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

Description

In this letter, we present the effect of neutron irradiation up to fluences of 1.431020 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 sTcd is slightly diminished s36 Kd and the superconducting properties are significantly improved; the upper critical field is increased from 13.5 T to 20.3 T at12 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.

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