Electrical Detection of Short-Wavelength Nonreciprocal Magnons in Magnetic Thin Film Device*

Magnons possess nonreciprocity with multiply mechanisms and can reach ultra-small wavelength down to nanometer scale at microwave frequency excitations, they can be utilized for developing miniaturized and chip-embedded microwave isolation components for advanced information processing. Up to now, high performance of magnon isolation in magnetic thin-film devices is still demanding for practical applications.

 

In this work, we experimentally realized broad-band nonreciprocal magnon propagation in a 100-nm yttrium iron garnet (YIG) thin film transducer. With nanofabrication of nanoscale (down to 200 nm) microwave antennas on fabricated YIG thin film (100 nm) device, we successfully demonstrate electrical detection of nonreciprocal short-wavelength (800 nm) spin wave propagation with 30 dB isolation, which is due to chirality selection of the Oersted field from the GSG antenna. Time-domain transmission analysis show that the device can support narrow pulse width down to 6 ns with time delay of more than 100 ns achieved in a short distance of 20 um. Furthermore, we reveal the appearance of two extra magnon bands when the geometry or the YIG thickness changes, leading to the reduction of magnon nonreciprocity. Our result provide a viable platform for chip-embedded microwave isolator for quantum information processing such as qubit noise reduction and entanglement purification.