AI 中文总结
研究Bi掺杂铁石榴石薄膜从均匀到条纹畴转变中的自旋波软化。采用磁力显微镜、μ-BLS测量及微磁模拟等方法，揭示了相关现象及规律，确立了该材料为研究自旋波等相关特性的低阻尼模型平台。
AI 中文摘要
均匀相和纹理相之间转变的自旋波光谱能深入了解对称性破缺物理和自组装磁振子带。然而，实验需要低阻尼、明确纹理和光谱可及性的材料平台。本文研究了具有垂直磁各向异性的Bi掺杂铁石榴石薄膜，它随面内磁场发生从均匀到条纹畴的转变。通过磁力显微镜实空间成像揭示了与面内场对齐的场可重定向条纹畴，利用热微聚焦布里渊光散射（μ-BLS）倒易空间测量揭示了转变附近低频自旋波分支的软化及条纹畴态中额外模式的出现。计算色散关系确定了Damon-Eshbach几何（k⊥M）中的有限k软化，其波长与转变时条纹周期性匹配。此外，μ-BLS光谱模型再现了选定固定场下的测量模式频率和相对强度。微磁模拟捕捉了条纹态的场驱动形成并再现了实验热μ-BLS光谱。我们的发现确立了具有PMA的BiYIG作为研究自旋波冻结、条纹畴模式和可重构磁振子带结构的低阻尼模型平台。
英文摘要
Spin-wave spectra across transitions between uniform and textured phases can offer deep insight into both symmetry-breaking physics and self-assembled magnonic bands. However, experiments require a material platform that combines low damping, well-defined textures, and spectroscopic access. Here, we study a Bi-doped iron-garnet film with perpendicular magnetic anisotropy (PMA), which undergoes a uniform-to-stripe-domain transition as a function of in-plane magnetic field. Real-space imaging by magnetic force microscopy reveals field-reorientable stripe domains aligned with the in-plane field, while reciprocal-space measurements using thermal microfocused Brillouin light scattering ($μ$-BLS) reveal the softening of a low-frequency spin-wave branch near the transition and the appearance of additional modes in the stripe-domain state. Calculated dispersion relations identify finite-$k$ softening in the Damon-Eshbach geometry ($k \perp M$), with the corresponding wavelength matching the stripe periodicity at the transition. In addition, a $μ$-BLS spectral model reproduces the measured mode frequencies and relative intensities at selected fixed fields. Micromagnetic simulations capture the field-driven formation of the stripe state and reproduce the experimental thermal $μ$-BLS spectra. Our findings establish BiYIG with PMA as a model low-damping platform for studying spin-wave freezing, stripe-domain modes, and reconfigurable magnonic band structures.
CommentsMain text: 8 pages, 6 figures. Supplementary Material: 4 pages, 4 figures
