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 $\mathrm{in\; situ}$ two-step process, using the Mg–B plasma generated by pulsed-laser ablation. The target was composed of a mixture of Mg and ${\mathrm{MgB}}_{\mathrm{2}}$ 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 $\text{300\hspace{0.05em}°}\mathrm{C}$ followed by a low-pressure $\mathrm{in\; situ}$ 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.