Neutron irradiation of Mg11B2: From the enhancement to the suppression of superconducting properties

Abstract

In this letter, we present the effect of neutron irradiation up to fluences of 1.4 × 1020 cm 2 on the superconducting properties of MgB2. In order to obtain a homogeneously distributed disorder, the experiment was carried out on bulk samples prepared with the 11B isotope. Up to fluences of 1018 cm-2, the critical temperature (Tc) is slightly diminished (36 K) and the superconducting properties are significantly improved; the upper critical field is increased from 13.5 T to 20.3 T at 12 K and the irreversibility field is doubled at 5 K. For the largest neutron fluence, Tc is suppressed down to 9.2 K and the superconducting properties come out strongly degraded. © 2005 American Institute of Physics.