Encoding and Multiplexing Information Signals in Magnetic Multilayers with Fractional Skyrmion Tubes

Tailored magnetic multilayers (MMLs) provide skyrmionswith enhancedthermal stability, leading to the possibility of skyrmion-based devicesfor room-temperature applications. At the same time, the search foradditional stable topological spin textures has been under intenseresearch focus. Besides their fundamental importance, such texturesmay expand the information encoding capability of spintronic devices.However, fractional spin texture states within MMLs in the verticaldimension are yet to be investigated. In this work, we demonstratenumerically fractional skyrmion tubes (FSTs) in a tailored MML system.We subsequently propose to encode sequences of information signalswith FSTs as information bits in a tailored MML device. Micromagneticsimulations and theoretical calculations are used to verify the feasibilityof hosting distinct FST states within a single device, and their thermalstability is investigated. A multilayer multiplexing device is proposed,where multiple sequences of the information signals can be encodedand transmitted based on the nucleation and propagation of packetsof FSTs. Finally, pipelined information transmission and automaticdemultiplexing are demonstrated by exploiting the skyrmion Hall effectand introducing voltage-controlled synchronizers and width-based trackselectors. The findings indicate that FSTs can be potential candidatesas information carriers for future spintronic applications.