Planar tunnel junctions on 90 K and 60 K YBCO single crystals. Superconducting and normal state properties

A. M. Cucolo, R. C. Dynes, J. M. Valles, L. F. Schneemeyer

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We have studied the tunneling characteristics of planar junctions made on YBCO single crystals with Tc=90 K and Tc=60 K. Natural barriers of good quality have been obtained on both compounds. In comparison with the 90 K phase, the superconducting conductance curves of the 60 K phase show gap-like structures reduced in amplitude and shifted towards higher energies. For the higher Tc material, a gap opening, at about 90 K, is observed. Normal state conductances, measured at T>Tc, are highly linear in voltage on both compounds and have steeper slopes on the 60 K phase. The slopes are quite insensitive to temperature variations, and do not depend on the junction resistances nor on the materials used as counterelectrodes.

Original languageEnglish
Pages (from-to)69-74
Number of pages6
JournalPhysica C: Superconductivity and its applications
Issue number1-3
StatePublished - 15 Aug 1991


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