arXiv subjects

Jayaseelan Dhakshinamoorthy

Publications and source records attributed to Jayaseelan Dhakshinamoorthy.

2 recordsLinked to original sources

arXiv2026

Deterministic Helicity Locking of Bloch Skyrmions in Centrosymmetric Systems

Magnetic skyrmions in centrosymmetric materials exhibit Bloch-type spin textures with degenerate helicity states due to the absence of Dzyaloshinskii Moriya interaction (DMI), resulting in random nucleation and uncontrolled chirality. Here, we present a comprehensive micromagnetic study demonstrating a fully DMI free strategy for deterministic helicity control by interfacing ferromagnetic (FM) stripes or notch structures with centrosymmetric magnetic (CM) films. We first show that a geometrically constrained configuration comprising two FM stripes with opposite in-plane magnetizations stabilizes skyrmions with a selected helicity, either clockwise (CW) or counterclockwise (CCW). We further extend this concept to achieve deterministic nucleation of CW or CCW skyrmions using current pulses applied to an FM notch patterned on the CM film. The combined effects of the FM stripe/notch geometry and interfacial exchange coupling generate dipolar fields that lift the helicity degeneracy, enabling controlled formation of skyrmions with fixed chirality. These results establish FM/CM heterostructures as a robust, DMI-free platform for deterministic generation and guided motion of helicity-locked skyrmions, opening new pathways for advanced spintronic applications.

cond-mat.other↗

arXiv2023

Manipulation of hybrid skyrmion dynamics by step DMI approach

The dynamic behavior of non-collinear atomic spin arrangements in a topologically protected magnetic skyrmion plays a pivotal role in potential future spintronic technologies, including racetrack memory based ultra-high-density storage devices. However, the topological nature of the skyrmion comes with an unwanted skyrmion Hall effect (SkHE) that poses a significant challenge in the practical application. Here we present a detailed micromagnetic simulation study that delves into the controlled manipulation of skyrmion dynamics through a subtle engineering of Dzyaloshinskii-Moriya interaction (DMI) in a hybrid skyrmion racetrack. In particular, we introduce a gradient variation of bulk and interfacial DMI that results into a parabolic trajectory of Skyrmion Hall angle (SkHA), thereby allowing us to find a critical DMI ratio with almost zero SkHE. Most importantly, we present a novel approach involving engineering of a racetrack with strategically placed step DMI regions that gives us a meticulous control over the size and speed of the hybrid skyrmions. The present study gives a new direction for the simultaneous realization of stable skyrmions without SkHE and increased skyrmion speed with optimized DMI engineering.

cond-mat.mes-hall↗