Ultrasonic Attenuation in KCl:OH− with High OH Concentration
The low temperature properties of KC1 containing OH impurities have been studied in detail and the microscopic model is well known. The hydroxyl ion enters in substitution for Cl− and has six equilibrium orientations among which it performs motions at low temperatures . Besides its electric dipole moment, the substitutional OH− ion, because of distortions in the host lattice, induces the existence of an “elastic dipole” which may interact with an applied stress field . Ultrasonic measurements performed at low temperatures where the thermal energy is comparable with the energy of dipolar interactions among OH defects are presented here.