Irreversibility field and flux pinning in MgB2with and without SiC additions

The critical current density ( J c ) was measured at 4.2 K for MgB 2 strands with and without SiC additions. In some cases measurements were performed on long (1 m) samples wound on barrels, the transport results being compared to the results of magnetic measurements. Most measurements were performed on short samples in fields of up to 18 T. It was found that in situ processed strands with 10% SiC additions heat treated at 700–800 °C showed improved irreversibility fields ( H r ) and bulk pinning strengths ( F p ) as compared to control samples; an increase in H r of 1.5 T was noted. Heat treatment to 900 °C gave even larger improvements, with H r reaching 18 T and F p values maximizing at 20 GN m −3 .