Magnetoacoustic Attenuation in Semimetals. II. Tilt Effect in Bismuth and Bismuth-Antimony Alloys

Abstract

The tilt effect in sound attenuation at low temperatures has been studied for bismuth to derive the relaxation time of the limiting point carriers. The comparison between the experimental data and a theory leads to a result that for most cases of orientations of the magnetic field and the sound wave vector the relaxation time is of the order of 1∼6×10⁻⁹ sec: the value is one order of magnitude longer than those from other classical transport phenomena. On the contrary to bismuth, the tilt effect is absent even in a very dilute alloy Bi_0.999Sb_0.001. This absence of the tilt effect is tentatively explained by assuming random diffractions of the sound wave propagation direction due to a spatial inhomogeneity of antimony concentration in the alloy.