Enhancement and angular dependence of transport critical current density in pulsed laser deposited YBa2Cu3O7−x+BaSnO3 films in applied magnetic fields

Abstract

Y Ba 2 Cu 3 O 7 − x (YBCO) films with nanoparticles of BaSnO3 (BSO) were processed using pulsed laser ablation of a special target made with dual phase sectors of YBCO and BSO. Transport critical current density (Jct) of these YBCO+BSO films in applied magnetic fields and angular dependence of Jct on the applied field orientation was measured. It was observed that in the YBCO+BSO films, the Jct (H‖c orientation) increased considerably as compared to regular YBCO films and was 1.3 times higher than Jct in H‖ab orientation. Cross-sectional transmission electron microscopy images on YBCO+BSO films showed the presence of high density (3.5×1011cm−2) of nanoparticles (∼10nm size) and nanocolumns that extended throughout the thickness of the films with high density of dislocations and stacking faults (1000μm−2). The observed results of enhancements in Jct in H‖c and Jct in H‖ab orientations were discussed in the light of the observed microstructural details.

Thick YBa2Cu3O7−x+BaSnO3 films with enhanced critical current density at high magnetic fields

“…YBCO+ BSO thin films prepared by this method were found to have high T c , high J c in both H / /c, and H / /ab orientations in high magnetic fields. 19 More than an order of magnitude improvement in J c was observed in 300 nm thick film samples as compared to YBCO samples of similar thickness at 5 T, H / /c. 10 Recently Mele et al 12 compared the performance of YBCO+ BZO and YBCO+ BSO thin films as well and showed that the films with BSO have higher pinning force.…”

“…Other defects such as dislocations, strain fields, and stacking faults were also found to be present in thick films similar to the nanocolumns and defects observed in previously reported 300 nm thick YBCO+ BSO films. 19 The mechanism for such a microstructure formation is believed to be due to the strain energy minimization that exists due to the lattice mismatch ͑7.7%͒ between BSO and YBCO. A high density of continuous, solid BSO nanocolumns and associated defects, and increased irreversibility field are responsible for the improved properties observed in YBCO+ BSO films.…”

“…A dual-phase sectored PLD target approach, which is discussed in detail elsewhere, [19][20][21] was used to process the thick films. Essentially, a thin disk of a BSO sector is adhered to the top surface of a YBCO target and as the target is rotated during the pulsed laser deposition, BSO is introduced into a growing YBCO film.…”

Flux Pinning Enhancement in YBa 2 Cu 3 O 7–x Films for Coated Conductor Applications

“…In contrast to the YBCO+Y211 fi lms, the YBCO+BSO fi lms were found to have many BSO nanocolumns, as shown in a cross -sectional TEM image ( Figure 5.4 a as well as in Ref. [37] ). In a plan view image, these nanocolumns appear to be nanoparticles, as shown in Figure 5.4 b.…”

Comparatively high in-field critical current in type-II superconductors from heterogeneous columnar pins: A molecular dynamics study

“…Evidence exists that this is primarily due to edge dislocations that thread the film along the c axis in PLD-YBCO [2]. The critical current of YBCO films in c-axis aligned applied magnetic field can also be enhanced substantially by the introduction of BaZrO 3 (BZO) or of BaSnO 3 (BSO) material that naturally form nanorods along the c axis during the film growth process [3][4] [5]. Such increases in the in-field performance of the critical current in YBCO films by columnar microstructures are very important to the development of second-generation high-T c superconducting wire technology.…”