Dipole-exchange spin waves in antiferromagnetic and altermagnetic thin films
Phys. Rev. B 114, 014427 – Published 29 July, 2026
DOI: https://doi.org/10.1103/wh56-mxp5
Abstract
We present a theoretical study of dipolar-exchange spin waves in antiferromagnetic and altermagnetic thin films using a multilayer model in which both sublattices coexist within the same layer. The calculated dispersion of pure dipolar spin waves agrees well with the established results for uniaxial antiferromagnets. By including exchange fields, we systematically analyze mode evolution, spatial profiles, and precession ellipticity, revealing how the interplay between exchange and dipolar interactions reshapes the spin-wave spectrum, including band crossings and mode hybridizations. Extending the framework to altermagnets with sublattice-dependent anisotropic exchange reveals an angle-dependent mode coupling: A hybridization gap opens for most propagation directions except at a specific angle, where the modes may remain degenerate due to the -wave altermagnetic symmetry. A comparison with a synthetic antiferromagnetic model further highlights the essential role of the model-dependent dipolar field. Our results provide a solid theoretical basis for interpreting and designing spin-wave experiments in antiferromagnetic, altermagnetic, and ferrimagnetic thin films.
