Antiferromagnetic switching driven by the collective dynamics of a coexisting spin glass

Abstract

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, choosing to freeze into a distribution of these in a manner that is seemingly bereft of information. Here, we show that the coexistence of spin glass and antiferromagnetic order allows a novel mechanism to facilitate the switching of the antiferromagnet Fe1/3 + δNbS2, rooted in the electrically stimulated collective winding of the spin glass. The local texture of the spin glass opens an anisotropic channel of interaction that can be used to rotate the equilibrium orientation of the antiferromagnetic state. Manipulating antiferromagnetic spin textures using a spin glass’ collective dynamics opens the field of antiferromagnetic spintronics to new material platforms with complex magnetic textures.

Origins of anisotropic transport in the electrically switchable antiferromagnet Fe1/3NbS2

“…agrees with the experimental data in Ref. [38] for Fe intercalations likely corresponding to a-stripe and a-zigzag order.…”

“…Further studies are required to understand the origins of the current-domain coupling which leads to domains parallel to the current pulse being disfavored and whether this is consistent with the spin-glass-mediated spin-orbit torque mechanism proposed in Ref. [38].…”

“…( 3), additional deviations from experimental results may come from our use of the pristine x = 1 3 Fe concentration in all PBE+U calculations, as the recent transport and switching experiments [15,38] were performed on Fe x NbS 2 samples with a range of Fe concentrations x ∼ 0.31-0.35. Although NMR data suggest that a spin-glass coexists with the AFM order above and below x = 1 3 and may well be the underlying mechanism for the efficient switching of the ordered magnetic domains [38], we expect that the electronic structure and transport anisotropy of the stripe and zigzag phases, which we focus on in this paper, will not differ significantly between slightly off-stoichiometry structures and the x = 1 3 structure we use in our DFT calculations. Moreover, the NMR measurements, as well as contemporary neutron experiments [33], find evidence of a slight in-plane magnetic moment, in contrast to the earlier neutron studies [14,31].…”

“…4(a) we show the a-b plane of the Fe 1/3 NbS 2 crystal overlaid with the directions of applied currents and measured resistances for the experiments in Refs. [15,38]. In these experiments, DC pulses, J write 1 and J write 2 , were applied in succession along the −k y /[1 20] and k x /[100] crystallographic directions.…”

“…along J probe , are shown in Ref. [38] to be ∼2.5% and ∼1.3% (when normalized to the same DC pulse current density) for Fe intercalations corresponding to x = 0.31 and x = 0.35, respectively; the smaller intercalation was used in Ref. [15] as well.…”