  The characteristics of spin waves in ferromagnetic waveguides with nonuniform
magnetization have been investigated for situations where the shape anisotropy
field of the waveguide is comparable to the external bias field. Spin-wave
generation was realized by the magnetoelastic effect by applying normal and
shear strain components, as well as by the Oersted field emitted by an
inductive antenna. The magnetoelastic excitation field has a nonuniform profile
over the width of the waveguide because of the nonuniform magnetization
orientation, whereas the Oersted field remains uniform. Using micromagnetic
simulations, we indicate that both types of excitation fields generate
quantised width modes with both odd and even mode numbers as well as tilted
phase fronts. We demonstrate that these effects originate from the average
magnetization orientation with respect to the main axes of the magnetic
waveguide. Furthermore, it is indicated that the excitation efficiency of the
second-order mode generally surpasses that of the first-order mode due to their
symmetry. The relative intensity of the excited modes can be controlled by the
strain state as well as by tuning the dimensions of the excitation area.
Finally, we demonstrate that the nonreciprocity of spin-wave radiation due to
the chirality of an Oersted field generated by an inductive antenna is absent
for magnetoelastic spin-wave excitation.
