Petchenko G. Acoustic investigation of dynamic dislocation effects in KBr crystals

Object - abbove-barrier dislocation movement drag in KBr monocrystals; aim - the study of phonon-dislocation interaction and the interaction of dislocation with the points of pinning in KBr monocrystals; methods - pulse echo-method of high-frequency (Mc) range, selective etching method, method of active loading, optical method; results, novelty - it was at first time found that in the deformation range 0,23 - 1,5% the drag constant doesn't depend on the density of moving dislocations and is governed by dissipative processes going on in the phonon subsystem of the crystal; it was at first time established that in the temperature interval under investigation (77 - 300 K) the phonon drag of dislocations is determined by the superposition of the mechanisms of phonon wind and of the "slow" phonons relaxation, the inpact of phonon wind on the resulting drag value being the prevailing one; the process of the dislocations tearing off the pinning points in KBr at the initial stage of crystal deformation (in thequasi-elastic region) was at first time analized by means of thermoactivation method; the activation energy and the activation volume of the given process were determined and on their basisi the force law of the dislocation interactions with the contamination impurity pinning points was formulated; field of implementation - state solid physics, acoustical electronics