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Ionic Thermal Currents under Uniaxial Stress A New Method to Determine Electric and Elastic Dipole Properties
Author(s) -
Siu Li M.,
De Souza M.,
Kapphan S. E.
Publication year - 1982
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2221120240
Subject(s) - dipole , polarization (electrochemistry) , electric field , ionic bonding , perpendicular , condensed matter physics , dielectric , materials science , stress (linguistics) , orientation (vector space) , optics , molecular physics , chemistry , physics , ion , geometry , optoelectronics , mathematics , philosophy , linguistics , quantum mechanics , organic chemistry
The method of thermally stimulated depolarization (ITC) is expanded to allow the determination of elastic dipole properties. During sample polarization by the electric field a uniaxial stress is applied simultaneously (mostly parallel to it for practical reasons). Depending on the shape of the elastic dipole associated with the reorienting electric dipole, the total polarization will be either enhanced or reduced by the elastic dipoles being turned either parallel or perpendicular to the stress direction. The change of polarization (i.e. integrated ITC signal) for stress applied in several crystalline directions, yields additional information about the equilibrium orientation and stress splitting coefficients of the dipoles. This novel procedure is tested with a dipolar system known to exhibit a well defined ITC peak at about 25 K, off‐center Ag + in RbI. The results for the first time reveal clearly the elongated ellipsoidal (cigar‐shaped) form of the elastic distortion around this dipolar center. The question of equilibrium orientation, however, must remain open since both, a <111> and a restricted <110> (90° transitions only) off‐center model, suggested in recent elasto‐optic work by Lüty et al., allow a good fit of the available experimental data.