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Journal of Advanced Ceramics

Authors

Haibing LI, Key Laboratory of Functional Materials and Devices for Special Environments of Chinese Academy of Sciences, Xinjiang Key Laboratory of Electronic Information Materials and Devices, Xinjiang Technical Institute of Physics & Chemistry of Chinese Academy of Sciences, Urumqi 830011, China;University of the Chinese Academy of Sciences, Beijing 100049, China;Xinjiang Research Institute of Measurement & Testing, Urumqi 830011, China
Huimin ZHANG, Key Laboratory of Functional Materials and Devices for Special Environments of Chinese Academy of Sciences, Xinjiang Key Laboratory of Electronic Information Materials and Devices, Xinjiang Technical Institute of Physics & Chemistry of Chinese Academy of Sciences, Urumqi 830011, China
Slapley THAYIL, Xinjiang Research Institute of Measurement & Testing, Urumqi 830011, China
Aimin CHANG, Key Laboratory of Functional Materials and Devices for Special Environments of Chinese Academy of Sciences, Xinjiang Key Laboratory of Electronic Information Materials and Devices, Xinjiang Technical Institute of Physics & Chemistry of Chinese Academy of Sciences, Urumqi 830011, China
Xu SANG, Key Laboratory of Functional Materials and Devices for Special Environments of Chinese Academy of Sciences, Xinjiang Key Laboratory of Electronic Information Materials and Devices, Xinjiang Technical Institute of Physics & Chemistry of Chinese Academy of Sciences, Urumqi 830011, China;University of the Chinese Academy of Sciences, Beijing 100049, China
Xiuhua MA, Key Laboratory of Functional Materials and Devices for Special Environments of Chinese Academy of Sciences, Xinjiang Key Laboratory of Electronic Information Materials and Devices, Xinjiang Technical Institute of Physics & Chemistry of Chinese Academy of Sciences, Urumqi 830011, China;University of the Chinese Academy of Sciences, Beijing 100049, China

Keywords

Sr-doped Mn-Co-Ni-O materials, negative temperature coefficient (NTC) ceramics, electrical properties, thermal shock cycling

Abstract

The Mn1.95-xCo0.21Ni0.84SrxO4 (MCNS) (0 ≤ x ≤ 0.15) based negative temperature coefficient (NTC) materials are prepared by co-precipitation method. The replacement of Mn by Sr plays a critical role in controlling the lattice parameter, relative density, microstructure, and electrical properties. The lattice parameter and relative density increase with the increase of Sr content. A small amount of Sr restrains the grain growth and increases the bulk density. Moreover, the room resistivity ρ25, material constant B25/50, activation energy Ea, and temperature coefficient α values of MCNS ceramics are influenced by the Sr content and ranged in 1535.0-2053.6 Ω·cm, 3654-3709 K, 0.3149-0.3197 eV, and (-4.173%)-(-4.111%), respectively. The X-ray photoelectron spectroscopy (XPS) results explain the transformation of MCNS ceramics from n- to p-type semiconductors. The conduction could arise from the hopping polaron between Mn3+/Mn4+ and Co2+/Co3+ in the octahedral sites. The impedance data analysis also discusses the conduction mechanism of the MCNS ceramic, whereas grain resistance dominates the whole resistance of the samples. Furthermore, the aging coefficient (ΔR/R) of MCNS ceramics is found to be < 0.2%, which indicates the stable distribution of cations in the spinel. Finally, the MCNS ceramics demonstrate excellent thermal durability with < 1.3% of resistance shift after100 thermal shock cycles.

Publisher

Tsinghua University Press

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