Angular Dependence of Critical Current Density in Y-Ba-Cu-O Thin Films

Abstract

axis oriented YBa 2 Cu 3 O 7 (YBCO) thin films for coated conductor applications have anisotropic behaviors of critical current density ( ) in magnetic fields. The anisotropic vortex pinning in YBCO films fabricated on SrTiO 3 (100) single crystal substrates by pulsed laser deposition was investigated based on the field angular dependencies of , which were measured using the constant Lorentz force configuration (CLFC) and a variable Lorentz force configuration (VLFC).( ) as a function of angle between the -plane direction and the magnetic field direction had a sharp peak at = 0 , which was attributed to the intrinsic pinning. Besides, ( ) did not depend on the intensity of the Lorentz force when the magnetic field was applied near = 90 . This indicates that ( ) in this region is determined by the depinning of the vortex segment trapped by the pinning centers parallel to -axis of the film. A transition from the intrinsic pinning to the extrinsic pinning is also discussed.Index Terms-Critical current density, Lorentz force, vortex pinning, YBCO thin film.

Structural and Superconducting Properties of Undoped and BZO-doped GdBCO Thin Films

“…Because crystal defects act as pinning sites, the increase of in GdBCO is connected to the observed high density of defects including stacking faults [2], [13], [14]. In addition, pinning can be enhanced by adding some artificial pinning sites such as gold nanorods [15], [16], Gd/Ba substitution [17] and adding non-superconducting impurities such as yttrium-stabilized zirconium [13] or (BZO) [7], [8]. BZO has been found to increase the dislocation concentration and it induces extended columnar linear defects in the films [18]- [20].…”

Characterization of BaZrO3 nanocolumns in Zr-added (Gd, Y)Ba2Cu3O x superconductor tape by anomalous small-angle x-ray scattering

“…Small-angle x-ray scattering (SAXS) is a suitable technique to quantitatively characterize the nanostructures of a wide variety of materials because it offers a larger gauge volume compared to electron microscopes [10][11][12][13]. In particular, x-rays can penetrate the REBCO tapes and provide bulk average nanostructural information [13]. However, SAXS often gives complicated results because it measures not only the nanocolumns but also other nanostructures present in REBCO tapes.…”

High $I_{\rm c}$ in YBCO Films Grown at Very High Rates by Liquid Mediated Growth

“…In this paper, we further explore enhancement of nanoscale pinning by assistance of a noble metal. It is known for some time that Au can get into bulk YBCO occupying Cu (1) to 0.3%), with increasing up to 1.5 K in the saturation limit of 10 mol% Au [12], [13]. Apart from affecting properties, in YBCO films, noble metal is expected to influence growth of both, YBCO mother phase and eventual nano-inclusions.…”