Iacocca group published in npj Computational Materials

The pseudospectral Landau-Lifshitz (PS-LL) equation was introduced by Iacocca’s group [Phys. Rev. B 109, L180404 (2024)] as a numerical means to resolve the atomic to continuum transition of magnetization dynamics in a unified manner. The method relies on a convolution kernel that captures the correct exchange interaction. Because the kernel is defined in Fourier space, it is grid-independent and long-range.

Any kernel can be defined. For this reason, Dr. Alison Roxburgh, a former graduate student in Iacocca’s group, investigated the application of the PS-LL model for magnonics, i.e., in the case of long waves. In that case, the nonlocal dipole field dominates the intersite interactions, leading to backward volume waves and surface waves in the thin film’s plane. Computationally, resolving these waves requires the computation of dipole fields via a convolution tensor.

In the work published in npj Computational Materials, the authors use a known analytical solution for magnetostatic waves to define a convolution magneto-dipolar kernel applicable to the 2D PS-LL model, developed by Dr Matthew Copus [Nature Communications 15, 10742 (2024)]. The kernel reproduces the correct magnon dispersion relation in 2D and is demonstrated to reproduce known results such as wave excitation with a microwave field, caustics, and magnon scattering. Use of the magneto-dipolar kernel reduced the number of fast Fourier calculations per integration step, achieving a 2x speed-up.

Details can be found in the article npj Computational Materials 11, 369 (2025).