanostructure; Pellets; Spark plasma sintering; Thermoelectricity
• ISSN: 1862-6300; 1862-6319
• DOI: 10.1002/pssa.201329140

Gd sub(x)Zn sub(1-x)O 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, Gd sub(2)O sub(3), 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 ( rho ) of about 5.910 super(-3) ( Omega cm) and a Seebeck coefficient (S) of -164 mu VK super(-1), corresponding to a power factor (S super(2)/ rho ) of 0.46mWK super(-2)m super(-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.