Segregation in Fe substituted YBa2Cu3O7 films

Abstract

Understanding of the role played by the Cu(2)-O and the Cu(1)-O chains is crucial in the high Tc material YBa2Cu3O7 (YBCO). One approach has been to substitute other atoms such as Co, Fe, Ni and Zn for some of the Cu. A linear decrease in the Tc has been observed for several dopants, in particular for Fe substituted bulk samples, Tc⟶0 at 14-15%. Bulk sample studies show some variation in the amount of Tc suppression with concentration, possibly related to the method of materials preparation. The materials discussed here were prepared using the laser ablation technique. Successive ablations from a series of targets was used in order to achieve in principle a mixing on an atomic scale as the components are deposited about an atomic layer at a time. An XeCl laser deposition system was used, equiped with a computer controlled rotating target holder enclosed in a water-cooled shroud.