Effect of thermal strain on Jc and Tc in high density nano-SiC doped MgB2

The influences of lattice strain on the superconducting critical current density Jc and critical transition temperature Tc in pure MgB2 and a SiC-MgB2 composite made by the diffusion process are explored, based on the thermal expansion coefficients and the low temperature effects on Raman scattering. The strong thermal strain provides a strong flux pinning force for the supercurrents at the interfaces between SiC and MgB2. The high Tc of SiC-MgB2 is also discussed according to the expanded lattice and Raman characteristics.