Enhancement Of Flux Pinning By H+ And Xe+ Irradiation In Epitaxial Thin-Films Of Ba2ycu3o7-Delta

Epitaxial Ba2YCu3O7-delta (BYCO) films grown by the ex situ BaF2 process are comparable to single crystals both in crystalline quality and the value and temperature dependence of the critical current (J(c)) in all applied magnetic field in thc BYCO (001) direction of H(a)=0.9 T. With the appropriate dose of either 2 MeV H+ or Xe-135+, we can enhance J(c) by a factor of 2 in H(a)=0.9 T with little effect on T(c). This is significantly greater than the approximately 25% enhancement previously reported for epitaxial BYCO films grown by in situ techniques [Roas, Hensel, and Saemann-Ischenko, Appl. Phys. Lett. 54, 1051 (1989). This provides the opportunity to isolate the induced defects and study their properties.