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Title:Propagation of zero sound in liquid He3
Author(s):Abel, William Russell
Doctoral Committee Chair(s):Wheatley, J.C.
Department / Program:Physics
Subject(s):sound propagation
zero sound
liquid He3
Curi-law magnetic susceptibility
Abstract:The propagation of sound in liquid He3 was observed at a pressure of 0.32 atm and at fre~quencies of 15.4 and 45.5 MHz down to a temperao 0 -3 0 . ture T* of 2m K (1m K = 10 K) on the temperature scale va11d for the Curie-law magnetic susceptibility of powdered cerium magnesium nitrate in the form of a right circular cylinder with diameter equal to height. The results of the measurements have been published by the author, A. C. Anderson, and J. C. Wheatley. * As the temperature was increased, the sound attenuation increased, went through a max.imum, and then decreased. At low temperatures, the attenuation was proportional to T~,(2 but independent of frequency, and at higher temperatures it was proportional to W 2/T*2, where w is the angular frequency of the sound. The temperature at which max.imum attenuation occurred was o 0 11.3m K for the frequency of 15.4 MHz and was 19.3m K for 45.5 MHz. The velocity of the sound was found to be relatively temperature independent at high and low temperatures but near the attenuation maximum the velocity changed by 3.5 ± 0.3 percent. The results of the measurements are predicted by the Landau theory of a Fermi liquid, the velocity change and the temperature dependence of the attenuation coefficient at low temperatures being explained by the propagation of a new mode of sound, called zero sound. The velocity change is in quantitative agreement with the theory. The attenuation of zero sound is about 35% larger than that predicted by theory, but could be explained by a shorter collision time between quasiparticles in the zero sound regime, The frequency and temperature dependence of the attenuation coefficient at higher temperatures are those predicted for ordinary hydrodynamic sound.
Issue Date:1966
Genre:Dissertation / Thesis
Rights Information:1966 William Russell Abel
Date Available in IDEALS:2011-05-20
Identifier in Online Catalog:6178871

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