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Proceedings Paper

Origin of fine structure in tunneling spectra of BiSrCaCuO films
Author(s): Vladimir M. Svistunov; Yu. F. Revenko; D. N. Afanassyev; V. D. Okunev
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Paper Abstract

Tunneling spectroscopy studies have been carried out on BSCCO textured films (2212 and 2223 phases) at T equals 4.2 K using the point junction technique with a silver or lead needle as an injector electrode. The tunneling spectra recorded in superconductive state have demonstrated the gap structures corresponding to S-I-S and S-I-N tunneling junctions. The energy gap peaks of the metaloxide correspond to the tunneling along ab plane in the CuO$0- 2) layer. The effect of the series resistance of the deteriorated surface layer which is responsible for the gap broadening in addition to that due to the finite lifetime of quasiparticles is discussed in connection with the determination of the energy gap. The tunneling spectra of Bi-2212 revealing the sharp gap peaks and a reproducible structure above the gap have been investigated in detail. The gap of Pb was also observed in the spectra of BSCCO-Pb junctions suggesting that a S-I-N junction has been formed between the needle and the normal surface of the film. Above the gap, some fine structure independent on magnetic field up to 0.5 T was observed. The most distinct feature was a pronounced dip at the energy of 70 meV which amplitude varied with junction resistance and bias polarity. This feature is consistent with the results of studies on single crystals. We assume this dip is due to the effects of layered structure of metaloxide, the interlayer pairing. The observed V-shaped conductance curve in sub-gap region is also consistent with this model. The remaining weak peculiarities we consider to be due to the electron-phonon interaction. The problem of Eliashberg function reconstruction from these data is discussed.

Paper Details

Date Published: 10 June 1996
PDF: 9 pages
Proc. SPIE 2696, Spectroscopic Studies of Superconductors, (10 June 1996); doi: 10.1117/12.241799
Show Author Affiliations
Vladimir M. Svistunov, A.A. Galkin Physico-Technical Institute (Ukraine)
Yu. F. Revenko, A.A. Galkin Physico-Technical Institute (Ukraine)
D. N. Afanassyev, A.A. Galkin Physico-Technical Institute (Ukraine)
V. D. Okunev, A.A. Galkin Physico-Technical Institute (Ukraine)

Published in SPIE Proceedings Vol. 2696:
Spectroscopic Studies of Superconductors
Ivan Bozovic; Dirk van der Marel, Editor(s)

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