Enhanced flux pinning in neutron irradiated MgB2

Abstract

We study the effect of neutron irradiation on the critical current density Jc of isotopically pure polycrystalline MgB211 samples. For fluences in the range 1017-1018cm-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. © 2005 The American Physical Society.