Enhanced Jc of B-rich and SiC doped MgB2 tapes fabricated by a modified in-situ PIT method with two stage heat treatment

Abstract

B-rich and SiC doped MgB2 tapes were fabricated by a modified in-situ PIT method with two stage heat treatment. B composition ratio and an amount of SiC doping were systematically changed. The effect of pre-heating and final heating conditions on Jc-B properties was also studied. Mean grain size of MgB2.8 specimens reduced to about 100 nm by increasing SiC doping 5.7%. In low fields Jc slightly increased for a little SiC doped specimens. On the other hand, in high fields, Jc obviously increased with increasing SiC doping. Maximum Jc reached 1.8×103 A/cm2 at 3 T, 20 K for MgB2.8 specimen doped SiC 5.7 mol%. Birr also increased with increasing SiC doping. Jc systematically increased with the decrease of temperature of pre-heat treatment. In contrast Jc systematically increased with the increase of temperature of final heat treatment. Best Jc of 8.6×104 A/cm2 at 20 K, 0 T was achieved for specimen with 700 °C for 5 hours + 800 °C for 1 hour heating. Birr tended to increase with the increase of Jc.