Nonreciprocity engineering in magnetostatic spin waves

• The amplitude of surface spin waves depends on their direction of propagation.
• We study nonreciprocal propagation of spin waves using micromagnetic simulations.
• The sense of rotation of magnetization has no correlation with the nonreciprocity.
• Nonreciprocity parameters are extracted for NiFe, CoFeAl, YIG, and GaMnAs.
• A device geometry is proposed, so nonreciprocity can be tuned to a large value.

Magnetostatic surface spin waves (MSSW) excited from a coplanar waveguide antenna travel in different directions with different amplitudes. This effect, called nonreciprocity of MSSW, has been investigated by micromagnetic simulations. The ratio of amplitude of two counter propagating spin waves, the nonreciprocity parameter κ, is obtained for different ferromagnetic materials, such as NiFe (Py), CoFeAl, yttrium iron garnet (YIG), and GaMnAs. A device schematic has been proposed in which κ can be tuned to a large value by varying simple geometrical parameters of the device.