Anisotropy of Critical Current Density and Flux Pinning in Sputtered Y1Ba2Cu3O7−y Films

Abstract

The critical current density, J c , in sputter deposited Y1Ba2Cu3O7−y film was measured at various temperatures, magnetic fields and field directions. The anisotropy of J c was large at high magnetic fields but became smaller with decreasing magnetic field. Moreover, a crossover in J c (B) was observed at T<65K and B<2T; the value of J c for field perpendicular to the ab-plane (B ⊥ ab) was larger than that for parallel one (B ∥ ab). In angular dependence of J c(θ), two peaks were observed at B ∥ ab and B ⊥ ab. One peak for B ∥ ab was sharp and another one around B ⊥ ab was a broad maximum, respectively. The results are discussed on the anisotropy of flux pinning mechanism; the intrinsic flux pinning and the twin boundary flux pinning.