Superconducting transitions of Nd-based 123 superconductors in fields up to 7 T

Superconducting transitions were measured in field-cooled cooling and field-cooled warming modes in external magnetic fields ranging between 1 mT and 7 T on various Nd-based 123 superconductors (NdBa₂Cu₃O_7- single crystals and melt-processed samples, and melt-textured ternary compounds). Most of the Nd-based superconductors investigated exhibit a two-step transition when being cooled or warmed in fields larger than 4 T. We ascribe this effect to the presence of an Nd-rich phase providing a spatial scatter of the transition temperature, T_c, throughout the sample.