Jc enhancement and flux pinning in Y1−xGdxBCO and (Gd, Eu) codoped Y0.9−yEuyGd0.1BCO thin films by TFA-MOD

• Eu and Gd codoped Y0.9−yEuyGd0.1BCO thin films were prepared by TFA-MOD.
• Critical current density was obviously improved by codoping.
• Flux pinning type was not changed with doping and codoping.

Y1−xGdxBa2Cu3O7−δ (0 ⩽ x ⩽ 0.5) thin films were prepared on LaAlO3 (0 0 1) substrates by trifluoroacetate metal organic deposition (TFA-MOD). It was observed that the critical current density under self-field of Y0.9Gd0.1Ba2Cu3O7−δ thin film was about two times higher than that of YBCO thin film within the range of 5–85 K. Then, codoped Y0.9−yEuyGd0.1BCO thin films (0 ⩽ y ⩽ 0.2) were fabricated by TFA-MOD. It was observed that the critical current density under magnetic fields was enhanced largely due to codoping. The flux pinning type was not changed with Gd doping and codoping, which could be attributed to the normal surface pins.