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DOE OSTI · 1992459

Interfacial magnetic vortex formation in exchange-coupled hard-soft magnetic bilayers

Zhang, X. H.·Gao, T. R.·Fang, L.·Fackler, S.·Borchers, J. A.·Kirby, B. J.·Maranville, B. B.·Lofland, S. E.·N'Diaye, A. T.·Arenholz, E.·Ullah, A.·Cui, J.·Skomski, R.·Takeuchi, I.
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Abstract

The exchange coupling between a hard magnetic layer MnBi and a soft magnetic layer Co-Fe has been found to significantly improve the maximum energy product. In this work, the spin structure of exchange coupled MnBi:Co-Fe bilayers is experimentally investigated by X-ray magnetic circular dichroism (XMCD) and polarized neutron reflectometry (PNR). We find that the out-of-plane magnetization reversal process of the MnBi:Co-Fe bilayer structure involves formation of a curling-type twisting of the magnetization in the film plane at low or intermediate reversal fields. Additionally, micromagnetic simulations are further performed to provide a detailed view of the spins at the curling center. Reminiscent of chiral spin structures known as spin bobbers, this curling in the exchange-coupled hard-soft magnetic bilayers is a new type of skyrmionic spin structure and worth further investigation.

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36 MATERIALS SCIENCE

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Zhang, X. H., Gao, T. R., Fang, L., Fackler, S., Borchers, J. A., Kirby, B. J., Maranville, B. B., Lofland, S. E., N'Diaye, A. T., Arenholz, E., Ullah, A., Cui, J., Skomski, R., Takeuchi, I.. 2022-06-18. Interfacial magnetic vortex formation in exchange-coupled hard-soft magnetic bilayers. https://doi.org/10.1016/j.jmmm.2022.169627

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