Open AccessSynthesis and electrical properties of dual doped CaMnO3 based ceramics
Author(s) -
Hongchao Wang,
Chunlei Wang,
Wenbin Su,
Jian Liu,
Yuhan Sun,
Peng Hua,
Jialiang Zhang,
Zhao Ming-Lei,
Jichao Li,
Ning Yin,
Mei Liang-Mo
Publication year - 2011
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.60.087203
Subject(s) - seebeck coefficient , materials science , electrical resistivity and conductivity , temperature coefficient , atmospheric temperature range , condensed matter physics , dopant , curie temperature , doping , orthorhombic crystal system , scanning electron microscope , analytical chemistry (journal) , crystal structure , composite material , thermal conductivity , thermodynamics , crystallography , optoelectronics , chemistry , physics , electrical engineering , chromatography , ferromagnetism , engineering
Different Nb doped Ca0.9Yb0.1Mn1-xNbxO3 ceramics are successfully synthesized by the conventional solid state reaction technique. The crystal structures are of orthorhombic phase, belonging to the Pnma space group. The lattice constant and the volume increase with the increase of Nb content. Relatively high density is around 97%. Scanning electron microscope (SEM) images show that samples are well crystallized. The electrical resistivity and the Seebeck coefficient are measured in a temperature range between 300 and 1100 K. At low temperatures, the electrical resistivity shows a semiconductive-like behavior. At high temperatures, the electrical resistivity exhibits a typical metallic conductive behavior. The semiconductor-metal transition temperature shifts toward a higher temperature with the increase of Nb content. The electrical resistivity increases with Nb dopant, except that the electrical resistivity for x=0.03 is slight lower than that fox x=0.00 sample at high temperature range. This conductivity behavior can be understood as the fact that though Nb doping can introduce more carriers, it also distorts the MnO6 octahedra, and causes the carrier localization. The values of Seebeck coefficient are all negative, indicative of an n-type electrical conduction. The absolute value of Seebeck coefficient increases with temperature increasing, but decreases with the increase of Nb content. The highest power factor is obtained to be 297 W/K2m at 497 K in the x=0.00 sample, and the power factor of this sample is less independent of temperature in the whole measured temperature range.