title: Creep turns linear in narrow ferromagnetic nanostrips.
abstract: The motion of domain walls in magnetic materials is a typical example of a creep process, usually characterised by a stretched exponential velocity-force relation. By performing large-scale micromagnetic simulations, and analyzing an extended 1D model which takes the effects of finite temperatures and material defects into account, we show that this creep scaling law breaks down in sufficiently narrow ferromagnetic strips. Our analysis of current-driven transverse domain wall motion in disordered Permalloy nanostrips reveals instead a creep regime with a linear dependence of the domain wall velocity on the applied field or current density. This originates from the essentially point-like nature of domain walls moving in narrow, line- like disordered nanostrips. An analogous linear relation is found also by analyzing existing experimental data on field-driven domain wall motion in perpendicularly magnetised media.
authors: Department of Solid State Sciences, Ghent University, Krijgslaan 281/S1, 9000 Ghent, Belgium.|Department of Electrical Energy, Systems and Automation, Ghent University, 9000 Ghent, Belgium.
authors: Jonathan
authors: J
authors: Leliaert
authors: Department of Electrical Energy, Systems and Automation, Ghent University, 9000 Ghent, Belgium.
authors: Ben
authors: B
authors: Van de Wiele
authors: Department of Solid State Sciences, Ghent University, Krijgslaan 281/S1, 9000 Ghent, Belgium.
authors: Arne
authors: A
authors: Vansteenkiste
authors: COMP Centre of Excellence and Helsinki Institute of Physics, Department of Applied Physics, Aalto University, P.O. Box 11100, FIN-00076 Aalto, Espoo, Finland.
authors: Lasse
authors: L
authors: Laurson
authors: Istituto Nazionale di Ricerca Metrologica, Strada delle Cacce 91, 10135 Torino, Italy.|ISI Foundation, Via Alassio 11/c, 10126, Torino, Italy.
authors: Gianfranco
authors: G
authors: Durin
authors: Department of Electrical Energy, Systems and Automation, Ghent University, 9000 Ghent, Belgium.
authors: Luc
authors: L
authors: Dupré
authors: Department of Solid State Sciences, Ghent University, Krijgslaan 281/S1, 9000 Ghent, Belgium.
authors: Bartel
authors: B
authors: Van Waeyenberge