Growth and properties of YSr/sub 2/Cu/sub 2.75/Mo/sub 0.25/O/sub 7-/spl delta// thin films

We report on the epitaxial growth of YSr/sub 2/Cu/sub 2.75/Mo/sub 0.25/O/sub 7-/spl delta// (YSCMO) thin films by pulsed laser ablation, and discuss the superconducting find normal state transport properties of microbridges patterned from such films. To investigate the dopant oxygen mobility of this material, we have used electrical biases applied at near room temperature to induce long range displacement of chain oxygen vacancies in these microbridges. We find that with electromigration, the T/sub c/ of the microbridges can be raised to |60 K. This transition temperature is higher than any previously achieved for this compound, including the T/sub c/´s achieved. As result of extended very high pressure oxygen anneals, or by high pressure in situ measurements. Micro-Raman spectroscopy measurements have been used to examine and characterize the oxygen order in the film before and After electromigration. These measurements indicate that, as suggested by the final T/sub c/ achieved, a very high degree of oxygenation and chain oxygen order can be induced in the microbridge by this process. Thus the as-grown properties of YSCMO appear to be dominated by the low level of oxygenation and the low degree of oxygen homogeneity obtained by normal annealing processes.