THE EFFECTS OF A LARGE OSCILLATING FIELD IN MAGNETIC RESONANCE; A STUDY BY LOW FREQUENCY DOUBLE ELECTRON MUON RESONANCE

There has been a considerable amount of investigation, both theoretical and experimental, of how spin systems behave in magnetic resonance when the applied dc field and the rf oscillating field have comparable amplitudes. A technique called Double Electron Muon Resonance has recently been applied to fused quartz at low frequency enabling us to see directly how the spin precesses in perpendicular dc and rf magnetic fields of comparable strength. The precessional frequency spectra are in excellent agreement with predictions by numerical integration of the equations describing spin precession. Among the effects observed have been harmonic responses, Bloch-Siegert shifts and multi-quantum transitions