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arXiv 2008.02013cond-mat.mtrl-sci
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体心立方Fe-Mn合金温度相关磁化学相互作用的从头算模型

Ab-initio based models for temperature-dependent magneto-chemical interplay in bcc Fe-Mn alloys

Anton Schneider, Chu-Chun Fu, Osamu Waseda, Cyrille Barreteau, Tilmann Hickel

摘要:

体心立方(bcc)Fe-Mn系统具有复杂的非典型磁性,这是由于Mn的3d半充满带引起的。我们提出了有效的相互作用模型,这些合金,其中包含原子自旋和化学变量。它们的参数化的一组关键的密度泛函理论(DFT)的数据,包括非共线的磁性配置是必不可少的。两种不同的方法,即知识驱动和机器学习方法已被用于拟合。在原子蒙特卡罗模拟中采用这些模型能够预测Fe-Mn合金的磁性和热力学性质,以及它们的耦合,作为温度的函数。这包括居里温度随Mn浓度的增加而降低,混合焓的温度演化及其与合金磁化强度的相关性。此外,超越无缺陷系统,我们确定了空位和Mn原子之间的结合自由能,这是控制Fe-Mn合金中原子输运的关键参数。

英文摘要:

Body-centered cubic (bcc) Fe-Mn systems are known to exhibit a complex and atypical magnetic behaviour from both experiments and 0 K electronic-structure calculations, which is due to the half-filled 3d-band of Mn. We propose effective interaction models for these alloys, which contain both atomic spin and chemical variables. They were parameterized on a set of key density functional theory (DFT) data, with the inclusion of non-collinear magnetic configurations being indispensable. Two distinct approaches, namely a knowledge-driven and a machine-learning approach have been employed for the fitting. Employing these models in atomic Monte Carlo simulations enables the prediction of magnetic and thermodynamic properties of the Fe-Mn alloys, and their coupling, as functions of temperature. This includes the decrease of Curie temperature with increasing Mn concentration, the temperature evolution of the mixing enthalpy and its correlation with the alloy magnetization. Also, going beyond the defect-free systems, we determined the binding free energy between a vacancy and a Mn atom, which is a key parameter controlling the atomic transport in Fe-Mn alloys.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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