ABSTRACT First-principles calculations of density functional theory (DFT) using the generalized gradient approximation (GGA) and generalized gradient approximation with the Hubbard U (GGA + U) for the exchange-correlation energy functional are used to investigate the structural, electronic, and magnetic properties of the spinel system in the range . High-temperature series expansions (HTSE) combined with the Padé approximants (PA) method and mean field theory (MFT) are applied to the systems. The lattice parameter and magnetic moment of Fe and Ni ions increase when Cd content x increases. Density of States (DOS) calculations show that the has a semiconductor behaviour. The obtained theoretical results show that the Curie temperature decreases with x. These obtained results are in agreement with experimental ones.

中文翻译：

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Cd-Ni 尖晶石铁氧体的结构和磁性能：密度泛函理论计算和高温系列扩展

摘要 密度泛函理论 (DFT) 的第一性原理计算使用广义梯度近似 (GGA) 和使用 Hubbard U (GGA + U) 进行交换相关能量泛函的广义​​梯度近似，用于研究结构、电子和尖晶石系统的磁性能范围。高温级数展开 (HTSE) 结合帕德近似 (PA) 方法和平均场理论 (MFT) 应用于系统。当Cd含量x增加时，Fe和Ni离子的晶格参数和磁矩增加。态密度 (DOS) 计算表明 具有半导体行为。得到的理论结果表明，居里温度随x而降低。这些得到的结果与实验结果一致。