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Vertical shift register using dipolar interaction in magnetic multilayers


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Authors

Fernández-Pacheco, A 
Petit, DCMC 
Cowburn, RP 

Abstract

jats:pA vertical shift register consisting of multi-layered ferromagnetic bars with in-plane magnetization is investigated numerically using macrospin simulations. These layers are anti-ferromagnetically coupled via dipolar interactions and their in-plane aspect ratio determines their anisotropy. A single data bit is represented by a magnetic kink soliton, which forms at the boundary of two anti-parallel domains with opposite phases. It can be propagated bi-directionally using an externally applied rotating magnetic field. The soliton propagation is dependent on the applied field strength, the magnetic anisotropy of the ferromagnetic layers, and the dipolar coupling energies. For the device investigated here, the largest field range for soliton propagation is found to be from 35 Oe to 235 Oe at a lateral aspect ratio of 1.33. The soliton is also subjected to edge effects where it can be either pinned or reflected rather than being expelled from the stack. It is found that by reducing the thickness of the edge layer, these effects can be reduced substantially. By reducing the thickness of the edge layer by 20%, the field range in which the soliton is expelled increases by more than a factor of two.</jats:p>

Description

Keywords

51 Physical Sciences, 5104 Condensed Matter Physics

Journal Title

Journal of Applied Physics

Conference Name

Journal ISSN

0021-8979
1089-7550

Volume Title

118

Publisher

AIP Publishing
Sponsorship
Engineering and Physical Sciences Research Council (EP/M008517/1)
European Research Council (247368)
European Commission (309589)
This project has received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement no. 309589 (M3d), as well as the Seventh Framework Programme ERC Contract No. 247368 (3SPIN). AFP acknowledges funding from an EPSRC Early Career Fellowship, EP/M008517/1 and from the Winton Foundation.