Large surface acoustic wave nonreciprocity in synthetic antiferromagnets

We have studied the transmission of surface acoustic waves (SAWs) in ferromagnetic/non-magnetic/ferromagnetic tryilayers. The SAW scattering matrix is studied for devices with various non-magnetic spacer thickness, which defines the strength of the interlayer exchange coupling. We find the SAW transmission amplitude depends on its propagation direction when the two ferromagnetic layers are coupled antiferromagnetically. The degree of such SAW nonreciprocity increases with increasing exchange coupling strength and reaches 37 dB mm(-1) for a device with the thinnest spacer layer. These results show the potential of interlayer exchange coupled synthetic antiferromagnets for viable acoustic nonreciprocal transmission devices, such as circulators and isolators.

Automated summary

In this study, the transmission of surface acoustic waves (SAWs) in ferromagnetic/non-magnetic/ferromagnetic trilayers was investigated. It was found that the SAW transmission amplitude depends on its propagation direction when the two ferromagnetic layers are coupled antiferromagnetically. The degree of SAW nonreciprocity increases with increasing exchange coupling strength and reaches 37 dB mm(-1) for a device with the thinnest spacer layer. These findings demonstrate the potential of interlayer exchange coupled synthetic antiferromagnets for acoustic nonreciprocal transmission devices.