Magnetoelectric properties of MgB2 superconductor by SiC doping

Effect of SiC, as carbon source doping, by diffusion method on the lattice parameter, critical temperature (T
_c
) and critical current density (J
_c
) has been studied. The broadening of full width at half maximum (FWHM) values in XRD patterns with increasing of the doping level indicates smaller grains and imperfect MgB
₂
crystallinity, whereas the carbon substitution into the boron site was confirmed by the shrinkage of the lattice parameter a. Despite of lower T
_c
's, J
_c
s of the doped samples are higher than the undoped sample over 4 T at 20 K and over 7 T at 5 K, respectively. MgB
₂
with the 10 % of SiC doping showed the highest J
_c
with the value of 10
⁵
A/cm
²
at 5 K and 4 T while the 2.5% SiC doped sample showed 7 factor of J
_c
enhancement compared to pristine sample at 20 K and 4.5 T. J
_c
enhancement by different doping level at respective temperature suggests, impurities such as Mg
₂
Si, MgB
₂
C
₂
and MgO play a significant role in 20 K while carbon substitution effect dominances the flux pinning in 5 K. Our results also demonstrate that flux pinning and the J
_c
can be tailored for various applications depending on the operating temperature and external magnetic field.