CONTROLLING THE DOPANT INCORPORATION IN A-AXIS ORIENTED CO DOPED YBCOTHIN-FILMS

We studied the effects of Co doping (x = 0.22) on the intrinsic anisot ropic properties of in-plane aligned a-axis YBa2Cu3-xCoxO7-delta films pulsed laser deposited on (100) LaSrGaO4 substrates. We used x-ray-ab sorption fine structure analysis and resistivity data to determine the quality of Co incorporation. Higher deposition pressures provided fil ms with better Co dopant incorporation but smaller grain size. However at lower pressures proper Co incorporation can still be achieved by s lowing down the cooling process. For transport along the c- direction, Co dopant causes reduction in interlayer coupling as evidenced by an increase in interlayer coupling as evidenced by an increase in resisti ve anisotropy (rho(c)/rho(b)) with increasing level of Co incorporatio n. Co doping level of x = 0.22 effectively doubles the resistive aniso tropy of YBa2Cu3O7-delta films (from similar to 18 to similar to 40 at 100 K).