Melt-processed Gd–Ba–Cu–O superconductor with trapped field of 3 T at 77 K

Abstract

We fabricated a single-domain Gd–Ba–Cu–O bulk superconductor 65 mm in diameter andstudied the microstructure, superconducting and field-trapping properties. Melt-processing wasperformed under a controlled oxygen partial pressure of 1.0% using a precursor containingGd123 and Gd211 powders in a molar ratio of 2:1, with 0.5 wt% of Pt and 20 wt% ofAg2O added. The distribution of Ag and Gd211 particles was almost homogeneous. The additionof Ag was very effective in reducing the amount of cracking in the sample. Themaximum trapped magnetic field recorded was 3.05 T at 77 K. We also measuredthe trapped field between two Gd–Ba–Cu–O bulk samples in order to minimizethe demagnetizing effect and found that the trapped field reached 4.3 T at 77 K.