DIELECTRIC STUDIES OF CN- DIPOLAR REORIENTATION AND ORDER DISORDER BEHAVIOR .1. PURE ALKALI-CYANIDE CRYSTALS/

The dielectric constant and dielectric loss of pure NaCN, KCN, RbCN, a nd CsCN crystals has been comprehensively studied as a function of tem perature. Besides dielectric measurements with a capacitance bridge in the 10(0) to 10(5) Hz regime, thermally stimulated depolarization cur rent (TSDC) techniques have been used for the first time in these syst ems to obtain information about the reorientation and ordering behavio r of CN- ions at lowest temperatures and relaxation rates. The extende d dipolar reorientation data are analyzed, using either Cole-Cole or H avriliak-Negami distributions of relaxation times with temperature-dep endent 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 relatio n to CN- electric-dipole ordering in these systems.