Magnetoacoustic Phenomena in SrTiO3

Abstract

The effects of parabolic and nonparabolic band structures on the propagation of ultrasound in SrTiO3 in the presence of a dc magnetic field have been studied by using a quanium treatment which is valid at high frequencies and in strong magnetic fields. The major interaction between the ultrasound and conduction electrons is via deformation coupling. Results are shown that the absorption coefficient and sound velocity depend strongly on the sound frequency and longitudinal dc magnetic field. At the high field region, some oscillations in the absorption coefficient and sound velocity with the dc magnetic field occur at the high ultrasonic frequencies. These oscillations are interpreted as the so-called "giant quantum oscillations" which can be observed when the seperation between Landau levels is greater than their thermal broadenings in the region of high frequencies. It is also shown that some discontinuities in the absorption coefficient and change in sound velocity occur in the region of strong magnetic fields.