Theoretical seminar | 27 April 2022

ITMO University
Effect of the demagnetizing field on the stability of topological solitons

The lifetime of topological solitons, such as magnetic skyrmions, is a key issue in the design of magnetic racetrack memory and logic gates. Different mechanisms are responsible for the stabilization of the skyrmions at different scales: nanoscale skyrmions are stabilized by the Dzyaloshinskii–Moriya interaction, but microscopic and 3D solitons are stabilized by the dipole-dipole interaction. The numerical methods developed to date have proved to be effective for predicting the lifetime of small solitons, but taking into account the dipolar interaction is a challenging task due its long-range nature. The locality of interactions can be restored if, instead of the dipolar interaction, the demagnetizing field is considered at the cost of adding new degrees of freedom. We propose an extension of the transition state theory for magnetic systems accounting for the demagnetizing field. This approach preserves the sparseness of the Hessian matrix of energy, which makes it possible to apply previously developed numerical methods to calculate the lifetime of magnetic states with millions of spins.

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