TITLE:
Flux Pinning in Y- and Ag-Doped MgB2
AUTHORS:
Jack Dyson, Daniele Rinaldi, Gianni Barucca, Gianni Albertini, Simone Sprio, Anna Tampieri
KEYWORDS:
Flux Pinning, AC Magnetic Measurements, Critical Current, Yttrium-Doping, Silver-Doping, MgB2 Superconductors, Transmission Electron Microscopy, X-Ray Diffraction
JOURNAL NAME:
Advances in Materials Physics and Chemistry,
Vol.5 No.10,
October
28,
2015
ABSTRACT: High temperature superconductor research is presently concentrated upon
the flux pinning properties of the Abrikosov lattice of the mixed-mode superconducting
phase. The temperature thermal fluctuations, current and magnetic field unpin
the flux vortices and so cause electromagnetic resistivity in high temperature
superconductors. Materials with higher vortex pinning exhibit less resistivity
and are more attractive for industrial uses. In the present article, we
measured and correlated the pinning flux energy barrier, determined by AC magnetic
measurements, and transmission electron microscopy measurements to the
critical current Jc in
Yttrium- and Silver-doped MgB2 superconductors. The energy of the
flux vortex was evaluated as a function of the magnetic field. The energy
barrier curves suggest an optimal doping level to occur in doped materials.
This result only depends on the optimal size and distribution of precipitates,
and not on their chemical composition. The energy barriers have been compared
with that of undoped MgB2 in literature.