Encoding and multiplexing information signals in magnetic multilayers with fractional skyrmion tubes

TL;DR

This paper demonstrates the numerical creation and control of fractional skyrmion tubes in magnetic multilayers, proposing their use for multiplexed and pipelined information encoding in spintronic devices, with verified stability and transmission methods.

Contribution

It introduces fractional skyrmion tubes in magnetic multilayers and proposes a device architecture for their use in multiplexed and pipelined information transmission.

Findings

Numerical verification of stable fractional skyrmion tubes in multilayers.

Proposal of a multiplexing device using FSTs for information encoding.

Demonstration of pipelined transmission and automatic demultiplexing of signals.

Abstract

Tailored magnetic multilayers (MMLs) provide skyrmions with enhanced thermal stability, leading to the possibility of skyrmion-based devices for room temperature applications. At the same time, the search for additional stable topological spin textures has been under intense research focus. Besides their fundamental importance, such textures may expand the information encoding capability of spintronic devices. However, fractional spin texture states within MMLs in the vertical dimension have yet to be investigated. In this work, we demonstrate numerically fractional skyrmion tubes (FSTs) in a tailored MML system. We subsequently propose to encode sequences of information signals with fractional skyrmion tubes (FSTs) as information bits in a tailored MML device. Micromagnetic simulations and theoretical calculations are used to verify the feasibility of hosting distinct FST states within a single device, and their thermal stability is investigated. A multilayer multiplexing device is proposed, where multiple sequences of the information signals can be encoded and transmitted based on the nucleation and propagation of packets of FSTs. Finally, pipelined information transmission and automatic demultiplexing is demonstrated by exploiting the skyrmion Hall effect and introducing voltage-controlled synchronizers and width-based track selectors. The findings indicate that FSTs can be potential candidates as information carriers for future spintronic applications.