Topological electromotive force from domain-wall dynamics in a ferromagnet

TitleTopological electromotive force from domain-wall dynamics in a ferromagnet
Publication TypeJournal Article
Year of Publication2010
AuthorsYang, SA, Beach, GSD, Knutson, C, Xiao, D, Zhang, Z, Tsoi, M, Niu, Q, MacDonald, AH, Erskine, JL
JournalPhysical Review B
Volume82
Issue5
Pagination054410
Date Published2010/08/10/
Abstract

We formulate a local gauge-invariant theory for the electromotive force induced by domain-wall dynamics in a ferromagnet. We demonstrate that this emf generation is a real-space topological pumping effect. The integral of the emf over one pumping period is a quantized topological invariant which does not depend on the details of the domain-wall configuration nor on its detailed dynamics. Based on our theory, the full instantaneous electric potential distribution can be mapped out by standard electrostatic methods. We also provide further details on our recent experiments which confirmed the emf induced by domain-wall dynamics.