BE-11 Strain Effects on Fluctuation Properties of Noncollinear Antiferromagnets for Probabilistic Computing Applications

Noncollinear antiferromagnetic materials with D019 crystal symmetry (e.g., Mn3X; X=Sn, Ge, etc.) exhibit intriguing properties, positioning them as promising candidates for probabilistic computing. Despite being antiferromagnetic, the unique crystal symmetries in these systems allow phenomena such as tunneling magnetoresistance and the anomalous Hall effect, making them amenable to electrical readout techniques. Additionally, the competing magnetic interactions inherent in these systems give rise to an effective low-barrier system, a crucial element for accelerating existing probabilistic computing hardware. However, real-world samples of noncollinear antiferromagnets have not yet been developed into functional generators of randomness. This is speculated to be due to strain effects, which predominantly influence the material's pristine parameters [1, 2], thereby severely affecting their fluctuation properties. In this work, by combining density functional theory and micromagnetic simulations, we quantify the effect of epitaxial strain on the lattices of noncollinear antiferromagnets to predict their fluctuation properties. We find that strains typical of those due to substrates used to date increase the barrier high enough to drastically slow down the switching rate. These findings will not only help us design noncollinear antiferromagnets that are less susceptible to strain effects, leading to better p-bit candidates, but also develop novel methods for controlling and manipulating magnetism within this promising material platform.References: [1] Higo, Tomoya, et al. Nature 607 (2022) 474 [2] Z. He, L. Liu, J. Appl. Phys. 135 (2024) 093902