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 process, 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 volatility of Mg and, therefore, to ensure a high Mg content in the film. The films were deposited at temperatures ranging from room temperature to 300 degreesC followed by a low-pressure in situ annealing procedure. Various substrates have been used and diverse ways to increase the Mg content into the film were applied. The films show a sharp transition in the resistance and have a zero resistance transition temperature of 22-24 K. (C) 2001 American Institute of Physics.