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
