Phase-resolved imaging of edge-mode spin waves using scanning transmission x-ray microscopy

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• 作者：C. Cheng ; W. Cao ; W.E. Bailey¹
• 刊名：Journal of Magnetism and Magnetic Materials
• 出版年：2017
• 出版时间：15 February 2017
• 年：2017
• 卷：424
• 期：Complete
• 页码：12-15
• 全文大小：519 K

文摘

We have imaged the excitation of small-amplitude spin-wave eigenmodes, localized within ∼100 nm of the vertices of nanoscale Ni₈₁Fe₁₉ ellipses, using time-resolved scanning transmission x-ray microscopy (STXM) at 2 GHz and resolution of 70 nm. Taking advantage of the buried-layer sensitivity of STXM, we find that the magnetization precession at the two vertices changes from predominantly in-phase to out-of-phase in samples with and without a conductive layer deposited over the ellipses. As a plausible interpretation for the reversal in phase, we propose that unexpectedly strong Oersted fields are generated in the discontinuous overlayer, although effects of edge roughness cannot be fully excluded. The results demonstrate the capabilities of STXM to image small-amplitude, GHz magnetization dynamics with the potential to map rf magnetic fields on the nanoscale.