Creation of uni-directional spin-wave emitters by utilizing interfacial Dzyaloshinskii-Moriya interaction

TL;DR

This paper analytically and numerically investigates how interfacial Dzyaloshinskii-Moriya interaction enables uni-directional spin-wave emission in ultra-thin ferromagnetic films, with potential applications in magnonic devices.

Contribution

It extends the analytical model of spin waves to include interfacial Dzyaloshinskii-Moriya interaction and demonstrates uni-directional emission in NiFe/Pt systems.

Findings

Achieved uni-directional spin-wave emission using Dzyaloshinskii-Moriya interaction.

Predicted optimal conditions for non-reciprocal emission with analytical formalism.

Compatible device sizes with current excitation and detection technologies.

Abstract

We present an analytic and numerical study of the creation of an uni-directional spin-wave emission in ultra-thin ferromagnetic films sandwiched in an asymmetric layer stack. For this we extend the analytical description of spin waves in spin-wave waveguides by the incorporation of the influence of the interfacial Dzyaloshinskii-Moriya interaction on the spin-wave propagation. By exploring the model system Ni$_{81}$Fe$_{19}$/Pt we show that it is possible to achieve an uni-directional spin-wave emission by combining wave-vector selective excitation sources with the frequency splitting which arises from interfacial Dzyaloshinskii-Moriya interaction. Hereby we focus on device feature sizes and spin-wave wavelengths compatible with state-of-the art excitation and detection schemes. We demonstrate that the optimum operation conditions for the non-reciprocal emission can be predicted using the presented analytical formalism