Irreversibility field and superconducting screening currents in EuBa<SUB>2</SUB>Cu<SUB>3</SUB>O<SUB>7</SUB>films

Measurements of the critical current density (Jc) and irreversibility field [Birr(T)] of epitaxial, c-axis-oriented EuBa2Cu3O7 (Eu-123) films are reported. The transition temperature (Tc), Jc, and Birr(T) of these pulsed-laser-deposited films depend critically on the growth temperature (TD), growth rate (Gr), and the oxygen partial pressure (pO2) during growth. As compared to YBa2Cu3O7, Eu-based films require lower Gr, higher pO2, and higher TD. These differences are attributed to the lower adatom mobility of Eu and its propensity for a 2+ oxidation state. The lattice mismatch between (100) LaAlO3 and the ab-plane of Eu-123 leads to an elongated c axis and some randomly oriented islands whose growth is truncated by epitaxial lateral overgrowth as the film thickness increases