我们提出了一个简单的原子尺度模型,用于描述磁性多层膜中的非共线耦合;这些多层膜具有由 Ru 与 Fe 等铁磁性原子合金化形成的混合间隔层。与以往通过耦合常数的横向涨落来解释非共线耦合的解析模型和微磁模型不同,所提出模型考虑了间隔层内全部三个空间维度上的原子—原子耦合。该新模型能够准确预测宏观双线性和双二次耦合常数对间隔层成分与厚度的依赖关系,表现出远优于横向涨落模型的定量一致性。此外,它甚至对无限刚性的铁磁层也预测出非共线耦合,这超出了以往模型的预测范围。
英文摘要:
We present a simple atomistic model for the description of noncollinear coupling in magnetic multilayers with hybrid spacer layers made of Ru alloyed to ferromagnetic atoms such as Fe. In contrast to previous analytical and micromagnetic models that explain the noncollinear coupling by means of lateral fluctuations in the coupling constant, the presented model accounts for atom-atom coupling in all three spatial dimensions within the spacer layer. The new model is able to accurately predict the dependence of the macroscopic bilinear and biquadratic coupling constants on the spacer-layer composition and thickness, showing much better quantitative agreement than lateral-fluctuation models. Moreover, it predicts noncollinear coupling even for infinitely stiff ferromagnetic layers which goes beyond the predictions of previous models.
偏离平衡位置的共线磁化的进动和阻尼由Landau-Lifshitz-Gilbert方程描述。对于非共线磁化,不知道如何描述阻尼。我们利用第一性原理散射理论研究了重要铁磁合金Ni $_{80}$ Fe $_{20}$的一维横向畴壁的阻尼,并用唯象模型解释了结果.阻尼被发现不仅取决于磁化织构,但也对特定的动力学模式的布洛赫和Néel DW。即使在高度无序的Ni $_{80}$ Fe $_{20}$合金中,也发现阻尼是显著非局部的。
Anisotropic Piezomagnetism in Noncollinear Antiferromagnets
Institute for Materials Research, Tohoku University(东北大学物质材料研究所学);Liberal Arts and Sciences, Toyama Prefectural University(富山县立大学文理学院);Department of Materials Science, Graduate School of Engineering, Osaka Metropolitan University(大阪公立大学工学研究科材料科学系);Center for Spintronics Research Network, Graduate School of Engineering Science, Osaka University(大阪大学工学科学研究科自旋电子学研究网络中心)
Rigorous extension of semilocal collinear functionals to noncollinear DFT using $SU(2)$ rotations
Helmholtz Institut Mainz(亥姆霍兹美因茨研究所);GSI Helmholtzzentrum für Schwerionenforschung GmbH(GSI重离子研究中心有限公司);Institut für Physik, Johannes Gutenberg-Universität Mainz(美因茨约翰内斯·古腾堡大学物理研究所)