Superconducting Mg-B films by pulsed-laser deposition in an in situ two-step process using multicomponent targets

Superconducting thin films have been prepared in an in situ two-step proces s, using the Mg-B plasma generated by pulsed-laser ablation. The target was composed of a mixture of Mg and MgB2 powders to compensate for the volatil ity of Mg and, therefore, to ensure a high Mg content in the film. The film s were deposited at temperatures ranging from room temperature to 300 degre esC followed by a low-pressure in situ annealing procedure. Various substra tes have been used and diverse ways to increase the Mg content into the fil m were applied. The films show a sharp transition in the resistance and hav e a zero resistance transition temperature of 22-24 K. (C) 2001 American In stitute of Physics.