Raman Studies in MgB2-xCx

Raman scattering measurements have been carried out in MgB2-xCx for x=0.0 -0.30. The broad Raman band around 600cm-1 range, which corresponds to the E2g mode in MgB2 is seen to narrow and reduce in intensity with increasing carbon content. For x>0.15, new set of bands appear at 1200 cm-1 possibly arising from the B-C, E2g modes. The decrease in Tc with carbon substitution seems to correlate with this change over.