Collective Dynamics of Coexisting Spin Textures

Advances in controlling electron correlations in transition metal dichalcogenides have opened a new frontier of many-body physics in two dimensions. A field where these materials have yet to make a deep impact is antiferromagnetic spintronics—a relatively new research direction promising technologies with fast switching times, insensitivity to magnetic perturbations and reduced cross-talk. The theory behind the electrical switching of antiferromagnets is premised on the existence of a well-defined broken symmetry state that can be rotated to encode information. A spin glass is in many ways the antithesis of this state, characterized by an ergodic landscape of nearly degenerate magnetic configurations, freezing into its final distribution in a manner that is seemingly bereft of information.

In this talk, I will show that the coexistence of spin glass and antiferromagnetic order allows a novel mechanism to facilitate the switching of the intercalated transition metal dichalcogenide Fe_1/3±δNbS₂, which is rooted in the electrically stimulated collective winding of the spin glass. We find that remarkably low current densities of the order of 10⁴ A/cm⁻² can reorient the magnetic order in a single pulse activation. The local texture of the spin glass opens an anisotropic channel of interaction that can be used to rotate the equilibrium spin-orientation of the antiferromagnetic state. Moreover, I will present the first experimental observation of the predicted spin glass collective modes, known as Halperin-Saslow spin waves. The use of a spin glass’ collective dynamics to electrically manipulate antiferromagnetic spin textures has never been applied before, opening the field of antiferromagnetic spintronics to many more material platforms with complex magnetic textures.

link to the seminar