Observation of granularity in YNi{sub 2}B{sub 2}C superconductors containing normal impurity phases

Journal Article · Fri Sep 01 04:00:00 EDT 1995 · Physical Review, B: Condensed Matter

DOI:https://doi.org/10.1103/PhysRevB.52.6734· OSTI ID:115831

Bar-Sadeh, E; Felner, I; Asaf, U; Millo, O ^[1]

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1. Racah Institute of Physics, The Hebrew University, Jerusalem 91904 (Israel)

Cryogenic scanning tunneling microscopy is used to study the local electronic properties of intermetallic YNi{sub 2}B{sub 2}C superconductors. Samples which were prepared with Ni deficiency showed a sharp superconducting transition, onset around 15 K, while x-ray-diffraction measurements clearly indicated a presence of a nonsuperconducting YB{sub 2}C{sub 2} phase. Our scanning tunneling spectroscopy measurements on these samples show strong spatial variations of the tunneling conductance, consistent with granular materials. In particular, we observe reproducible transitions between normal regions to superconducting regions, having a gap parameter of 2.55{plus_minus}0.05 meV at 4.2 K, on length scales of 20 nm. In addition, the {ital I}-{ital V} characteristics often manifest single-electron tunneling effects, also typical of granular systems.

• OSTI ID: 115831
• Journal Information: Physical Review, B: Condensed Matter, Journal Name: Physical Review, B: Condensed Matter Journal Issue: 9 Vol. 52; ISSN PRBMDO; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
BORON CARBIDES
CRYSTAL DEFECTS
ENERGY GAP
GRANULAR MATERIALS
NICKEL CARBIDES
SUPERCONDUCTORS
TRANSITION TEMPERATURE
TUNNEL EFFECT
YTTRIUM CARBIDES