Abstract
We have studied the superconducting properties of Nd(Ba1-xNdx)2Cu3O7-δ (Nd123, x≈0.1) single crystals grown by the traveling-solvent floating-zone method under 0.1% O2 in Ar atmosphere. An anomalous peak effect in the magnetization hysteresis (M-B) loop is observed in the Nd123 single crystals as well as in the Nd 123 bulk crystals prepared by the oxygen-controlledmelt-growth (OCMG) method. The critical current density (Jc) of the Nd123 single crystals is 70, 600 A/cm2 in 1.0T at 77K for the applied field perpendicular to the ab-plane. The existence of Nd and Ba composition variation in the matrix of Nd123 crystals is observed by an analytical TEM equipped with a cold field-emission gun. The high Jc value of the Nd123 single crystals in the applied field is explained by the field-induced pinning centers caused by the Nd-Ba substitutions in the Nd123 matrix.
