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Electrical properties of Y/Mg modified NiO simple oxides for negative temperature coefficient thermistors
Author(s) -
He Zhenli,
Li Zhicheng,
Xiang Qinghua,
Yan Weiqin,
Zhang Hong
Publication year - 2018
Publication title -
international journal of applied ceramic technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.4
H-Index - 57
eISSN - 1744-7402
pISSN - 1546-542X
DOI - 10.1111/ijac.13084
Subject(s) - materials science , temperature coefficient , electrical resistivity and conductivity , ceramic , thermistor , non blocking i/o , grain boundary , analytical chemistry (journal) , microstructure , grain size , polaron , doping , oxide , mineralogy , composite material , metallurgy , optoelectronics , biochemistry , chemistry , physics , chromatography , quantum mechanics , electron , electrical engineering , engineering , catalysis
The semiconductors based on simple oxide have unique features with controllable electrical property by element doping. Y 3+ doped NiO (Ni 1− x Y x O, x ≤ 0.01) and Mg 2+ substituted Ni 0.995 Y 0.005 O (Ni 0.995− y Y 0.005 Mg y O, y ≤ 0.5) powders were synthesized by a wet chemical method. The related ceramics were obtained by conventional ceramic processing. Phase component, microstructure, electrical property and temperature sensitivity of the prepared ceramics were investigated. All ceramics have a rock‐salt type crystalline structure. The room‐temperature resistivity of the ceramics can be widely adjusted from 254 to 12 322 Ω·cm by changing the concentrations of Y 3+ and Mg 2+ ions. The samples show typical characteristics of negative temperature coefficient of resistivity and have high temperature sensitivity with material constants higher than 4745 K. The analysis of impedance spectra indicates that the electrical properties resulted from both grain effect and grain boundary effect. Both band conduction and small polaron hopping were proposed as possible conduction mechanisms in the studied ceramics.