Scanning tunneling microscopy studies of high Jc NEG123 crystals

We have performed ultrahigh vacuum scanning tunneling microscopy measurements at room temperature on (Nd0.33Eu0.38Gd0.28)Ba2Cu3Oy (NEG123) crystals grown by an oxygen controlled melt growth process. Two characteristic nanostructures, namely, modulation and island structures have been observed on a cleaved surface of the NEG123 with high J(c) and high irreversible field H-irr higher than 10 T at 77 K. These structures may be associated with an element substitution and the good J(c)-B property. (C) 2003 Elsevier Science B.V. All rights reserved.