Neutron Irradiation of Mg11B2 : From the Enhancement to the Suppression of Superconducting Properties

TL;DR

This study investigates how neutron irradiation affects MgB2 superconductors, revealing enhancements at low fluences and suppression at higher fluences, with detailed changes in critical temperature and magnetic fields.

Contribution

It provides the first detailed analysis of neutron irradiation effects on MgB2 using homogeneous isotope-enriched samples, highlighting both enhancement and suppression of superconducting properties.

Findings

Superconducting properties improve at low neutron fluences.

Critical temperature decreases with higher neutron fluences.

Upper critical field increases significantly at moderate fluences.

Abstract

In this letter we present the effect of neutron irradiation up to fluences of 3.9 1019 n/cm2 on the superconducting properties of MgB2. In order to obtain a disorder structure homogeneously distributed, the experiment was carried out on bulk samples prepared with the 11B isotope. Up to fluences of 1018 n/cm2 the critical temperature 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 larger neutron fluences the critical temperature is suppressed down to 12 K and the superconducting properties come out strongly degraded.