Enhancement of critical current density in Gd123 bulk superconductor doped with magnetic powder

We studied the materials processing to grow high performance magnet with doping of magnetic powder as candidature of pinning centers. The magnetic powder was doped into Gd123 matrix and grew into single domain bulk in air. With doping magnetic powder in Gd123 bulk superconductors, the flux pinning was enhanced and the underlying mechanism was discussed. The experimental results showed that suitable amount of magnetic powder inclusion can be effect as pinning center to enhance the Jc of the bulk both in low magnetic field and high magnetic field, which was different from the bulk doped with paramagnetic nano-scaled particles. The Tc of the bulk was suppressed obviously with the content of the magnetic powder increasing, form 93.0 K without doping decrease to 90.5 K with 0.12 wt.% doping. This is consistent with that the magnetic impurities generally suppress superconductivity. We report the detailed results from the viewpoint of practical application to increase the integrated flux trapped inside the bulk.