Abstract
The dynamic motion of topological defects in magnets induces an emergent electric field, as exemplified by the continuous flow of skyrmion vortices. However, the electrodynamics underlying this emergent field remains poorly understood. In this context, magnetic domain walls—one-dimensional topological defects with two collective modes, sliding and spin-tilt—offer a promising platform for exploration. Here we demonstrate that the dissipative motion of domain walls under oscillatory current excitation generates an emergent electric field. We image domain patterns and quantify the domain-wall length under applied magnetic fields in mesoscopic devices based on the magnetic Weyl semimetal NdAlSi. These devices exhibit exceptionally strong domain-wall scattering and a pronounced emergent electric field, as observed in the imaginary component of the complex impedance. Spin dynamics simulations reveal that domain-wall sliding dominates over spin-tilting, in which the phase delay of the domain-wall motion with respect to the driving force impacts the emergent electric field. Our findings establish domain-wall dynamics as a platform for studying emergent electromagnetic fields and motivate further investigations of the coupled motion of magnetic solitons and conduction electrons.
| Original language | English |
|---|---|
| Journal | Nature Physics |
| DOIs | |
| State | Accepted/In press - 2026 |
Funding
We acknowledge M. Birch, I. Belopolski, P. R. Baral, G. Chang, S. Sen, A. Ozawa, N. Nagaosa and T.-h. Arima for fruitful discussions, and the RIKEN CEMS Semiconductor Science Research Support Team for technical assistance. R.Y. was supported by the JSPS (KAKENHI Grant Nos. 22K20348, 23K13057, 24H01604 and 25K17336), the Japan Science and Technology Agency (JST) (PRESTO Grant No. JPMJPR259A), the Foundation for the Promotion of Material Science and Technology of Japan, the Yashima Environment Technology Foundation, the Yazaki Memorial Foundation for Science and Technology, and the ENEOS Tonengeneral Research/Academic Foundation. Y.F. was supported by the JST (PRESTO Grant No. JPMJPR2597). S.O. was supported by the JSPS (KAKENHI Grant Nos. 22K13998 and 23K25816) and the JST (PRESTO Grant No. JPMJPR2595). T.Y. was supported by the JSPS (KAKENHI Grant No. 24K00566) and the JST (PRESTO Grant No. JPMJPR235B). Y. Taguchi was supported by the JST (CREST Grant No. JPMJCR20T1) and the RIKEN TRIP initiative (Many-body Electron Systems and Advanced General Intelligence for Science Program). Y. Tokura was supported by the JSPS (KAKENHI Grant No. 23H05431) and the JST (CREST Grant No. JPMJCR1874). M.H. was supported by the JSPS (KAKENHI Grant Nos. 21K13877, 22H04463, 23H05431 and 24H01607), the JST (CREST Grant No. JPMJCR20T1 and FOREST Grant No. JPMJFR2238), the Fujimori Science and Technology Foundation, the New Materials and Information Foundation, the Murata Science Foundation, the Mizuho Foundation for the Promotion of Sciences, the Yamada Science Foundation, the Hattori Hokokai Foundation, the Iketani Science and Technology Foundation, the Mazda Foundation, the Casio Science Promotion Foundation, the Takayanagi Foundation, and Inamori Foundation. M.H. is also supported by the JST as part of Adopting Sustainable Partnerships for Innovative Research Ecosystem (ASPIRE; Grant No. JPMJAP2426). M.H. is supported by the Deutsche Forschungsgemeinschaft (German Research Foundation) through Transregio (Grant No. TRR 360 - 492547816). O.A.T. acknowledges support from the Australian Research Council (Grant Nos. DP200101027 and DP240101062) and an NCMAS grant. This work is based on experiments performed at the Japan Research Reactor 3 (proposal no. 23515). This research was sponsored by the Laboratory Directed Research and Development Program of Oak Ridge National Laboratory, managed by UT-Battelle, LLC, for the US Department of Energy. This Article has been authored by UT-Battelle, LLC, under contract DE-AC05-00OR22725 with the US Department of Energy (DOE). The US government retains and the publisher, by accepting the article for publication, acknowledges that the US government retains a non-exclusive, paid-up, irrevocable, worldwide licence to publish or reproduce the published form of this Article, or allow others to do so, for US government purposes. The DOE will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan ( www.energy.gov/doe-public-access-plan ).