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Preparation and study of thermoelectric properties of fine grains Gd x Z n 1− x O
Author(s) -
Le Thi Ngoc Ha,
Hou Frances,
Vo Thi Thanh Xuan,
Pham Quoc Nghi,
Berardan David,
Dragoe Nita
Publication year - 2013
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.201329140
Subject(s) - spark plasma sintering , seebeck coefficient , materials science , electrical resistivity and conductivity , thermoelectric effect , analytical chemistry (journal) , sintering , thermoelectric materials , pellets , grain size , hall effect , phase (matter) , mineralogy , metallurgy , thermal conductivity , composite material , chemistry , thermodynamics , electrical engineering , chromatography , physics , engineering , organic chemistry
Gd x Zn 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 25 nm 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 2 O 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 ( ρ ) of about 5.9 × 10 −3 (Ω cm) and a Seebeck coefficient ( S ) of −164 µV K −1 , corresponding to a power factor ( S 2 / ρ ) of 0.46 mW K −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.