We explored robust magnetization dynamics in ferrimagnetic Gd_x(FeCo)_1−x nanospheres of Gd compositions ranging from x = 0 to 0.44 at finite T = 0 – 1200 K temperatures using two-sublattice atomistic simulations based on the stochastic Landau-Lifshitz-Gilbert equation. It was found that the magnetization compensation and angular-momentum compensation temperatures vary remarkably with x and that the former temperature is always lower than the latter. Also, it was found that neither compensation temperature exists below a specific Gd composition of x = 0.22, but above which, both exist and increase with x. The ferromagnetic resonance (FMR) frequency remarkably increases at the angular momentum compensation composition, whereas the FMR frequency does not reach zero at the magnetization compensation composition. The significant difference in the FMR frequency between the two characteristic compensation points is ascribed to the contrasting effective gyromagnetic ratios of Gd and FeCo. Our present atomistic simulation study well reproduced the earlier experimental observations of such dynamic behaviors at both the angular-momentum and magnetization compensation points, which observations cannot be explained by the existing Kittel and Wangsness models. This work provides a better understanding of robust dynamic behaviors of ferrimagnetic nanospheres as functions of temperature and constituent sublattice composition, especially at and near the characteristic compensation points.

我们 使用基于随机 Landau-Lifshitz-Gilbert 的两个亚晶格原子模拟，探索了 在有限T = 0 – 1200 K 温度下，Gd 成分范围从x = 0 到 0.44 的亚铁磁性 Gd _x (FeCo) _{1− x}纳米球的稳健磁化动力学方程。发现磁化补偿和角动量补偿温度随x变化显着，且前者的温度总是低于后者。此外，发现补偿温度不低于x = 0.22的特定 Gd 成分，但高于该温度，两者都存在并随x增加. 铁磁共振 (FMR) 频率在角动量补偿成分处显着增加，而 FMR 频率在磁化补偿成分处不会达到零。两个特征补偿点之间 FMR 频率的显着差异归因于 Gd 和 FeCo 的对比有效旋磁比。我们目前的原子模拟研究很好地再现了早期在角动量和磁化补偿点处对这种动态行为的实验观察，这些观察无法通过现有的 Kittel 和 Wangsness 模型来解释。这项工作提供了更好地理解亚铁磁性纳米球作为温度和组成亚晶格组成的函数的稳健动态行为，