Strongly reduced band gap in NiMn2O4 due to cation exchange

Please use this identifier to cite or link to this item: https://ir.lib.ncu.edu.tw/handle/987654321/107871

Title:	Strongly reduced band gap in NiMn2O4 due to cation exchange
Authors:	徐翰;Huang, Jhih-Rong;Hsu, Han;Cheng, Ching
Contributors:	理學院物理學系
Keywords:	Condensed matter: electronic structure, electrical, magnetic, and optical properties;Conductivity phenomena in semiconductors and insulators;Density functional calculation;Electron density of states and band structure of crystalline solids;Electron states;Electronic transport in condensed matter;Exact sciences and technology;Low-field transport and mobility;piezoresistance;Nickel manganite;Other inorganic compounds;Physics
Date:	2014-05-01
Issue Date:	2026-04-23 14:27:42 (UTC+8)
Publisher:	Elsevier;Amsterdam: Elsevier B.V
Abstract:	摘要： NiMn2O4 is extensively used as a basis material for temperature sensors due to its negative temperature coefficient of resistance (NTCR), which is commonly attributed to the hopping mechanism involving coexisting octahedral-site Mn4+ and Mn3+. Using density-functional theory + Hubbard U calculations, we identify a ferrimagnetic inverse spinel phase as the collinear ground state of NiMn2O4. By a 12.5% cation exchange, a mixed phase with slightly higher energy can be constructed, accompanied by the formation of an impurity-like band in the original 1eV band gap. This impurity-like band reduces the gap to 0.35eV, suggesting a possible source of NTCR. •Density functional based calculations were used to study collinear phase of NiMn2O4.•The ground-state structure is a ferrimagnetic inverse spinel phase.•The tetrahedral and octahedral Mn cations have ferromagnetic interactions.•A 12.5% cation exchange introduces an impurity-like band in the original 1eV gap.•The 0.35eV gap suggests a source of negative temperature coefficient of resistance. 出版者： Amsterdam: Elsevier B.V 出版日期： 2014-05-01 出處： Journal of magnetism and magnetic materials, 2014-05, Vol.358-359, p.149-152 版權： 2014 Elsevier B.V. 版權： 2015 INIST-CNRS 識別號： ISSN: 0304-8853 識別號： DOI: 10.1016/j.jmmm.2014.01.048 識別號： CODEN: JMMMDC
Appears in Collections:	[Department of Physics] journal & Dissertation

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