Critical current density and pinning potential in YBa2Cu3O7-delta thick films ablated from a BaZrO3-doped nanocrystalline target




Crisan A, Kechik MMA, Mikheenko P, Dang VS, Sarkar A, Abell JS, Paturi P, Huhtinen H

PublisherIOP PUBLISHING LTD

2009

Superconductor Science and Technology

SUPERCONDUCTOR SCIENCE & TECHNOLOGY

SUPERCOND SCI TECH

045014

22

4

5

0953-2048

DOIhttps://doi.org/10.1088/0953-2048/22/4/045014(external)



We report on the pulsed laser deposition and characterization of thick (1.27 mu m) films ablated from a nanocrystalline YBa2Cu3O7-delta (YBCO) target doped with 4 wt% BaZrO3 (BZO), nYBCO/BZO. DC magnetization measurements have shown a four-to five-fold increase in the critical current density J(c) and a three- to four-fold increase in the maximum pinning force in comparison with 1 mu m thick films grown from a commercial microcrystalline YBCO target, at both 77.3 and 65 K. We have found that the frequency-dependent critical current densities J(c)(f(0)/f) estimated from susceptibility measurements are linear in a double-logarithmic plot ( where f is the frequency of the AC field and f(0) is a macroscopic attempt frequency of about 10(6) Hz), consistent with a logarithmic dependence of the pinning potential on the current density, and are again several times higher in nYBCO/BZO thick films. From the slopes of the J(c)(f(0)/f) dependences we have also estimated the values of pinning potentials in fields between 3 and 5 T.



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