Electron Tunneling Into Superconducting Lead Subjected to Hydrostatic Pressure PDF Download

Author: William J. Keeler
Publisher:
ISBN:
Category : Superconductors
Languages : en
Pages : 0

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Book Description
Studies of superconductors as a function of pressure have, until now, been concerned mainly with the bulk properties of the metals. A study of the shift of some of the microscopic properties of strong-coupling Pb with pressure has been undertaken and this thesis reports the results of this pressure study. The method of investigation used was the electron tunneling technique, where the pressure production was achieved by suspending the samples in a solid helium bath. The energy gap and phonon spectrum of Pb as reflected in the junction conductance curves were studied as a function of pressure for the first time. The average value of dT /dP from many different junctions is in agreement with published results for bulk Pb. Shifts in the predominant transverse and longitudinal phonon groups were observed. These shifts occur in the dispersive region of the two main phonon branches. Gruneisen q's of 7 ( 0 ) = 2 0 52 and y(co) = 3.32 were obtained for the phonon peak- regions., and these can be favourable compared with results from thermal expansion work. The "recombination effect" was studied and found to be smaller than predicted, and perhaps absent altogether.