[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.
Physica C Superconductivity 12/2003; · 1.11 Impact Factor
[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.
IEEE Transactions on Applied Superconductivity 07/2003; · 1.32 Impact Factor