Controlling the dopant incorporation in a-axis oriented Co doped YBCO thin films

We studied the effects of Co doping on the intrinsic anisotropic properties of aligned a-axis YBa/sub 2/Cu/sub 3-x/Co/sub x/O/sub 7-/spl delta// films pulsed laser deposited on (100) LaSrGaO/sub 4/ substrates We used X-ray-absorption fine structure analysis and resistivity data to determine the quality of Co incorporation. Higher deposition pressures provided with better Co dopant incorporation but smaller grain size. However at lower pressures Co incorporation can still be achieved by down the cooling process. For transport along the c-direction, Co dopant causes reduction interlayer coupling as evidenced by an increase resistive anisotropy (/spl rho//sub c///spl rho//sub b/) with increasing level of Co incorporation, Co doping level of x=0.22 effectively doubles the resistive anisotropy of YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// films (from -18 to -40 at 100 K).