Low-Temperature Anomalies in Pure Niobium Studied Ultrasonically
Elsewhere in these conference proceedings we report results of magneto-acoustic studies in niobium. In the present paper we discuss some curious magneticfield-independent effects which we have encountered in the normal and superconducting states of high-purity Nb. While we believe that some of these are connected, it will prove convenient to introduce them separately under the following “labels”: (I) The effect of high ql on the reported deviation from BCS predictions1 for case I absorption in superconducting niobium; (II) the question of electromagnetic coupling between transverse phonons and excited quasiparticles (for H = 0), examined in the transverse wave acoustic attenuation near Tc; (III) the discovery of a low-temperature maximum in the normal-state electronic attenuation in high-purity niobium.
KeywordsUltrasonic Attenuation Electromagnetic Coupling Transverse Phonon Attenuation Ratio Pure Niobium
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