Low Temperature Physics: 33, 197 (2007); https://doi.org/10.1063/1.2719955 (5 pages)
Fizika Nizkikh Temperatur: Volume 33, Number 2-3 (February 2007), p. 269-275 ( to contents , go back )
Relaxation time, dynamic, relaxed, and unrelaxed elastic moduli in ZnSe:Cr investigated with ultrasonic waves
The state professional - pedagogical university Street. Machine engineers, 11, Ekaterinburg, 620012, Russia
A.T. Lonchakov, V.I. Sokolov, and I.V. Zhevstovskikh
Institute of Metal Physics RAS, Ekaterinburg 620041, Russia
Received August 7, 2006
The temperature dependences of absorption and phase velocity of ultrasound propagating along the  axis were investigated in the ZnSe crystal doped with Cr2+ ions at frequencies 32-158 MHz. It is found that the absorption peak and phase velocity anomalies, observed in the interval 10-20 K, are of relaxation origin. The temperature dependences of relaxation time, relaxed (isothermal), and unrelaxed (adiabatic) elastic modulus Cl = 1/2(C11 +C12+2C44) are reconstructed. Oscillations of amplitude and phase of the signal were found at the frequency 32 MHz. An interpretation of the phenomenon is suggested.
PACS: 43.35.+d Ultrasonics, quantum acoustics and physical effects of sound;
Key words: elastic moduli, ultrasound, semiconductors, impurities.