We report on transport properties of grain boundaries fabricated in YBa2Cu3O7-x thin films grown by the liquid phase epitaxy (LPE) technique on MgO asymmetrical bicrystal substrate with 45o misorientation angle. In total around 10 samples have been studied. Substantial scatter of zero field values of the critical current density at 5K has been observed. The upper limit of Jc of the order of 104 A/cm2 found in our study is close to previously reported data for 45o bicrystals grown by various physical vapour deposition methods while the minimal value of Jc for the LPE grown bicrystals in striking difference to the results published before is exactly equal to zero. For samples with non-zero Jc we have found a few different types of critical current dependence on magnetic field ranging from pattern reminiscent Fraunhover-like Ic(H) to Ic(H) profile with Ic minimum at zero field.
Download