Dissipative Spin-wave Diode and Nonreciprocal Magnonic Amplifier

TL;DR

This paper introduces a dissipative spin-wave diode and nonreciprocal magnonic amplifier using engineered dissipation and magnetic interactions, with potential applications in spintronics and non-Hermitian physics.

Contribution

It presents a novel design for a dissipative spin-wave diode and amplifier leveraging nonreciprocal dissipation and coherent interactions, connecting spin-wave physics with non-Hermitian topology.

Findings

Dissipative coupling enables nonreciprocal spin-wave propagation.

Balanced Dzyaloshinskii-Moriya interaction determines diode polarity.

Cascading magnetic layers enhances amplifier gain.

Abstract

We propose an experimentally feasible dissipative spin-wave diode comprising two magnetic layers coupled via a non-magnetic spacer. We theoretically demonstrate that the spacer mediates not only coherent interactions but also dissipative coupling. Interestingly, an appropriately engineered dissipation engenders a nonreciprocal device response, facilitating the realization of a spin-wave diode. This diode permits wave propagation in one direction alone, given that the coherent Dzyaloshinskii- Moriya (DM) interaction is balanced with the dissipative coupling. The polarity of the diode is determined by the sign of the DM interaction. Furthermore, we show that when the magnetic layers undergo incoherent pumping, the device operates as a unidirectional spin-wave amplifier. The amplifier gain is augmented by cascading multiple magnetic bilayers. By extending our model to a one-dimensional ring structure, we establish a connection between the physics of spin-wave amplification and non-Hermitian topology. Our proposal opens up a new avenue for harnessing inherent dissipation in spintronic applications.