Acoustic resonances of relaxation nature in CsI single crystals in the temperature range 2–20 K

Acoustic relaxations in CsI single crystals are investigated in the temperature range 2–20 K at frequencies (1–7) × 105 Hz. The absorption peak found earlier at temperatures 3–5 K, which is caused by preliminary plastic deformation at room temperature, is studied in detail. A new relaxation resonance that corresponds to a thermally activated process with the activation energy U ≈ (6.1–8.9) × 10−3 eV and the attempt frequency ν0 ≈ 2 × 109 to 8 × 1010 s−1 is revealed in the temperature interval 8–10 K.