发表机构
Faculty of Physics, University of Białystok; Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf; Faculty of Physics, Adam Mickiewicz University; Institute of Physics Polish Academy of Sciences（比亚韦斯托克大学物理学院; 德累斯顿-罗斯多夫亥姆霍兹中心离子束物理与材料研究所; 亚当·密茨凯维奇大学物理学院; 波兰科学院物理研究所）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文研究[Re/Co/Pt]₂₀多层膜中由面内外磁场诱导的自旋波冻结效应，结合VNA-FMR、BLS实验及微磁模拟，揭示其色散关系演化规律，构建了一致的物理图像。
AI 中文摘要
自旋波（SW）冻结现象发生在薄膜磁性系统的Damon-Eshbach模式中，此时自旋波的相速度和群速度均趋近于零，波停止振荡和移动，保持其形状为畴结构图案。该效应与自旋重取向转变相关，自旋重取向转变是指磁化构型在均匀面内状态与具有面外磁化分量的畴结构状态之间发生变化的过程。本文中，我们研究了[Re/Co/Pt]₂₀磁性多层膜中的自旋波冻结效应，该效应由改变面外外磁场诱导。研究对象为品质因子Q（单轴各向异性能与退磁能的比值）分别大于1和小于1的纳米结构。在这些多层膜中观察到了具有面外磁化分量的畴结构。通过超导量子干涉器件（SQUID）测量的平行静态磁化曲线中，临界场表现为饱和场Hₛ^∥，该临界场也在依赖于磁场的矢量网络分析仪铁磁共振（VNA-FMR）实验中显现，VNA-FMR用于测量均匀磁化振荡。布里渊光散射（BLS）光谱针对多个波矢值和多个磁场值进行记录，以探测色散关系的磁场演化。微磁模拟可获得完整的色散关系，其与VNA-FMR和BLS结果吻合良好。在Hₛ^∥附近，模拟的色散关系趋近于自旋波冻结的条件。在Hₛ^∥以下，低频和高频VNA-FMR模式分别与畴壁内和畴内的磁化振荡相关。静态和动态行为的实验结果结合微磁模拟，为所研究的多层膜构建了整体一致的图像。
英文摘要
The phenomenon of spin wave (SW) freezing occurs in the Damon-Eshbach mode in thin film magnetic systems, when SW phase and group velocities both go to zero, and the wave ceases to oscillate and move, preserving its shape as a domain structure pattern. This effect is related to the spin reorientation transition, where the magnetization configuration changes between the homogeneous in-plane state and domain structure with the out-of-plane magnetization component state. Here, we study the SW freezing effect in [Re/Co/Pt]$_{20}$ magnetic multilayers, induced by varying the in-plane external magnetic field. The studies were performed on nanostructures with the quality factor $Q$ (ratio of uniaxial anisotropy to demagnetization energies) greater and smaller than one. Domain structures with an out-of-plane magnetization component were observed in these multilayers. The critical field, visible as the saturation field $H_s^{||}$ in the parallel static magnetization curve measured by superconducting quantum interference device (SQUID), is also manifested in the field-dependent vector-network-analyzer ferromagnetic resonance (VNA-FMR) experiment, which measures the homogeneous magnetization oscillations. Brillouin Light Scattering (BLS) spectra, recorded for several values of wave vectors and several field values, probed the field-evolution of the dispersion relation. Micromagnetic simulations allow one to obtain a full dispersion, in good agreement with VNA-FMR and BLS results. Around $H_s^{||}$ the simulated dispersion relations approach the conditions for SW freezing. Below $H_s^{||}$ low and high frequency VNA-FMR modes are related to magnetization oscillations inside domain walls and within domains, respectively. The experimental results of static and dynamic behavior, together with micromagnetic simulations, create an overall consistent picture of the investigated multilayers.
CommentsAccepted for publication in Physical Review B
