High-critical-current-density epitaxial films of SmBa2Cu3O7-x in high fields

The critical current density (J(c)) and irreversibility field (B-irr) of epitaxial SmBa2CU3O7-x (SmBCO) films are reported. The B-irr and J(c) of these films deposited on MgO(100) substrates by pulsed-laser deposition depend critically on the substrate temperature. The use of a thin SmBCO seed layer grown at a high substrate temperature enabled us to obtain fully c-axisoriented SmBCO films at relatively low temperatures, resulting in a high J(c) of 1.7 x 10(5) A/cm(2) of B parallel to c at 5 T and 77 K. This value is as high as that of the optimized NbTi superconducting wires achieved at 5 T and 4.2 K.