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Micro-Raman scattering investigation of MgB2 and RB2 (R=Al, Mn, Nb and Ti)

N. Ogita·T. Kariya·K. Hiraoka·J. Nagamatsu·T. Muranaka·H. Takagiwa·J. Akimitsu·M. Udagawa
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Abstract

Phonon spectra have been investigated by micro-Raman scattering from 290 to 20K. New peaks at 500 and 674 cm-1 appear below 250K in MgB2. These peaks are explained by the Fermi resonance, where Raman-active E2g intereacts with the overtone of E1u due to anhamonicity. Raman spectra of the isostructural RB2 (R=Al, Mn, Nb and Ti) have been also measured at 290K. The line width of E2g phonon of the superconductor MgB2 and NbB2 shows the broader than that of the non-superconductors. It is found that the anharmonicity of phonons is important for the superconductivity for MgB2.

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N. Ogita, T. Kariya, K. Hiraoka, J. Nagamatsu, T. Muranaka, H. Takagiwa, J. Akimitsu, M. Udagawa. 2001-06-08. Micro-Raman scattering investigation of MgB2 and RB2 (R=Al, Mn, Nb and Ti). https://arxiv.org/abs/cond-mat/0106147

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