2005/04/27 by T Sakuntala, T. Sakuntala, A. Bharathi +9 · 10 citations
Materials Science · Physics and Astronomy · #Analytical Chemistry (journal) #Boron and Carbon Nanomaterials Research #Coupling (piping) #Line (geometry) #Line width #Phonon #Raman scattering #Raman spectroscopy #Superconductivity in MgB2 and Alloys #Thermal Expansion and Ionic Conductivity #X-ray Raman scattering #cond-mat.mtrl-sci #cond-mat.supr-con
paper · pdf · doi:10.1088/0953-8984/17/21/021
published in Journal of Physics Condensed Matter 17(21), 3285-3292 (IOP Publishing) · PDF format; containing text and figures. accepted for publication in Journal of Physics Condensed Matter
arxiv created 2005/04/27 · openalex publication_date 2005/05/13 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Room temperature Raman scattering measurements have been carried out on well characterized samples of MgB2-xCx. The Raman line corresponding to the E2g phonon mode shows progressive hardening from 620 cm-1 in pristine MgB2 to 775 cm-1 in the sample with carbon fraction x=0.2. The corresponding line width on the other hand, increases from a value of about 220 cm-1 to 286 cm-1 in samples with x = 0.1, beyond which it decreases to a value 167 cm-1 for x=0.2. From the average mode frequency and the line width obtained from Raman measurements and taking the values of N(0) obtained from the calculated variation in s hole density of states in MgB2-xCx, the electron phonon coupling strength to the E2g phonon, l2g, is evaluated using Allen’s formula. This remains large for low C fraction, but shows rapid decrease for x > 0.10. Using this value of l2g appropriately weighted, TC is obtained from McMillan’s equation. These values are in good agreement with the experimentally measured TC variation in MgB2-xCx.