Vortex pinning in chemical solution nanostructured YBCO films

Abstract

A methodology of general validity to study vortex pinning in YBa 2 Cu 3 O 7−δ (YBCO) is described. It is based on measuring the angular-dependent critical current density in a large range of temperatures and magnetic fields and it permits one to identify, separate and quantify the three basic vortex pinning contributions associated to anisotropic-strong, isotropic-strong and isotropic-weak pinning centers. The corresponding vortex pinning phase diagrams for these three contributions are built up. This methodology is applied to the recently discovered solution-derived YBCO-BaZrO 3 nanocomposites which display a maximum vortex pinning force of 78 GN m −3 at 65 K, being five times larger than that of NbTi at 4.2 K. These nanocomposites show an effective anisotropy tending to unity and the best superconducting properties observed so far in YBCO. We present the richness and complexity of their microstructure and the correlation with the vortex pinning properties. The application of the vortex pinning methodology and comparison with a standard solution-derived YBCO film enable us to identify the isotropic-strong defect contribution being at the origin of their unique properties.

RETRACTED: Doping of Tin-oxides pinning centers into YBCO films by MOD method

“…Recently, researches of J c enhancement for REBCO films have been proceeded by introducing artificial pinning centers into the films. It has been reported that J c properties in magnetic fields were well improved for REBCO films with pinning centers such as RE 2 O 3 and BaZrO 3 nano compounds or Ce-Gd-O nanowalls by the MOD process using TFA salts [5][6][7][8][9]. On the other hand, we have been reported that BaSnO 3 nano rods acted stronger than BaZrO 3 as pinning centers in REBCO film grown by a pulsed laser deposition method [10].…”

Optimizing Nanocomposites through Nanocrystal Surface Chemistry: Superconducting YBa2Cu3O7 Thin Films via Low-Fluorine Metal Organic Deposition and Preformed Metal Oxide Nanocrystals

“…1 Electric power applications such as motors and generators, require engineering critical current densities of 30 to 40 kA cm -² at 55 to 65 K in operating fields of 3 to 5 T. 2 Unfortunately, YBCO films typically exhibit a strong reduction of the critical current density (Jc) with increasing magnetic field strength caused by vortex motion. 3 The incorporation of nano-sized defects has proven to be an effective approach to achieve the immobilization of vortices, i.e. flux pinning.…”

Solution design for low-fluorine trifluoroacetate route to YBa2Cu3O7films

“…In addition, the nucleation and growth mechanisms for this modified solutions should be further analyzed to ensure best performance. The modification of the solutions intends to reach more environmental friendly processes, enhanced thickness, planarized final HTS layers and generation of artificial pinning centers by growing nanocomposites [8] [9]. For that reasons, different additives in the precursor solutions have been used in the form of organic molecules (monomers or polymers) or inorganic salts [10] [11].…”