Relationship between vortex pinning properties and microstructure in Ba-Nb-O-doped YBa2Cu3Oy and ErBa2Cu3Oy films

In-field Jcs were improved by introducing Ba-Nb-O (BNO)-nanorods in YBa2Cu3Oy (Y123) and ErBa2Cu3Oy (Er123) films. Retention of Jc against the magnetic field for the BNO-doped Er123 film was superior to that for the BNO-doped Y123 film. Sharp distribution of local critical current density originating from vortex pinning by nanorods with uniform morphology was demonstrated in the Er123 film. On the other hand, fluctuating microstructures of nanorods formed in the Y123 film prepared by the same deposition conditions. Moreover, different growth temperature dependences of nanorod morphology between the Y123 and Er123 films were clarified.