Potentials of RE-Ba₂Cu₃O_y in the silver base technology

With the aim to develop low cost, high performance superconducting thick films, we tested a new method, starting from a mixture of Er₂BaO₄, BaCuO₂, and CuO in the stoichiometric Er-123 ratio. Thick films were prepared by the screen printing technique, spreading the mixture paste on silver and MgO single-crystalline substrates processed then in Ar-1% O₂ atmosphere. Using a double-step annealing process, we obtained good quality Er-123 thick films on silver substrates, with T_c (onset) 92 K and transition width <1.5 K. Formation of large flat grains was observed by scanning electron microscope. Transmission electron microscopy observations showed clean and sharp interfaces between 123 phase and silver substrate.