PHONON AND PHOTON PARAMAGNETIC-RESPONSE LINE SHAPES IN RUBY

Acoustic-paramagnetic-resonance (APR) and electron-paramagnetic-resonance (EPR) line shapes have been measured in ruby for various Cr3+ concentrations. The second-moment theory of Pryce and Stevens is shown to be applicable to APR as well as EPR, predicting the same second moments Δν2 for both APR and EPR transitions. Experimentally, the APR and EPR line shapes are indeed identical for the same transition; however, the theory predicts a larger Δν2 than measured, because the larger Cr-Cr interactions do not appear in the observed line. A qualitative calculation of Δν2 from the known interactions supports this conclusion. © 1969 The American Physical Society.