Abstract The comparison of the magnetic, electronic, and optical properties of the spinel transition-metal oxides AB2O4 (A, B = Fe, Mn) and their relationship with the structure and composition were studied within DFT-GGA+U approximation. The spinels were considered both in the normal and inverse structure. We have found that regardless of composition and structure, the studied spinels are ferrimagnetic with antiparallel magnetic moments on A- and B-site cations. Electronic and structural properties of spinels depend on the composition: FeMn2O4 has a tetragonal structure and half-metallic properties; however, in the inverse FeMn2O4, the bandgap opens for the spin-up channel. MnFe2O4 is a cubic insulator with a bandgap of about 1.5 eV, which decreases in the inverse structure. The superexchange constants estimate within the simple indirect coupling model and have values close to the experimental ones. The total magnetization of FeMn2O4 is drop-down to zero under hydrostatic pressure above 60 GPa due to the strong dependence of the magnetic moment of octahedral manganese ion on the pressure. The microscopic mechanisms of the relationship between the structure, composition and properties are studied.

中文翻译：

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AB2O4 (A, B= Mn, Fe) 尖晶石的磁性、电子和光学性质的从头算比较研究

摘要 在 DFT-GGA+U 近似下研究了尖晶石过渡金属氧化物 AB2O4 (A, B = Fe, Mn) 的磁、电子和光学性质的比较及其与结构和组成的关系。尖晶石被认为是正常和反相结构。我们发现，无论成分和结构如何，所研究的尖晶石都是亚铁磁性的，在 A 位和 B 位阳离子上具有反平行的磁矩。尖晶石的电子和结构特性取决于成分：FeMn2O4 具有四方结构和半金属特性；然而，在逆 FeMn2O4 中，自旋通道的带隙打开。MnFe2O4 是立方绝缘体，带隙约为 1.5 eV，在逆结构中减小。简单间接耦合模型中的超交换常数估计值接近实验值。由于八面体锰离子的磁矩对压力的强烈依赖性，FeMn2O4 的总磁化强度在 60 GPa 以上的静水压力下下降到零。研究了结构、组成和性能之间关系的微观机制。