Spin-Wave Diode and Circulator Based on Unidirectional Coupling

In magnonics, a fast-growing branch of wave physics characterized by low energy consumption, it ishighly desirable to create circuit elements useful for wave computing. However, it is crucial to reach thenanoscale so as to be competitive with the electronics, which vastly dominates in computing devices.Here, based on numerical simulations, we demonstrate the functionality of the spin-wave diode and thecirculator to steer and manipulate spin waves over a wide range of frequency in the GHz regime. Theytake advantage of the unidirectional magnetostatic coupling induced by the interfacial Dzyaloshinskii-Moriya interaction, allowing the transfer of the spin wave between thin ferromagnetic layers in only onedirection of propagation. Using the multilayered structure consisting of Py and Co in direct contact withheavy metal, we obtain submicrometer-size nonreciprocal devices of high efficiency. Thus, our work contributesto the emerging branch of energy-efficient magnonic logic devices, giving rise to the possibilityof application as a signal-processing unit in the digital and analog nanoscaled spin-wave circuits.