title: Current-Induced Generation and Synchronous Motion of Highly Packed Coupled Chiral Domain Walls.
abstract: Chiral domain walls of Neel type emerge in heterostructures that include heavy metal (HM) and ferromagnetic metal (FM) layers owing to the Dzyaloshinskii-Moriya (DM) interaction at the HM/FM interface. In developing storage class memories based on the current induced motion of chiral domain walls, it remains to be seen how dense such domain walls can be packed together. Here we show that a universal short-range repulsion that scales with the strength of the DM interaction exists among chiral domain walls. The distance between the two walls can be reduced with the application of the out-of-plane field, allowing the formation of coupled domain walls. Surprisingly, the current driven velocity of such coupled walls is independent of the out-of-plane field, enabling manipulation of significantly compressed coupled domain walls using current pulses. Moreover, we find that a single current pulse with optimum amplitude can create a large number of closely spaced domain walls. These features allow current induced generation and synchronous motion of highly packed chiral domain walls, a key feature essential for developing domain wall based storage devices.
authors.affiliation: Instituto de Ciencia de Materiales de Madrid, CSIC , Madrid 28049, Spain.
authors.forename: Rafael
authors.initials: R
authors.lastname: P Del Real
authors.affiliation: University of Salamanca , Plaza de los Caidos s/n, E-37008 Salamanca, Spain.
authors.forename: Victor
authors.initials: V
authors.lastname: Raposo
authors.affiliation: University of Salamanca , Plaza de los Caidos s/n, E-37008 Salamanca, Spain.
authors.forename: Eduardo
authors.identifier: 0000-0003-2960-5508
authors.initials: E
authors.lastname: Martinez
authors.affiliation: Department of Physics, The University of Tokyo , Bunkyo, Tokyo 113-0033, Japan.|National Institute for Materials Science , Tsukuba 305-0047, Japan.
authors.forename: Masamitsu
authors.identifier: 0000-0003-2134-2563
authors.initials: M
authors.lastname: Hayashi
keywords: Chiral domain walls; Dzyaloshinskii−Moriya interaction; spin orbit coupling; storage class memories