Microstructure and Superconductive Properties of NdBa2Cu3Ox Superconductor Prepared by Floating zone Melting Method

摘要

Single crystalline NdBa2Cu3Ox (Nd123) superconductors with finely dispersed Nd4Ba2Cu2O10 (Nd422) particles were prepared by the floating zone melting method. Initial composition of the precursor material was Nd123 with addition of Nd422 or Pt. Unidirectional melting and solidification was carried out under low oxygen partial pressure atmosphere. Microstructure and existing phase identification of quenched samples were investigated by optical microscopy, backscattered SEM and XRD. Furthermore, superconductive properties were measured by SQUID. The results of SQUID measurements indicate that Tc of the Nd123 crystals os produced with oxygen heat treatment (773 K for 100 hours, air quench, 593 K for 200 hours, furnace cool) are about 90 K and Jc are about 2 x 10~4 A/cm~2 at 77 K. Addition of Pt did not contribute to the fine dispersion of Nd422 particles in Nd123 crystal. This is a noteworthy characteristic.