The attenuation of ultrasound by electrons in aluminium

Abstract

The attenuation of transverse and longitudinal ultrasonic waves has been studied as a function of magnetic field strength in aluminium single crystals at liquid helium temperatures. The conventional magnetoacoustic configuration with H ⊥q and with longitudinal waves has been reported in some detail elsewhere. The effect with transverse waves in this configuration is shown here to be less pronounced. Most emphasis is given to the resonant interaction between the electrons and the sound wave observed for H | q when large peaks are observed in the attenuation. The theory is presented and reasonable quantitative agreement found with longitudinal waves. The rotation of the plane of polarization of the shear waves has been investigated and may explain the poor agreement for shear waves.