Sensitivity Enhancement by the Use of Acoustic Resonators in cw Ultrasonic Spectroscopy

Abstract

The role of an acoustic resonator in the study of cw acoustic magnetic resonance (AMR) effects is discussed. From the expression for the frequency response of a resonator consisting of an isolated sample, one can calculate absorption and dispersion sensitivities and determine the conditions under which a pure absorption or pure dispersion AMR signal may be observed. The calculation is extended to the case of a sample and transducer. The primary effect of the transducer is to shift the frequency of the isolated sample mechanical resonance without materially altering the mechanical resonance lineshape or associated AMR sensitivities.