ROLE OF SILVER DOPING IN OXYGEN INCORPORATION OF OXIDE THIN-FILM

A distinctive characteristic of silver in oxygen incorporation of oxid e thin films during pulsed laser ablation has been discovered. Optical emission spectroscopy studies of laser-induced plume of Ag-target ind icates the presence of AgO species whose concentration increases with an increase in oxygen partial pressure. The formation of AgO in laser- plume has been found to be very useful for the realization of high tem perature superconducting YBa2Cu3O7-delta (YBCO) and giant magnetoresis tive La0.7MnO3-delta (LMO) thin films with dramatically superior quali ty if the target materials contained a small amount of silver. The imp rovement in the quality of these films is brought about by the supply of atomic oxygen to oxide lattices during their formation. This become s possible due to the fact that Ag, after it is ablated with other con stituent materials in the target, gets moderately oxidized in an oxyge n atmosphere and the oxidized species dissociate back into Ag and nasc ent O at the substrate surface. The nascent oxygen is very highly reac tive and is easily assimilated into the lattice of these compounds. (C ) 1997 Elsevier Science S.A.