Dielectric studies of CN^- dipolar reorientation and order/disorder behavior: I. Pure alkali-cyanide crystals

The dielectric constant and dielectric loss of pure NaCN, KCN, RbCN, and CsCN crystals has been comprehensively studied as a function of temperature. Besides dielectric measurements with a capacitance bridge in the 10⁰ to 10⁵ Hz regime, thermally stimulated depolarization current (TSDC) techniques have been used for the first time in these systems to obtain information about the reorientation and ordering behavior of CN^- ions at lowest temperatures and relaxation rates. The extended dipolar reorientation data are analyzed, using either Cole-Cole or Havriliak-Negami distributions of relaxation times with temperature-dependent parameters. A phenomenological model is proposed, based on the assumed existence of a distribution of random bias electric fields to explain the observed behavior of the dipolar susceptibility in relation to CN^- electric-dipole ordering in these systems.