JOURNAL OF SUPERCONDUCTIVITY AND NOVEL MAGNETISM, cilt.24, ss.217-222, 2011 (SCI-Expanded)
We have produced the (BiPb)(2)V (x) Sr(2)Ca(3)Cu(4-y) Ti (y) O(12+delta) compounds for x=0.05 and y=0, 0.05, 0.10 and 0.20 by glass-ceramic method. The effects of vanadium adding and Ti doping on the structure have been investigated by electrical resistance, scanning electron micrographs (SEM), XRD patterns and magnetic hysteresis loop measurements. It has been found that the high-T (c) superconducting phase, (2223), is formed in the samples annealed at 845 degrees C for 185, with concentration x=y=0.05. However, with increasing Ti doping the (2223) phase transforms into the (2212) phase. We have observed no superconducting properties for x=0.05 and y=0.20 compound. It has completely transformed to semiconductor.
In addition, the critical current densities (J (c)), calculated from the hysteresis loop measurements by using Bean's critical state model are obtained for the samples in the same doping range. Our data have indicated that J (c) decreases with increasing temperature and Ti concentration.