Dielectric response ofN2−Arsolid solutions in the audio frequency range

Abstract

High sensitivity dielectric measurements are reported for ${\mathrm{N}}_{2}\ensuremath{-}\mathrm{Ar}$ solid mixtures for $49<x({\mathrm{N}}_{2})<100\mathrm{mol}%.$ The results show the onset of strong hysteresis effects for the temperature dependence of the dielectric constant on thermal cycling below 30 K. These onset temperatures are identified with transitions to a quadrupolar glass state. Samples cooled from high temperatures (above 50 K) in the presence of a small external ac electric field also show a characteristic field-cooled history dependence down to 50% dilution of ${\mathrm{N}}_{2}.$ The results presented are purely empirical, but qualitative estimates of the magnitude of the effects using a generalized fluctuation-dissipation argument are consistent with the observations.