The preparation of the polycrystalline NdBa2Cu3O7-δ superconductor using Ba2Cu3O5+x as a precursor has been studied. Ba2Cu3O5+x was prepared by the sol-gel process using metal acetates as starting materials, tartaric acid as an chelating reagent and water as solvent. The gel was heated at 780°C for 60 h in O2 to form the Ba2Cu3O5+x. precursor. The value of x in Ba2Cu3O5+x was determined to be 0.5; that is, copper was in a highly oxidized state over +2. NdBa2Cu3O7-δ was obtained by the solid-state reaction between Nd2O3 and Ba2Cu3O5+x heated at 900°C for 20 h in N2. Although the sample did not undergo post-anneal in oxygen, it showed good superconducting properties; Tc of 94 K and the intragranular Jc of 3.7 × 105 A/cm2 under a field of 50 kOe at 20 K. The advantage of using Ba2Cu3O5+x is considered to be its sufficient amount of oxygen as well as prevention of the Nd3+/Ba2+ substitution.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Energy Engineering and Power Technology
- Electrical and Electronic Engineering