Scaling behaviour of Al-doped YBCO laser ablated thin films

Magnetization data of Al-doped YBCO laser ablated thin films were used to c alculate the critical temperature and magnetization of the sample. These we re found to be greatly dependent on the dopant concentration. Magnetization curves of samples with different Al concentrations but at the same tempera ture exhibit similar field dependences with no anomalous behaviour detected . The critical current density J(c), extracted from the width of magnetizat ion curve, scaled as J(c) = J(c)(0)(1 - T/T-c)(n), with n similar to 2.3. T he temperature-dependent pinning force for samples with different Al concen tration scaled well as F-p = F-h0(T)h(p)(1 - h)(q), where h is the reduced field and p and q are parameters of the order of 0.5 and 2, respectively. T his type of scaling is in good agreement with the flux line lattice shear m odel. F-p shows a peak behaviour that scales as a power law of H-max (F-p p roportional to H-max(n)).