Interfacial Dzialoshinskii-Moriya interaction induced nonreciprocity of spin waves in magnonic waveguides

The nonreciprocal propagation of spin waves in magnonic waveguides is investigated using micromagnetic simulations. The magnonic waveguides are in the form of ferromagnet/normal metal bilayers inducing interfacial Dzialoshinskii-Moriya interaction (DMI). The presence of the interfacial DMI is demonstrated to induce the nonreciprocity of spin waves, i.e. different frequencies, amplitudes, and mode profiles for propagating in opposite directions. In addition, our simulation reveals the existence of unidirectional propagation of spin waves which travel only along one direction, either forward or backward. Our results therefore show the potential of using magnonic waveguides with the presence of DMI as building blocks for a new class of compact nonreciprocal magnonic devices including one-way waveguides (isolators) and circulators.