Observation of a Collective Mode in Superconducting U<span class="aps-inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi mathvariant="normal">Be</mi></mrow><mrow><mn>13</mn></mrow></msub></mrow></math></span>

Brage Golding; D. J. Bishop; B. Batlogg; W. H. Haemmerle; Z. Fisk; J. L. Smith; H. R. Ott

doi:10.1103/PhysRevLett.55.2479

Observation of a Collective Mode in Superconducting U ${Be}_{13}$

Brage Golding, D. J. Bishop, B. Batlogg, W. H. Haemmerle, Z. Fisk, J. L. Smith, and H. R. Ott

Phys. Rev. Lett. 55, 2479 – Published 25 November 1985

Abstract

Sound propagation in the heavy-fermion superconductor U ${Be}_{13}$ is studied at frequencies from 0.9 to 2.4 GHz and temperatures from 0.01 to 100 K. A peak in the acoustic attenuation is observed below the superconducting transition of 0.9 K, instead of the rapid drop expected for a BCS superconductor. Absorption into a collective mode of a nonsinglet, anisotropic superconductor is proposed.