The Vortex Path Model Analysis of the Field Angle Dependence of the Critical Current Density in Nanocomposite YBa2Cu3 O 7−x – BaZrO3 Films Obtained by Low Fluorine Chemical Solution Deposition

Abstract

In the present paper, we analyze the role of in situ grown BaZrO3 (BZO) inclusions in YBa2Cu3O7−x (YBCO) thin films prepared by chemical solution deposition using a low fluorine coating solution, on the field angle dependence of the critical current density, Jc(), data using the vortex path model. In order to form a coherent picture on the BZO doping influence on the pinning properties of the YBCO matrix, detailed structural analyses performed by X-ray diffraction techniques and microstructural evaluation by transmission electron microscopy are also presented. The evaluation of different contributions to the overall, Jc, permitted us to prove the effectiveness of the BZO inclusions acting as isotropic pinning centers, reflected in a uniform component of high relative value with respect to other components. For the studied 10 mol % BZO doping concentration, a threefold increase in the critical current density, Jc, of the YBCO host is measured, in self-field at 77 K, corresponding to a value of Jc=2.9MA/cm2, whereas a factor 10 is measured at 1 T (Jc=0.35 MA/cm2). © 2014, Springer Science+Business Media New York

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

“…The irreversibility field H irr at 77 K increased from 7.5 to 8.4 T by the introduction of 5 mol % nanocrystal, and the maximum pinning force density F P,max more than tripled from 1.6 to 5.5 GN m –3 at 77 K (Table and Figure D). This is a record pinning force value for LF-YBCO films . At lower temperatures, the increase of F P is similar, but somewhat lower (Figure B,C).…”

“…This is a record pinning force value for LF-YBCO films. 50 At lower temperatures, the increase of FP is similar but somewhat lower ( Figure 7B and C). These values are slightly lower than the champion value (10-22 GN m -³, 77 K) reported from the spontaneous segregation of BaZrO3 particles in CSD-YBCO films 21 but improved compared to earlier reports on BaZrO3 particles in LF-YBCO (3.8 GN m -³) 50 , and our results have the additional advantage of being highly reproducible.…”

“…50 At lower temperatures, the increase of FP is similar but somewhat lower ( Figure 7B and C). These values are slightly lower than the champion value (10-22 GN m -³, 77 K) reported from the spontaneous segregation of BaZrO3 particles in CSD-YBCO films 21 but improved compared to earlier reports on BaZrO3 particles in LF-YBCO (3.8 GN m -³) 50 , and our results have the additional advantage of being highly reproducible. The self-field Jc is still high for doped YBCO, so we believe that the FP,max can be increased by the addition of more ZrO2 nanocrystals in the YBCO matrix if they remain small in the order of superconducting coherence length (2-4 nm for YBCO at 77 K) and agglomeration-free (to reach a higher number density of defects in YBCO matrix) without affecting the YBCO microstructure.…”

High Critical Current Density and Enhanced Pinning in Superconducting Films of YBa2Cu3O7−δ Nanocomposites with Embedded BaZrO3, BaHfO3, BaTiO3, and SrZrO3 Nanocrystals

“…The maximum F p (5.9 GN/m 3 ) of the BHO nanocomposite compares favorably to previous YBCO films with preformed BHO and BZO nanocrystals , (with maximum pinning forces between 2.2 and 4.5 GN/m 3 ) despite the much higher nanocrystal load used in these works (20 mol %) and the use of all-TFA YBCO inks. It also compares favorably to YBCO films with in situ formation of pinning centers deposited by low-fluorine CSD such as a 5 mol % BZO–YBCO film (4.6 GN/m 3 ), a 10 mol % BZO–YBCO film (3.8 GN/m 3 ), or a 12 mol % BHO–YBCO film (4.1 GN/m 3 ). However, it is still far from the record F p values of in situ YBCO films grown by the all-TFA route (22 GN/m 3 in a 10 mol % BZO–YBCO film)…”

Comparative study of CSD-grown REBCO films with different rare earth elements: processing windows and T c

“…Thereby, precipitates grown by CSD are known to lead to the largest reductions of the J c anisotropy of REBCO with sometimes near-isotropic J c in a certain field and temperature range, see e.g. [39][40][41].…”