Home
For authors
Submission status

Current
Archive
Archive (English)
   Volumes 21-40
   Volumes 1-20
   Volumes 41-62
      Volume 62
      Volume 61
      Volume 60
      Volume 59
      Volume 58
      Volume 57
      Volume 56
      Volume 55
      Volume 54
      Volume 53
      Volume 52
      Volume 51
      Volume 50
      Volume 49
      Volume 48
      Volume 47
      Volume 46
      Volume 45
      Volume 44
      Volume 43
      Volume 42
      Volume 41
Search
VOLUME 60 (1994) | ISSUE 6 | PAGE 410
Point-contact and tunneling spectroscopy of YBa2Cu3O7-x and YbBa2Cu3O7-x (90-K phase) single crystals
Point-contact and tunneling spectroscopy has been used to determine the gap parameter Δ of single crystals of YBa2Cu307_x [28 meV =£ ä (4.2 K) =s 33 meV] and YbBa2Cu307_^ [29 meV =s Δ (4.2 ë) « 32 meV], with transition temperatures 87=£çÓ=Å90 ë. An additional fine structure has been observed on the current-voltage characteristics of point contacts containing a subharmonic structure [Vn = 2A/(en)]. This additional structure may stem from a quantum size effect in the quasiparticle spectrum in the N transition region of the S-N-S point contact. Current-voltage characteristics with a small excess current in the subgap region have been observed for 5-7-5 tunnel junctions. The shape of the current-voltage characteristics of the S-I-S contacts can be described well by the semiempirical Dynes model. A ratio Γ/Δ = 0.07, where ç is a smearing parameter (T=4.2 K), has been found. This is a record-low value for high-IT,. superconducting tunnel junctions. © 1994 American Institute of Physics.