Thin superconducting films of single-phase YBa2-xSrxCu3O7-delta with v
alues of x up to 1.8 have been synthesized by means of pulsed-laser de
position (PLD). When increasing x from zero to 1.8, the zero resistanc
e temperature decreases from 91 K to 57 K; simultaneously the length o
f the c-axis decreases from 11.68 angstrom to 11.45 angstrom. The temp
erature dependence of the critical current density has been measured f
or materials with various values of x.