INFLUENCE OF MICROSTRUCTURE ON THE PINNING PROPERTIES OF ND123

Melt-textured Nd123 samples are heat-treated at high temperatures in v arious atmospheres. For the sample prepared in 1% O-2-Ar, the decrease of J(c) was observed after the heat-treatment, eventhough there is no change in T-c. This could be explained by the agglomeration of Nd-ric h region (pinning center) during the heat treatment. On the other hand , the sample prepared in air showed the increase of T-c and J(c) by th e heat-treatment at 980 degrees C in low oxygen partial pressure (0.1% O-2-Ar), which could be understood by the partial melting of the Nd-r ich phase.