Anisotropy of Superconducting Energy Gap in Aluminium Determined by Ultrasonic Method

概要

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The attenuation of 10 MHz ultrasound in aluminum has been measured bythe pulse reflection method at temperatures between 0.4 and 1.2 K. Three cylindri-cat single-crystal specimens of high purity and perfection, having 99.9999'3 ofpurity and low density of dislocations, were used and their crystallographicorientations were [1003, [1104 and [1114. The temperature dependence of attenua-tion in the superconducting state was analyzed on the basis of the BCS theory,and the apparent superconducting energy gap was determined for the above threesound propagation directions. By using these results, the energy gap anisotropyin the electronic A-space was derived. The gap value ranged between 3.56 and3.14 in units of (1/2)k?T.. The gap was largest forthe[100]direction,somewhatsmaller for the [1104 direction, and especially small for the [1114 direction. Theseconclusions were in agreement with existing experimental and theoretical results.
社団法人日本物理学会の論文
1985-09-15