REBCO mixtures with large difference in rare-earth ion size: superconducting properties of chemical solution deposition-grown Yb1−xSmxBa2Cu3O7−δ films

<p>Yb_1-<i>x</i>Sm<i>_x</i>Ba₂Cu₃O_7-_dfilms have been prepared by chemical solution deposition following the Extremely-Low-Fluorine route, which allows reducing the fluorine content by 93% with respect to standard TFA solutions. The obtained results show that, on the one hand, <i>T</i>_c remains stable at ~ 90 K with Sm content up to <i>x </i>= 0.5 where <i>T</i>_c starts to increase towards the values of pure SmBCO films of ~ 95 K. On the other hand, the critical current densities <i>J</i>_c of the pure SmBCO films are the largest at 77 K, where the influence of a higher <i>T</i>_c is very relevant, while at lower temperatures and low fields, the mixed films reach larger values. This demonstrates that mixing rare earth elements <i>RE</i> in <i>RE</i>Ba₂Cu₃O_7-_d causes a change in the pinning properties of the films and reveals the importance of selecting adequate <i>RE</i>BCO compounds according to the temperature and magnetic field region where a specific application operates.</p>