GROWTH AND PROPERTIES OF YSR2CU2.75MO0.25O7-DELTA THIN-FILMS

We report on the epitaxial growth of YSr2Cu2.75Mo0.25O7-delta (YSCMO) thin films by pulsed laser ablation, and discuss the superconducting a nd normal state transport properties of microbridges patterned from su ch films. To investigate the dopant oxygen mobility of this material, we have used electrical biases applied at near room temperature to ind uce long range displacement of chain oxygen vacancies in these microbr idges, We find that with electromigration, the T-c of the microbridges can be raised to greater than or equal to 60 K. This transition tempe rature is higher than any previously achieved for this compound, inclu ding the T-c's achieved as result of extended very high pressure oxyge n anneals, or by high pressure in situ measurements. Micro-Raman spect roscopy measurements have been used to examine and characterize the ox ygen order in the film before and after electromigration. These measur ements indicate that, as suggested by the final T, achieved, a very hi gh degree of oxygenation and chain oxygen order can be induced in the microbridge by this process. Thus the as-grown properties of YSCMO app ear to be dominated by the low level of oxygenation and the low degree of oxygen homogeneity obtained by normal annealing processes.