Crystallinity and transport properties in Bi2Sr2Ca1-xPrxCu2Oy single crystals

Bi2Sr2Ca1-xPrxCu2Oy (x ranging from 0 to 0.5) single crystals have been grown by a self-flux method from Bi-rich melts. The crystals obtained manifest slim and plate-like shapes. The crystallinity is studied by x-ray diffraction. The x-ray θ-scanning rocking curve shows that the slim crystal has perfect crystal structure while the plate-like crystal is mosaic along the c-axis. The in-plane resistivity ρab(T) has been measured for crystals with different Pr doping levels. Tc is suppressed gradually upon doping while the residual resistivity increases strongly. A superconductor-insulator transition is observed which is attributed to the tetragonal-orthorhombic phase transition when the Pr content reaches about 0.5. The effect of oxygen doping on in-plane resistivity ρab(T) is also studied for x = 0.22 and 0.40 crystals.