We study the effect of neutron irradiation on the critical current density Jc of isotopically pure polycrystalline Mg11B2 samples. For fluences in the range 10^17 - 10^18 cm^-2, Jc is enhanced and its dependence on magnetic field is significantly improved: we demonstrate that, in this regime, pointlike pinning centers are effectively introduced in the system proportionally to the neutron fluence. Instead, for larger fluences, a strong suppression of the critical temperature accompanied by a decrease of both the upper critical field Bc2 and Jc is found.
Enhanced flux pinning in neutron irradiated MgB2
I Pallecchi;V Braccini;C Fanciulli;C Ferdeghini;P Manfrinetti;M Vignolo;M Putti
2005
Abstract
We study the effect of neutron irradiation on the critical current density Jc of isotopically pure polycrystalline Mg11B2 samples. For fluences in the range 10^17 - 10^18 cm^-2, Jc is enhanced and its dependence on magnetic field is significantly improved: we demonstrate that, in this regime, pointlike pinning centers are effectively introduced in the system proportionally to the neutron fluence. Instead, for larger fluences, a strong suppression of the critical temperature accompanied by a decrease of both the upper critical field Bc2 and Jc is found.File in questo prodotto:
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