Electric field effect in electron-nuclear double resonance of Cr3+ ions in ruby

The linear electric field effect in electron-nuclear double resonance spectra of the proper nuclei of the impurity ions (Cr53)3+ and ''distant'' Al27 nuclei in ruby is investigated in an external stationary electric field on intensity up to 800 kV/cm at T=4,2K. The electric field-induced variation of the hyperfine interaction parameter of the impurity ion and of the electric field gradients at the Cr53 and Al27 nuclei are determined by measuring the spectral line splitting. It is assumed on basis of the data obtained that for both types of nuclei the mechanisms responsible for the variation of the electric field gradient are the same. The orbital contribution and the contribution of the ion core polarization to the variation of the hyperfine interaction parameter are estimated. The shift of the electron g-factor is also estimated