  Low-energy magnonic logic circuits are an actively developing field of modern
magnetism. The potential benefits of magnonics for data processing are vitally
dependent on units based on non-reciprocal propagation of spin waves in analogy
to semiconductor diodes and transistors in electronics. In this article, we
suggest the approach to realize non-reciprocal propagation of spin waves in a
ferromagnetic metallic waveguide by exciting them with femtosecond laser pulse.
Using micromagnetic modeling, we show that the combination of an external
magnetic field and the position of the excitation laser spot across the
waveguide leads to unidirectional propagation of the excited spin-wave packet.
The results are crucial for the design of hybrid magnonic-photonic circuits in
future generations of data processing devices.
