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Title: A close correlation between nanostructure formations and the thickness dependence of the critical current density in pure and BaSnO{sub 3}-added GdBa{sub 2}Cu{sub 3}O{sub 7-δ} films

A close correlation between the nanostructure formations and the thickness dependence of the in-field critical current density (J{sub c}) in GdBa{sub 2}Cu{sub 3}O{sub 7-δ} (GdBCO) films is reported. Pure and 2 wt. % BaSnO{sub 3} (BSO)-added GdBCO films with film thicknesses (d) ranging from 0.2 μm to 1.5 μm were deposited on SrTiO{sub 3} single-crystalline substrates by using a pulsed laser deposition technique. Magnetization data measured at 77 K with the magnetic field applied parallel to the c-axis of the films showed the general trend of decreasing in-field J{sub c} with increasing residual film thickness. The two special inversions, however, were observed at d ∼ 0.6 μm, for which the J{sub c}’s of both the pure and BSO-added GdBCO films were larger than those of the films with d ∼ 0.4 μm. A sequential ion-milling process and scanning electron microscopy studies were employed to examine the microstructural evolution in the 1.5- μm-thick GdBCO films. For the pure GdBCO films, nanosized dislocations were observed to start growing at intersections of perpendicularly connected a-axis-oriented grains in a residual film thickness (t) of ∼ 0.6 μm and the growth persisted to the top surface of the 1.5-μm-thick GdBCO film. For the BSO-added GdBCO films, the density of BSO nanorods was estimatedmore » to be decreased versus t with an increase found at t of ∼ 0.6 μm A reason for this inversions of J{sub c} might be the nanostructure formations at t ∼ 0.6 μm, which were proved to serve as effective pinning centers.« less
Authors:
; ;  [1] ; ;  [2]
  1. Department of Physics, Chungbuk National University, Cheongju 361-763 (Korea, Republic of)
  2. Department of Physics, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)
Publication Date:
OSTI Identifier:
22275585
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 16; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 77 NANOSCIENCE AND NANOTECHNOLOGY; BARIUM COMPOUNDS; CORRELATIONS; CRITICAL CURRENT; CUPRATES; CURRENT DENSITY; DISLOCATIONS; ENERGY BEAM DEPOSITION; GADOLINIUM COMPOUNDS; HIGH-TC SUPERCONDUCTORS; LASER RADIATION; MAGNETIC FIELDS; MAGNETIZATION; MICROSTRUCTURE; MONOCRYSTALS; NANOSTRUCTURES; PULSED IRRADIATION; SCANNING ELECTRON MICROSCOPY; STANNATES; STRONTIUM TITANATES; SUPERCONDUCTING FILMS; THICKNESS