Magnetoacoustic oscillations in indium due to the frequency dispersion

Abstract

A detailed investigation of the recently disco vered magnetoacoustic oscillations of ellipticity has been undertaken in indium single crystals under the non-traditional mutual orientation of the magnetic field H and the ultrasound wave-vector q (close to H‖q). It has been found that oscillations appear in the field dependences of absorption and phase velocity of the circularly polarized ultrasonic waves, and also in those of ellipticity and the angle of rotation of the polarization piane. A description of the phenomenon observed has been given. The oscillations have been shown to be conditioned, unlike the Pippard geometrie oscillations, not only by spatial, but also by frequency dispersion. An analysis of the experimental data points to an electromagnetic nature of the oscillations discussed. Attention is drawn to opportunities to utilize the phenomena to determine the size of the cyclotron trajectory along the magnetic field and to recover the temperature dependence of the relaxation time for the effective electrons.