Slow voltage oscillations in Ag-doped superconducting Y–Ba–Cu–O

• Published in: Physica. C, Superconductivity Vol. 468; no. 15; pp. 1419 - 1423
• Main Authors: Altinkok, A., Yetiş, H., Kiliç, K., Kiliç, A., Olutaş, M.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 15.09.2008; Elsevier Science
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; COPPER OXIDE; DOPING; Electric potential; Exact sciences and technology; Flux pinning; MAGNETIC FIELD; Magnetic fields; Magnetoresistance; Oscillations; Physics; Properties of type I and type II superconductors; Silver; SUPERCONDUCTIVITY; SUPERCONDUCTORS; Transport; Transport properties (electric and thermal conductivity, thermoelectric effects, etc.); Type-II superconductors; VOLTAGE; Vortex lattices ,flux pinning, flux creep; YBCO superconductors; YTTRIUM OXIDE; 74.25.Qt; Type-II superconductors; 74.72.Bk; Flux pinning; Magnetoresistance; Flux line; Voltage drop; Doping; Magnetic field effects; Oscillations; Order parameters; Relaxation; High-Tc superconductors; Transport processes; Non linear effect; Barium Copper Yttrium Oxides Mixed
• ISSN: 0921-4534; 1873-2143
• DOI: 10.1016/j.physc.2008.05.131

The time effects in Ag-doped YBa 2Cu 3O 7− x sample (YBCO/Ag) were examined by means of transport relaxation measurements ( V- t curves). At well-defined values of transport current ( I), temperature ( T) and external magnetic field ( H), an abrupt rise in sample voltage was observed at the early stage of the relaxation process. After reducing the initial current to a finite value, the sample voltage levels off within a very short time. The rapid voltage drops seen in V- t curves were attributed to the rapid dynamic reorganization of flux lines traversing the sample edges. These observations were also interpreted as an indication of doping of YBCO with Ag and easy suppression of superconducting order parameter due to the presence of Ag. In addition, we investigated the influence of bidirectional square wave (BSW) current on the evolution of V- t curves at different temperatures and external magnetic fields. It was observed that a nonlinear response seen in V- t curves to BSW current with sufficiently short periods or sufficiently low amplitude reflects itself as regular sinusoidal- type voltage oscillations, which were discussed mainly in terms of the dynamic competition between pinning and depinning.