Conversion of magnetostatic spin waves propagating through a junction of magnonic waveguides

Wave channeling is an important problem for signal processing systems and communications within both optical and microwave frequency ranges [1-3]. In optics, the propagation path of a light can be controlled e.g. via the total internal reflection or in photonic crystal fibers. Thus, the simplest problem of wave channeling - turning a wave round a corner - is trivial in photonics, which is due to the isotropy of the optical dispersion. In magnonics [4], in contrast, the information carriers are spin waves, which have a strongly anisotropic dispersion. As a result of this, the magnonic group and phase velocities are non-collinear, while the relationship between them depends strongly on the orientation of the magnetization and the strength of the applied magnetic field. In principle, bends could be avoided in architectures in which magnonic waveguides form right angles at the junctions. However, the same anisotropy then poses another problem - that of conversion between the magnetostatic surface spin waves (MSSWs) and backward volume magnetostatic spin waves (BVMSWs), which have their wave vectors perpendicular and parallel to the direction of the magnetization, respectively.