Thermal Evolution of Skyrmions in Synthetic Ferrimagnets of Co/Gd Heterostructure for Topological Spintronic Applications

TL;DR

This study investigates the thermal behavior of skyrmions in Co/Gd synthetic ferrimagnets, demonstrating room-temperature stability and developing a microscopic model to understand their magnetic phase evolution for spintronic use.

Contribution

It provides the first systematic analysis of temperature and field effects on skyrmions in Co/Gd SFiMs and introduces a microscopic spin model that matches experimental results.

Findings

Skyrmions of 70 nm radius are stable at room temperature.

The Co and Gd sublattices significantly influence temperature-dependent magnetization.

A microscopic spin model successfully reproduces experimental magnetic phase behavior.

Abstract

Synthetic ferrimagnetic (SFiM) multilayers offer a versatile platform for hosting skyrmions with tunable magnetic properties, combining the advantages of ferromagnets and antiferromagnets. Unlike synthetic antiferromagnets, SFiMs retain a finite magnetization that allows direct observation of magnetic textures while still benefiting from reduced dipolar fields and a suppressed skyrmion Hall effect. However, a systematic investigation of their temperature and field dependent magnetization evolution, including the labyrinthine-to-skyrmion transition in Co/Gd-based SFiMs, remains less explored. Here, we demonstrate the stabilization of 70 nm-radius skyrmions at room temperature and reveal how the Co and Gd sublattices influence the temperature-dependent net magnetization. Further, we develop a microscopic spin model for SFiM incorporating the relevant magnetic interactions, which reproduces the experimental observations and captures the temperature-dependent magnetic phase evolution. This framework highlights the interplay of fundamental interactions controlling skyrmion stability in SFiM and provides a pathway for engineering heterostructures for topological spintronic applications.