Thick High &lt;inline-formula&gt; &lt;tex-math notation="LaTeX"&gt;$J_\mathrm{c} $&lt;/tex-math&gt;&lt;/inline-formula&gt; YBCO Films on ABAD-YSZ Templates

Self Cite

Recent efforts in the development of YBa2Cu3O7-x (YBCO) coated conductors are devoted to the increase of the critical current Ic in magnetic fields. This is typically realized by growing thicker YBCO layers as well as by the incorporation of artificial pinning centers. We studied the growth of doped YBCO layers with a thickness of up to 7 µm using pulsed laser deposition with a growth rate of about 1.2 nm/s. Industrially fabricated ion-beam textured YSZ templates based on metal tapes were used as substrates for this study. The incorporation of BaHfO3 (BHO) or Ba2Y(Nb0.5Ta0.5)O6 (BYNTO) secondary phase additions leads to a denser microstructure compared to undoped films. A purely c-axis-oriented YBCO growth is preserved up to a thickness of about 4 µm, whereas misoriented texture components were observed in thicker films. The critical temperature is slightly reduced compared to undoped films and independent of film thickness. The critical current density Jc of the BHO-and BYNTO-doped YBCO layers is lower at 77 K and self-field compared to pure YBCO layers; however, Ic increases up to a thickness of 5 µm. A comparison between films with a thickness of 1.3 µm revealed that the anisotropy of the critical current density Jc() strongly depends on the incorporated pinning centers. Whereas BHO nanorods lead to a strong B||c-axis peak, the overall anisotropy is significantly reduced by the incorporation of BYNTO forming a mixture of short c-axis-oriented nanorods and small (a-b)oriented platelets. As a result, the Jc values of the doped films outperform the undoped samples at higher fields and lower temperatures for most magnetic field directions.

Section: Resultsmentioning

confidence: 68%

Section: Growth Of Thick Ybco Films With Artificial Pinning Centersmentioning

confidence: 80%

Section: Introductionmentioning

confidence: 80%

See 1 more Smart Citation

Influence of artificial pinning centers on structural and superconducting properties of thick YBCO films on ABAD-YSZ templates

Pahlke

Sieger

Ottolinger

et al. 2018

Self Cite

“…One of the biggest challenges in (RE)Ba 2 Cu 3 O 7−δ (REBCO, RE = rare Earth metal) coated conductor fabrication is the strong degradation of the critical current density, J c , with increasing thickness of the superconducting layer. Various studies find that the increase in thickness leads to the formation of cracks, voids, misorientation, impurities and other phases that block current flow [1][2][3]. A promising method to overcome this problem is the use of substrates made by the inclined substrate deposition (ISD) technique.…”

Section: Introductionmentioning

confidence: 99%

Critical current anisotropy of GdBCO tapes grown on ISD–MgO buffered substrate

Lao

Bernardi

Bauer³

et al. 2015

The critical current anisotropy of a GdBa 2 Cu 3 O 7 (GdBCO) coated conductor (CC) was investigated. The MgO buffer layer was grown by the inclined substrate deposition (ISD) technique leading to a tilted c-axis growth of the GdBCO layer by 24°from the tape normal. The J c was measured in two current directions: longitudinal and transverse to the tape. The self-field J c in the 2 μm thick GdBCO layer was 1.3 MA cm −2 and 0.88 MA cm −2 at 77 K in the longitudinal and transverse directions, respectively. The 30% lower value in the transverse direction results from the current flow across the weakly superconducting layer of GdBCO. The peak in the J c -anisotropy corresponding to intrinsic pinning appears at 24°with respect to the tape surface in the longitudinal direction and the anisotropy was highly asymmetric in a wide range of fields. Due to the large crystallographic tilt of the GdBCO with respect to the tape axes, a minimum caused by vortex channeling occurred in the transverse current direction which was observed for the first time at 77 K. Another consequence of the large crystallographic tilt angle is a pronounced competing effect of the crystallographic anisotropy and Lorentz force on J c in the variable Lorentz force configuration.

“…In combination with a particle diameter of d P 12 nm, the distance between two particles is of the order of the particle diameter, the surface coverage A P ≈25% and a disturbed growth of the YBCO matrix likely. Furthermore, the formation of unfavorably large pores, acting as current blockers, might be enhanced for larger areal particle densities, similar to larger Y 2 O 3 precipitates [25].…”

Section: Superconducting Properties Of the Heterostructuresmentioning

confidence: 99%

Controlling particle properties in ${\mathrm{YBa}}_{2}{\mathrm{Cu}}_{3}{{\rm{O}}}_{7-\delta }$ nanocomposites by combining PLD with an inert gas condensation system

Sparing¹,

Reich²,

Hänisch³

et al. 2017

The critical current density in thin films, which limits their application in external magnetic fields, can be enhanced by the introduction of artificial pinning centers such as non-superconducting nanoparticles inducing additional defects and local strain in the superconducting matrix. To understand the correlation between superconductivity, defect structures and particles, a controlled integration of particles with adjustable properties is essential. A powerful technique for the growth of isolated nanoparticles in the range of 10 nm is dc-magnetron sputtering in an inert gas flow. The inert gas condensation (IGC) of particles allows for an independent control of both the particle diameter distribution and the areal density. We report on the integration of such gas-phase-condensed nanoparticles into pulsed laser deposited (PLD) thin film multilayers with a combined PLD-IGC system. The particles and the structure of the multilayers are analyzed by transmission electron microscopy on cross-sectional FIB lamellae. As a result of the IGC particle implementation, randomly as well as biaxially oriented precipitates are formed in the thin films. With as few as three interlayers of nanoparticles, the pinning force density is enhanced in the low-field region.