Propagating Spin Wave in Perpendicularly Magnetized TmIG/MgO/TmIG Trilayer for Magnonic Band‐Stop Filters

Magnonic devices, which utilize the spin angular momentum for information and energy transport, are key components for future computational architectures and information processing. Here, the propagating spin waves in perpendicularly magnetized TmIG/MgO/TmIG trilayer are investigated. When an external magnetic field is applied in the film plane and perpendicular to the wave vector, a frequency gap originating from the magnon–magnon coupling effect is found in the frequency dispersion relations. This feature can be exploited to develop a new type of magnonic device, such as magnonic band‐stop filter (BSF). A significant amplitude nonreciprocity is also observed in the transmission parameters, which depends on the magnetic field. Furthermore, the frequency gap vanishes when the magnetic field is applied parallel to the wave vector. It enables the design of a novel switchable magnonic BSF device. This work paves the way for its application as the next‐generation magnonic devices.