Tl₂Ba₂CaCu₂O_8-x superconducting films deposited by aerosol and their hysteretic ac losses

ac susceptibility measurements have been performed on Tl₂Ba₂CaCu₂O_8-x superconducting films. The films were grown in two steps: first Ba-Ca-Cu-Ag-O precursor films have been prepared by spraying an aerosol on MgO substrates and the Tl was then subsequently introduced by diffusion into the precursor films. The most favourable preparation conditions have been determined by comparing the structural and magnetic properties of the films. A detailed study of the ac susceptibility shows that the ac losses are due to intragrain bulk hysteretic pinning eventhough small geometrical barriers contributions could also be observed.