Internal Friction in Deformed Germanium Single Crystals

The internal friction of germanium single crystals is investigated in the temperature range from 77 to 503°K at resonance frequencies of about 1200 Hz. Two relaxation peaks P_1 and P_2 with activation energies of (0.62±0.03) and (0.85±0.03) eV, respectively, are observed to develop in deformed crystals. The height of peak P_1 increases drastically upon deformation while it decreases gradually upon annealing. Peak P_1 is interpreted to be associated with the motion of geometrical kinks on dislocations. Peak P_2 develops only after a moderate plastic deformation followed by a subsequent annealing. It could be interpreted to be associated with the motion of dislocations in the surface region by means of single kink formation