[Show abstract][Hide abstract] ABSTRACT: The influence of neutron irradiation on the angular, field and temperature dependence of the critical transport current density Jc of YBa2Cu3O7−δ (Y-123) thick films, as well as on the irreversibility fields was investigated. The specimens were deposited by liquid phase epitaxy either directly on NdGaO3 or on seeded (1 0 0)MgO substrates with a final Y-123 layer thickness of 1 and 5–10 μm, respectively. XRD of the superconducting layers proves good in-plane and out-of-plane alignments with FWHM’s below 2°. The specimens showed excellent irreversible properties with critical current densities of up to 3 × 109 A/m2 at zero field and 77 K and irreversibility fields above 7 T at 77 K for H∥c prior to neutron irradiation, which was performed in fast neutron fluence steps of 1021 m−2, corresponding to 5 × 1021 defect cascades per m3 per step. Jc enhancements by 100% and an anisotropy reduction by a factor of 2 are achieved at the optimum neutron fluence.
Full-text · Article · Dec 2003 · Physica C Superconductivity
[Show abstract][Hide abstract] ABSTRACT: Results on the angular and the field dependence of the critical transport current density as well as on the temperature dependence of the irreversibility fields in YBa<sub>2</sub>Cu<sub>3</sub>O<sub>7-δ</sub> coated conductors are presented. The films were deposited by pulsed laser deposition on (Y<sub>2</sub>O<sub>3</sub>/YSZ/CeO<sub>2</sub>) triple buffer structures. Either textured magnetic Ni-Fe alloys or recently developed nonmagnetic Ni-Cr-W alloys with good biaxial texture (8.4° and 9.4° for ω and φ scans) were used as substrates. The influence of artificial pinning centers, introduced by fast neutron irradiation, on the irreversible properties of the YBCO films is discussed.