Interrelations among zero-field critical current density, irreversibility field and pseudogap in hole doped high-Tc cuprates

The effects of hole content (p) and oxygen deficiency (delta) on the zero-field critical current density, Jc0, were investigated for high-quality c-axis oriented Y1-xCaxBa2Cu3O7-delta (x = 0, 0.05, 0.10, 0.20) thin films. Low temperature density these films above optimum doping found to be high primarily determined by concentration, reaching a maximum at p ~ 0.185 +/- 0.005, irrespective level deficiency. This implies that disorder plays only secondary role intrinsic Jc0 is governed carrier concentration in copper oxide planes. Further support favor this was from analysis in-plane resistive transitions crystalline YBa2Cu3O7-delta (YBCO) under magnetic fields (H) applied along c-direction, over wide range doped holes. characteristic field (H0), linked vortex activation energy irreversibility field, exhibits similar p-dependence as shown Jc0(p). We have explained observations terms dependent pseudogap (PG) low-energy electronic states. Both depend directly superconducting condensation energy, which turn largely controlled magnitude PG quasiparticle spectral density.