We theoretically and experimentally investigate magnetization reversal and associated spin-wave dynamics of isolated threefold vertices that constitute a Kagome lattice. The three permalloy macrospins making up the vertex have an elliptical cross section and a uniform thickness. We study the dc magnetization curve and the frequency versus field curves (dispersions) of those spin-wave modes that produce the largest response. We also investigate each macrospin reversal from a dynamic perspective, by performing micromagnetic simulations of the reversal processes, and revealing their relationships to the soft-mode profile calculated at the equilibrium state immediately before reversal. The theoretical results are compared with the measured magnetization curves and ferromagnetic resonance spectra. The agreement achieved suggests that a much deeper understanding of magnetization reversal and accompanying hysteresis can be achieved by combining theoretical calculations with static and dynamic magnetization experiments.
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Work at Northwestern was supported by the NSF under Grant No. DMR 1507058. Work at the University of Kentucky was supported by the NSF under Grant No. DMR 1506979. Use was made of the Center for Nanoscale Materials, an Office of Science user facility, which is supported by DOE, Office of Science, Basic Energy Science under Contract No. DE-AC02-06CH11357.
Montoncello, F.; Giovannini, L.; Bang, Wonbae; Ketterson, J. B.; Jungfleisch, M. B.; Hoffmann, A.; Farmer, Barry W.; and De Long, Lance E., "Mutual Influence Between Macrospin Reversal Order and Spin-Wave Dynamics in Isolated Artificial Spin-Ice Vertices" (2018). Physics and Astronomy Faculty Publications. 576.