Enhancement of Flux Pinning in Neutron Irradiated MgB₂ Superconductor

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m-H loops for virgin and neutron irradiated bulk and powder samples of MgB₂ were measured in the temperature range 5-30 K in magnetic field B<= 1 T. The irradiation at thermal neutron fluences 9*10¹³ and 4.5*10¹⁴ cm⁻² caused very small enhancement of m-H loops at lower temperatures (T<20 K), whereas the effect at high temperatures was unclear due to difficulty in achieving exactly the same measurement temperature prior and after irradiation. However, the irradiation at 4.5*10¹⁵ cm⁻² produced clear enhancement of m-H loops (hence Jc) at all investigated temperatures, which provides the evidence for the enhancement of flux pinning in MgB₂ due to ion tracks resulting from n+¹⁰B reaction. The potential of this technique for the enhancement of flux pinning in high temperature superconductors is briefly discussed.