Abstract
High quality Bi2Sr2CaCu2−xMoxOy (x = 0, 0.01 and 0.02) single crystals have been grown by a self-flux method in a horizontal temperature gradient and their flux pinning and irreversibility behaviour have been investigated. The irreversibility lines of the undoped and Mo-doped Bi2212 crystals have been greatly improved by reducing the anisotropy parameter γ. However, this improvement is much more pronounced for Mo-doped crystals than for the undoped ones. The peak effect of magnetization loops also changes with both Mo-doping and γ. The results provide strong evidence that the point defect pinning served by Mo is greatly enhanced when the anisotropy of the system is reduced.