We provide a systematic analysis of finite-temperature magnetic properties of random alloys ${\mathrm{Fe}}_x{\mathrm{Ni}}_{1-x}$ with the face-centered-cubic structure over a broad concentration range $x$. By means of the spin-polarized relativistic Korringa-Kohn-Rostoker method we calculate the electronic structure of disordered iron-nickel alloys and discuss how a composition change affects magnetic moments of Fe and Ni and the density of states. We investigate how the Curie temperature depends on Fe concentration using conventional approaches, such as mean-field approximation or Monte Carlo simulations, and dynamic spin-fluctuation theory. Being devised to account for spin fluctuations explicitly, the latter method shows the best fit to experimental results.

中文翻译：

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随机铁镍合金：从第一性原理到动态自旋涨落理论

我们提供随机合金有限温度磁性能的系统分析 ${铁}_X{你}_{1-X}$ 在广泛的浓度范围内具有面心立方结构 $X$. 通过自旋极化相对论 Korringa-Kohn-Rostoker 方法，我们计算了无序铁镍合金的电子结构，并讨论了成分变化如何影响 Fe 和 Ni 的磁矩和态密度。我们使用常规方法（例如平均场近似或蒙特卡罗模拟）和动态自旋波动理论研究居里温度如何取决于 Fe 浓度。后一种方法被设计为明确考虑自旋波动，显示出最适合实验结果。