Atomistic insights into design of tunable rare-earth ferrimagnets for emerging spintronic memory platforms
Abstract
Structurally amorphous rare earth–transition metal (RE–TM) ferrimagnetic alloys provide a versatile and tunable materials platform for next-generation spintronic technologies, including skyrmion and racetrack-based memory and logic devices. In this work, we present a comprehensive atomistic modelling of spin dynamics study of the composition and temperature-dependent magnetic properties of binary TbCo, GdCo, and ternary TbGdCo alloys. Using Monte Carlo and constrained Monte Carlo methods within the Vampire framework, we systematically investigate net magnetization, magnetization compensation temperature, Curie temperature, restoring torque, free energy, uniaxial magnetic anisotropy, coercivity, domain wall width, and exchange stiffness. Temperature-dependent magnetization curves reveal pronounced rare-earth element sensitivity, with Tb-rich alloys exhibiting higher zero-temperature magnetization and steeper thermal decay due to strong spin–orbit coupling, while Gd-rich alloys show higher Curie temperatures driven by stronger isotropic exchange. The calculated compensation temperatures and Curie temperatures show systematic and opposing trends with rare-earth concentration and agree well with mean-field predictions. Restoring torque and free energy exhibit characteristic sin2θ and sin2θ angular dependencies, respectively, confirming uniaxial anisotropy. The extracted anisotropy follows an unusual Callen-Callen power-law scaling with rare-earth sublattice magnetization, highlighting the intricate nature of these alloys. Domain wall modelling at 0K reveals strong geometry-induced demagnetizing effects that critically influence domain wall width and exchange stiffness. Importantly, the demonstrated ability to independently tune saturation magnetization, anisotropy, and exchange stiffness through rare-earth composition provides a direct pathway to emergent spintronic technologies such as in skyrmionic devices. This enables engineering the skyrmion stability parameter, optimize trade-offs between skyrmion size, stability, and current-driven mobility for skyrmion and other such emergent spintronic memory platforms.
Publication Title
Journal of Magnetism and Magnetic Materials
Recommended Citation
Sriram, K., Bansal, A., Pollard, S., & Dutta, T. (2026). Atomistic insights into design of tunable rare-earth ferrimagnets for emerging spintronic memory platforms. Journal of Magnetism and Magnetic Materials, 655 https://doi.org/10.1016/j.jmmm.2026.174334
