Uranium Doping and Thermal Neutron Irradiation Flux Pinning Effects in MgB<tex>$_2$</tex>

Abstract

The U/n method is a well-established means of improving flux pinning and critical current performance in cuprate superconductors. The method involves the doping of the superconductor with 235 U followed by irradiation with thermal neutrons to promote fission. The resultant columnar damage tracks produced by the energetic fission products pin flux vortices and improve critical current performance in magnetic fields. No such improvement could be observed when the U/n method was applied to MgB 2 superconductor. No fission tracks could be observed in TEM, even for samples that were irradiated at the highest fluence. Gamma-ray spectroscopy indicated that fission had occurred in the expected way.

Improvement of critical current density of MgB2 bulk superconductor processed by Spark Plasma Sintering

“…As a consequence, to obtain high trapped fields it is necessary to make large superconducting bulks comprising effective pinning sites. For J c enhancement, different strategies have been investigated including irradiation, 16‐18 chemical doping, 19‐21 or substitution, 22 particle size refinement by mechanical ball milling 23 and other techniques. Among various chemical dopants, carbon was one of the most effective choice.…”

Enhanced critical current density of in situ processed MgB2 bulk superconductors with MgB4 additions

“…Small defects such as vacancies and cavities can be formed in the superconducting matrix through particle irradiation [15][16][17][18][19][20] . As a result of the defect formation, the J c at * Corresponding author: cjkim2@kaeri.re.kr the magnetic fields of the particle-irradiated MgB 2 was much higher than that of MgB 2 with no irradiation [21,22]. Along with the physical method, the J c of MgB 2 can be increased by the doping of chemical species such as silicon carbide [23], carbon-related materials [24], and other fine impurity phases [25].…”