Atomistic approaches on 2D magnetic materials

Thus, the suitability of the Ising model can be assessed. The atomistic spin model shows that the Ising model overestimates the T_C, and we show that by using a modified Heisenberg model, a value of T_C much closer to experiment can be calculated. Using this model and our calculated exchange parameters, the spin dynamics in monolayer CrI₃ can be examined with the Landau-Lifshitz-Gilbert equation.

Spins in monolayer CrI₃ appear to fluctuate in zero-field cooling simulations, seemingly as a result of the system’s high anisotropy. Zero-field cooling simulations are also performed on bulk CrI₃ revealing a multi-step transition in the material. To consider CrI₃’s potential in domain wall motion based technology, simulations of a moving domain wall are carried out on a short section of nanowire to assess domain wall motion under applied field and with the use of a spin-transfer torque, applied current.

High velocities of 1020 m/s are reached under applied current. At this point the material undergoes a Walker breakdown collapse of the domain wall, so the limits of CrI₃ domain wall motion capabilities are shown.