EFFECTS OF THE C-AXIS RESISTIVE TRANSITION WIDTH ON THE SECONDARY VOLTAGE OF BI2SR2CACU2O8-Y

We have recently reported six-contact-lead measurements of the zero-fi eld resistive transition of Bi2Sr2CaCu2O8-y single crystals which show ed that the secondary voltage, obtained with a ''flux-transformer'' el ectrode geometry, exhibited a peak near the transition. To investigate the effects of sample inhomogeneities on this structure, we report he re measurements on two crystals of different quality, as evidenced by the measured c-axis transition widths of 0.6 K and 2.0 K, respectively . Both samples yield a secondary voltage peak near the transition, wit h the higher quality sample displaying a larger peak. We compare the r esults to a ''resistor'' model, representing the samples as anisotropi c resistive media, and find good agreement with the data above the tra nsition(T greater-than-or-equal-to T(c)c). Below the transition, howev er, the model does not reproduce the behavior observed in both crystal s.