High sensitivity RF detection of domain wall resonance in magnetic garnet films

A novel technique that improves both the coupling of the domain wall with the RF excitation field and the signal/noise ratio of the detected signal associated with the wall oscillations is reported. Measurements were made on full wafer garnets in a wideband resonance spectrometer with a nonresonant microstrip transmission excitation line. The problem of the standing wave ratio (SWR) change with RF frequency inherent in the reflection-type spectrometer is eliminated by using a subtraction mode of the digital oscilloscope. Large signals from normal and flexural wall modes are easily detected, and fine structures associated with magnetoelastic coupling are observed in [111]- and [110]-oriented garnet films with different magnetic parameters.>