Persistent currents in Tl-Ba-Ca-Cu-O superconductors

Grader, G. S.; Gyorgy, E. M.; Van Uitert, L. G.; Grodkiewicz, W. H.; Kyle, T. R.; Eibschutz, M.
July 1988
Applied Physics Letters;7/25/1988, Vol. 53 Issue 4, p319
Academic Journal
We have demonstrated the presence of circulating circumferential currents in toroids of Tl-Ba-Ca-Cu-O superconductors at 77.3 and 90.2 K. The nominal composition was Tl1.5Ba2Ca2Cu3Ox; however, both the x-ray diffraction pattern and the Meissner effect indicate the presence of more than one phase. The circulating current was found to decrease by 27% in 3.8×103 s. The nature of the above time dependence is not consistent with the presence of a simple ohmic resistance but rather indicates that a process such as flux creep is the cause of this decay. An estimated upper limit of the resistivity is 1.3×10-14 Ω cm at 77.3 K.


Related Articles

  • New family of high Tc superconductors in the (Tl1-xMx)Sr2(Ca1-yYy)Cu2O7-δ system (M=IVA and VA elements). Liu, R. S.; Zhou, W.; Edwards, P. P. // Applied Physics Letters;12/3/1990, Vol. 57 Issue 23, p2492 

    A new family of high Tc superconductors with superconducting transition temperatures ranging from 40 to 100 K have been synthesized in the (Tl1-xMx)Sr2 (Ca1-yYy)Cu2O7-δ (M=Ti, Zr, Hf, V, Nb, and Ta) system. Here, we use as an example, vanadium and yttrium substitution into the thallium and...

  • Metalorganic chemical vapor deposition of Tl2CaBa2Cu2Oy superconducting thin films on sapphire. Zhang, K.; Boyd, E. P.; Kwak, B. S.; Wright, A. C.; Erbil, A. // Applied Physics Letters;9/18/1989, Vol. 55 Issue 12, p1258 

    Superconducting Tl2CaBa2Cu2Oy thin films have been successfully grown on the single-crystal sapphire (1102) substrate by using the metalorganic chemical vapor deposition technique. The growth rate of the films was about 5 μm/h. The as-deposited film was post-annealed in a partially sealed...

  • Scanning tunneling microscopy investigations of the local structure of Tl2Ba2CaCu2O8 single crystals. Wu, X. L.; Lieber, C. M.; Ginley, D. S.; Baughman, R. J. // Applied Physics Letters;11/13/1989, Vol. 55 Issue 20, p2129 

    The in-plane structure of single-crystal samples of Tl2Ba2CaCu2O8 has been imaged at room temperature using a scanning tunneling microscope. Atomic-resolution surface images exhibit areas in which the structure has tetragonal symmetry (peak spacing 2.5±0.2 Å) and regions in which the...

  • New family of thallium cuprate superconductors not containing calcium or barium: TlSrn+1-xLnxCunO2n+3+δ (Ln=La, Pr, or Nd). Ganguli, A. K.; Manivannan, V.; Sood, A. K.; Rao, C. N. R. // Applied Physics Letters;12/18/1989, Vol. 55 Issue 25, p2664 

    The first two members of the new TlSrn+1-xLnxCunO2n+3+δ (Ln=La, Pr, or Nd) series of superconducting cuprates possessing 1021 and 1122 type structures are described. The n=1 (1021) members with Tcs around 40 K have electrons or holes as the majority charge carriers depending on x. The n=2...

  • Formation of superconducting (Tl,Bi)Sr2CaCu2Oy thin films by rf sputtering and thallium diffusion. Liu, R. S.; Edwards, P. P.; Hunneyball, P. D.; Bennett, M. J.; Jedamzik, D.; Harrison, M. R.; Horley, R. J. // Applied Physics Letters;5/21/1990, Vol. 56 Issue 21, p2135 

    We have prepared new high Tc superconducting thin films of (Tl,Bi)-Sr-Ca-Cu-O by combining low temperature (500 °C) rf sputtering of Bi-Sr-Ca-Cu-O precursor films and thallium diffusion. A typical film has Tc(onset) =80 K, Tc(midpoint) =79 K, and Tc(zero) =50 K. X-ray diffraction and energy...

  • Flux creep characteristics in high-temperature superconductors. Zeldov, E.; Amer, N. M.; Koren, G.; Gupta, A.; McElfresh, M. W.; Gambino, R. J. // Applied Physics Letters;2/12/1990, Vol. 56 Issue 7, p680 

    We describe the voltage-current characteristics of YBa2Cu3O7-δ epitaxial films within the flux creep model in a manner consistent with the resistive transition behavior. The magnitude of the activation energy, and its temperature and magnetic field dependences, are readily derived from the...

  • Electron Raman scattering in Tl2Ba2CuO6+x crystals. Zaitsev, S. V.; Maksimov, A. A.; Tartakovskii, I. I. // JETP Letters;12/10/96, Vol. 64 Issue 11, p808 

    It is inferred from the position of the 2Δ peak in the electron light scattering spectra that in a sample with high Tc≊90 K the ratio 2Δ/Tc is approximately equal to 6 and 7 for different polarizations, while in overdoped samples with Tc≊40 and 35 K the 2Δ peak is...

  • Microwave surface resistance of bulk Tl-Ba-Ca-Cu-O superconductors. Newman, H. S.; Singh, A. K.; Sadananda, K.; Imam, M. A. // Applied Physics Letters;1/23/1989, Vol. 54 Issue 4, p389 

    The first measurements of the microwave surface resistance at 18 GHz of bulk Tl-Ba-Ca-Cu-O superconductors produced by the hot isostatic pressing (HIP) process are reported. The superconducting samples, prepared by solid-state reaction with subsequent sintering and consolidation to obtain ideal...

  • Effect of an external magnetic field and a trapped magnetic flux on the current-voltage characteristics of a granular high-temperature superconductor YBa2Cu3O7−δ. Derevyanko, V. V.; Sukhareva, T. V.; Finkel', V. A. // Physics of the Solid State;Aug2006, Vol. 48 Issue 8, p1455 

    A comparative study of the current-voltage characteristics of the high-temperature ceramic superconductor YBa2Cu3O∼6.95 at T = 77.3 K is performed over wide ranges of external magnetic fields H ext and “treatment” fields H treat. It is found that the field dependences of the...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics