Abstract:
C
6H
6-doped MgB
2 superconductor bulks were synthesized by ball milling subsequently solid state sintering using magnesium powder (Mg), boron powder (B) and benzene (C
6H
6) as raw materials. The effects of C
6H
6 doping on phase evolution, microstructure and the critical current density
Jc of MgB
2 were investigated. The results show that C
6H
6 doping has little effect on the formation temperature of MgB
2. C enters the lattice of MgB
2 by substitution for B, which makes the decreasing of lattice constant
a and the grain size refines gradually. C
6H
6-doped MgB
2 sample with molar fraction of 0.04 has relatively low superconducting transition critical temperature
Tc of 31 K, but exhibits the excellent
Jc. At high temperature 20 K and high magnetic density 2 T,
Jc remains at 3.6×10
4 A/cm
2, which is mainly due to hybrid flux pinning mechanism of grain boundary pinning and point pinning.