Spatially resolved measurements of critical parameters in superconducting filaments by laser scanning technique

We present an experimental study of local transport properties of superconducting filaments by means of low temperature scanning laser microscopy (LTSLM). A novel theoretical model that treats the laser-beam-induced voltage response is proposed and applied to analyze the measured data. The method of LTSLM allows to visualize the local inhomogeneities in individual filaments extracted from (Bi,Pb)/sub 2/Sr/sub 2/Ca/sub 2/Cu/sub 3/O/sub 10+x//Ag tapes. Using the proposed theoretical analysis we extract the spatial distributions of the critical currents and critical temperatures over the sample. Tile data obtained by LTLSM show good agreement with standard non-local transport measurements. Using autocorrelation analysis of the voltage response, the characteristic length of the critical current variation is retrieved for filaments that belong to different parts of the tape.