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Thermoelectric Efficiency of Reduced SrTiO 3 Ceramics Modified with La and Nb
Author(s) -
Teranishi Takashi,
Ishikawa Yusuke,
Hayashi Hidetaka,
Kishimoto Akira,
Katayama Misaki,
Inada Yasuhiro
Publication year - 2013
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.12379
Subject(s) - materials science , sintering , analytical chemistry (journal) , ceramic , seebeck coefficient , electrical resistivity and conductivity , strontium titanate , mineralogy , thermoelectric effect , doping , metallurgy , chemistry , nanotechnology , composite material , thermal conductivity , thin film , physics , optoelectronics , chromatography , thermodynamics , quantum mechanics
Ceramics of La x Sr 1− x Nb y Ti 1− y O 3 ( LSNT ) were synthesized under various reducing atmospheres. Covering the specimens with graphite carbon felt under an Ar‐gas flow during sintering drastically enhanced the electrical conductivity, σ. Ti K‐edge absorption spectra indicated the presence of Ti 3+ for heavily reduced specimens. The increase in conductivity was attributed to the 3d band of Ti 3+ . The maximum value for the figure of merit, ZT , was obtained for strontium titanate ceramics modified with both 5 mol% La and 5 mol% Nb, namely 5/5‐LSNT, exhibiting a ZT value of ~0.221 at 473 K. This high ZT value was almost 1.5 × larger than that of the conventional 10 mol% La‐doped sample, 10/0‐LSNT ( ZT ~0.144), and was mainly attributed to the larger Seebeck coefficient of the material.