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Effects of Cation Substitution on Electrical and Thermal Transport Properties of YCrO 3 and LaCrO 3
Author(s) -
WEBER WILLIAM J.,
GRIFFIN CURTIS W.,
BATES J. LAMBERT
Publication year - 1987
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/j.1151-2916.1987.tb04979.x
Subject(s) - seebeck coefficient , polaron , electrical resistivity and conductivity , charge carrier , substituent , thermoelectric effect , materials science , analytical chemistry (journal) , thermal conductivity , activation energy , divalent , chemistry , mineralogy , stereochemistry , thermodynamics , organic chemistry , physics , metallurgy , optoelectronics , quantum mechanics , composite material , electron
High‐temperature electrical conductivity, Seebeck coefficient, and thermal conductivity measurements were used to study the effects of different cation substituents on electrical and thermal transport in YCrO 3 and LaCrO 3 . The substitution of divalent Ca and Sr for Y and La, respectively, resulted in the formation of small polarons as charge carriers. The additional substitution of Mn for Cr resulted in the formation of a second charge carrier associated with the Mn. The electrical conductivity results were consistent with thermally activated transport by hopping of a temperature‐independent carrier concentration. The activation energies were 0.20 and 0.12 eV for (Y,Ca)CrO 3 and (La,Sr)CrO 3 , respectively, and increased to about 0.50 eV with the substitution of Mn for Cr. The Seebeck coefficient increased linearly with temperature and decreased with substituent concentration for both (Y,Ca)CrO 3 and (La,Sr)CrO 3 . The substitution of Mn for Cr resulted in a Seebeck coefficient with a more complex dependence on temperature and substituent concentration. The thermal conductivity did not change significantly with either cation substitution or temperature.