Tunneling studies in Bi/sub 2/Sr/sub 2/CaCu/sub 2/O/sub 8+x/

Author

Cucolo, A.M. ; Di Leo, R. ; Nigro, A. ; Razavi, F.S.

Author_Institution

Dipartimento di Fisica, Salerno Univ., Baronissi, Italy

Volume

3

Issue

1

fYear

1993

fDate

3/1/1993 12:00:00 AM

Firstpage

1540

Lastpage

1542

Abstract

Planar tunnel junctions have been realized on liquid-etched Bi/sub 2/Sr/sub 2/CaCu/sub 2/O/sub 8+x/ (BSCCO) single crystals with natural barriers and Pb, Pb-Bi, Au counterelectrodes. At T=4.2 K and I-V characteristics of these junctions often show multiple switches that disappear at the T/sub c/ of the BSCCO compound. The dV/dI vs. V curves show gaplike structures at about +or-22 mV and second features at about +or-40 mV. These are very similar to the double structure observed in YBa/sub 2/Cu/sub 3/O/sub 7/ (YBCO) junctions. The background resistance above the gaplike features is flat in the majority of the junctions, while about 20% of the junctions show decreasing resistance with bias. For Pb and PbBi counterelectrodes, negligible leakage currents at low temperatures indicate good quality tunnel barriers, continuous and pin-hole free. The phonon structures of these materials indicate a single-step tunneling process. The behavior of the zero-bias resistance dip observed in some junctions is discussed.<>

Keywords

bismuth compounds; calcium compounds; high-temperature superconductors; strontium compounds; superconductive tunnelling; 4.2 K; Au counterelectrodes; Bi/sub 2/Sr/sub 2/CaCu/sub 2/O/sub 8+x/; HTSC; I-V characteristics; Pb counterelectrode; PbBi counterelectrode; background resistance; bias; gaplike structures; good quality tunnel barriers; leakage currents; liquid etched single crystals; low temperatures; multiple switches; natural barriers; phonon structures; planar tunnel junctions; single-step tunneling process; zero-bias resistance dip; Bismuth compounds; Crystals; Gold; Leakage current; Phonons; Strontium; Switches; Temperature; Tunneling; Yttrium barium copper oxide;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/77.233373

Filename

233373