  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.
