Propagating backward-volume spin waves in epitaxial Fe films

Abstract

The propagation characteristics of backward-volume magnetostatic spin-waves in epitaxial Fe(001) films were studied by frequency-domain and time-domain spin-wave propagation spectroscopies using a vector network analyser. Due to the combination of cubic-magnetocrystalline anisotropy and anisotropic spin-wave dispersion, the backward-volume spin-wave exhibited a complicated packet propagation. For the hard-axis propagation, the group velocity of the spin wave was greatly enhanced at low external magnetic fields and propagation occurred even under no magnetic field. By analysing within a theoretical model and micromagnetic simulations, these transmission character of the backward-volume magnetostatic spin-waves in an epitaxial iron film was well reproduced. The observed characteristics are essential information to promote two-dimensional magnonic devices utilizing cubic-anisotropic materials.