Comparative study of thickness dependence of critical current density of YBa2Cu3O7-δ on (100) SrTiO3 and on rolling-assisted biaxially textured substrates

We investigated the dependence of critical current density (J(c)) on thickness of YBa2Cu3O7-delta (YBCO) films grown by pulsed laser deposition on (100) SrTiO3 (STO) and on rolling-assisted biaxially textured substrates (RABiTS). The thickness of YBCO films varied from 0.19 to 3 mum. The highest J(c)s of 5.3 and 2.6 MA/cm(2) at 77 K, self-field were obtained for 0.19-mum YBCO films on STO and RABiTS, respectively. J(c) was found to decrease exponentially with YBCO thickness on both substrates. However, the results suggest different mechanisms are responsible for the J(c) reduction in the two cases. On STO, growth of a-axis grains within c-axis films and broadening of the in-plane texture were observed in thick films. On RABiTS, degradation in cube texture as well as development of a porous surface morphology were found to correlate with film thickness.