Origin of Periodic Fluctuations with Temperature of Ultrasonic Attenuation in zinC, Aluminium, and Iron

Abstract

The ultrasonic attenuation-temperature curves for zinc, aluminium, and iron are found to comprise a periodic fluctuation of the attenuation with temperature as measurcd a t 2, 4, and 8 MHz.This fluctuation is superposed on the well-known types of ultrasonic damping in metals. The periodicity of such fluctuations is explained in terms of successive thermal levels of atomic vibrations. This approach affords successfully the visualization of the responsible pair of levels which effectively predominates along a certain interval of temperature and furnishes a lossive two-state model. The successive models are also supported by a previous work on nickel.