Inhomogeneous electron paramagnetic resonance line broadening in ruby

The angular variations of the electron paramagnetic resonance linewidths of the Δ M = 1 transitions at 35 GHz have been studied in rubies grown by the vapour phase, Verneuil and Czochralski processes and having chromium concentrations in the range 0.015 to 0.20 at.%. Using a strain and mosaic model, parameters characterizing the strain at the Cr 3+ sites and the axial misorientation have been derived by a least-squares analysis. The spread in zero-field splitting is typically about 5 × 10 -4 cm -1 , giving Δ(2 D )/2 D similar, equals 10 -3 . The values of the strain components e xx , e zz and e xz lie in the range 10 -4 to 2 × 10 -2 and appear to be growth dependent.