Magnetization measurements on single crystals of $\mathrm{Y}{\mathrm{Ba}}_2{\mathrm{Cu}}_3{\mathrm{O}}_{7-\delta }$ show strong anisotropic flux pinning with critical magnetization current densities of 1.4×${10}^6$ A/${\mathrm{cm}}^2$. The critical magnetization currents fall sharply with temperature in both single-crystal and polycrystalline samples. The high critical magnetization current densities can be reduced by nearly two orders of magnitude by annealing.

• Received 10 June 1987

DOI:https://doi.org/10.1103/PhysRevB.36.4021