Pulsed laser deposition of thick YBa2Cu3O7−δ films with J c≥1 MA/cm2

Abstract

Using pulsed laser deposition, YBa2Cu3O7−δ (YBCO) films ranging in thickness from 0.065 to 6.4 μm have been deposited on yttria-stabilized zirconia substrates with an intermediate layer of CeO2. The thinnest films have critical current densities of over 5 MA/cm2 at 75 K with zero applied field; as film thickness is increased, Jc decreases asymptotically to 1 MA/cm2. X-ray analysis of a 2.2-μm-thick film shows that the YBCO is predominantly c-axis oriented and textured in-plane, while a Rutherford backscattering spectrometry minimum channeling yield of ≊75% indicates that the film contains disordered material at this thickness.

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

“…However, when regular or some other flux pinned YBCO films are grown, their associated J c decreases asymptotically with increases in thickness at a given field and shows a significant decline with increases in magnetic field for a given film thickness. 5,6 Even previously announced nanoparticle pinned YBCO films show the rapid deterioration in J c as the magnetic field is increased due to the lack of effective high-field flux pinning centers. 7,8 etc., are added in the YBCO film matrix to improve the J c and more efforts are still ongoing worldwide.…”

“…5 In applied magnetic fields, the J c of 1 m thick YBCO films decrease further, showing a J c of ϳ10 4 A / cm 2 at 7 T. 6 It is proposed that degradation in the degree of crystallinity, or throughthickness cation disorder level variations could be partially responsible. 14,15 One of the methods to overcome the J c dependence on the film thickness is to grow alternate layers of CeO 2 and YBCO.…”

“…These films showed a significantly reduced decline of the J c with thickness, especially at high magnetic fields. For example, a 2-µm-thick YBCO+BSO film had a J c ~3×10 5 A/cm 2 at 5 T as compared to a typical J c of 2.4×10 3 A/cm 2 at 5 T for a 300-nm-thick YBCO film. The thick YBCO+BSO films maintained high T c (>88 K) and had a high density (2.5×10 11 /cm 2 ) of continuous BSO nanocolumns that likely contributed for the observed J c enhancements.…”

Angular-dependent vortex pinning mechanisms in YBa2Cu3O7 coated conductors and thin films

“…We must emphasize that the absolute values of J c cannot be directly compared in films of different thickness, as it is well known that the J c of films on both SCS and CC is thickness dependent. 7,8 It is not our purpose to investigate this effect; instead we will focus on the dependences of J c on H and Θ. The first observation is that, overall, the three sets of curves look similar, suggesting that the same types of pinning structures may be , can be mapped back to the J c vs. Θ plot for any H. The details of the procedure will be described elsewhere.…”

Response of fractal penetration of magnetic flux to disorder landscape in superconducting films

“…15,16 The c-axis oriented YBCO films with large-size defects were grown on single crystalline SrTiO 3 substrates using the BaF 2 ex-situ process, which produces large precipitates. Insulating Y 2 O 3 or CuO particles have a physical size s range 0.1 µm < s < 3 µm spaced at ~ a few µm apart and randomly dispersed in the YBCO matrix.…”