Critical currents of OCMG processed Nd123 crystals

Critical current densities of Nd123 crystals flux grown by the oxygen-controlled-melt-growth (OCMG) process have been studied with DC magnetization measurements, The superconducting transition temperature (T-c) of the Nd123 crystal flux grown in 0.1%O-2-Ar gas was 94 K with the applied field of 10 Oe parallel to the c-axis. The sample was found to be homogeneous without weakly linked regions through magneto-optical measurements. DC magnetization-hysteresis curves measured with a SQUID magnetometer exhibited a peak effect at various temperatures above 70 K. The peak effect is attributable to field-induced pinning by finely distributed low-T-c phases. The sample exhibited high critical current density (J(c)) values of 4 x 10(4) A/cm(2) in 2 T and over 1 X 10(4) A/cm(2) in 4 T at 77 K for Fields parallel to the c-axis.