Development of the technology for RE-123 superconducting films using RE-210

We developed a novel technology, using a mixture of Er₂BaO₄, BaCuO₂, and CuO, with an excess of Er at expense of Ba. Several micrometers thick films were prepared by screen-printing technique, spreading the mixture paste on silver substrates, processed then in Ar-1% pO₂ atmosphere. Using a double-step annealing, good quality Er-123 thick films were grown on silver substrates, with T_c onset 92 K. SEM and TEM analyses confirmed formation of large flat grains, XRD analysis showed a preferential c-axis orientation. The magnetic self-field J_c at 77 K was above 50 kA/cm². A strong dependence of the transport current, I_c, on the grain size was observed. The technology enables preparation of large-area thick superconducting films in a short processing time, is relatively cheap and appropriate for utilization in long-length RE-123 silver sheath wire production for commercial applications. These results led to two new Japanese patents.