Effects of neutron irradiation on polycrystalline Mg11B2

Abstract

We studied the influence of the disorder introduced in polycrystalline MgB2 samples by neutron irradiation. To circumvent self shielding effects due to the strong interaction between thermal neutrons and 10B we employed isotopically enriched 11B which contains 40 times less 10B than natural B. The comparison of electrical and structural properties of different series of samples irradiated in different neutron sources, also using Cd shields, allowed us to conclude that, despite the low 10B content, the main damage mechanisms are caused by thermal neutrons, whereas fast neutrons play a minor role. Irradiation leads to an improvement in both upper critical field and critical current density for an exposure level in the range 1-2x1018 cm-2. With increasing fluence the superconducting properties are depressed. An in-depth analysis of the critical field and current density behaviour has been carried out to identify what scattering and pinning mechanisms come into play. Finally the correlation between some characteristic lengths and the transition widths is analysed.

22 pages, 12 figures. In press on Phys. Rev. B

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• Systematic study of disorder induced by neutron irradiation in MgB2 thin films
• Point-contact spectroscopy in neutron-irradiated Mg^{11}B_2
• Intraband versus interband scattering rate effects in neutron irradiated MgB2
• High-energy ball milling and synthesi temperature study to improve superconducting properties of MgB2 ex-situ tapes and wires
• Enhanced upper critical field in Co-doped Ba122 superconductors by lattice defect tuning
• Connectivity and Critical Currents in Polycrystalline MgB2
• Hydrostatic pressure induced transition from δTc to δl pinning mechanism in MgB2
• Strongly Enhanced Current-Carrying Performance in MgB2 Tape Conductors by Novel C60 Doping
• Point-contact Andreev-reflection spectroscopy in segregation-free Mg_{1-x}Al_{x}B_2 single crystals up to x=0.32
• Neutron Irradiation of Sm-1111
• Influence of carbon-ion irradiation on the superconducting critical properties of MgB${}_2$ thin films
• Depinning frequency in a heavily neutron-irradiated MgB2 sample
• Effect of $\alpha$-particle irradiation on a NdFeAs(O,F) thin film
• Application prospects of MgB${}_2$ in view of its basic properties
• Experimental confirmation of the low B isotope coefficient in MgB2
• Microwave surface resistance of pristine and neutron-irradiated MgB2 samples in magnetic field
• Band filling and disorder effects on the normal state thermoelectric behavior in MgB2