  The efficient excitation of spin waves is a key challenge in the realization
of magnonic devices. We demonstrate the current-driven generation of spin waves
in antiferromagnetically coupled magnetic vortices. We employ time-resolved
scanning transmission X-ray microscopy (TR-STXM) to directly image the emission
of spin waves upon the application of an alternating current flowing directly
through the magnetic stack. Micromagnetic simulations allow us to identify the
origin of the excitation to be the current-driven Oersted field, which in the
present system proves to be orders of magnitude more efficient than the
commonly used excitation via stripline antennas. Our numerical studies also
reveal that the spin-transfer torque can lead to the emission of spin waves as
well, yet only at much higher current amplitudes. By using magnetostrictive
materials, we futhermore demonstrate that the direction of the magnon
propagation can be steered by increasing the excitation amplitude, which
modifies the underlying magnetization profile through an additional anisotropy
in the magnetic layers. The demonstrated methods allow for the efficient and
tunable excitation of spin waves, marking a significant advance in the
generation and control of spin waves in magnonic devices.
