FT Raman Spectroscopy of Some Metal Hexaborides

✍ Scribed by R. Schmechel; H. Werheit; Yu.B. Paderno

• Publisher: Elsevier Science
• Year: 1997
• Tongue: English
• Weight: 262 KB
• Volume: 133
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.1997.7453

✦ Synopsis

Fourier-transform Raman (FT) spectra of single-crystal LaB 6 and SmB 6 and of sintered EuB 6؊X C X (X+0.1) were measured at room temperature. For excitation a Nd:YAG laser with about 2 W irradiation power was used. The spectra exhibited many more details of the phonon densities of states than those obtained with conventional Raman spectroscopy by other authors. In particular two low-energy peaks were found at 104 and 204 cm ؊1 , which can be easily attributed to the acoustical and the lowest optical branches. The FT Raman spectra of LaB 6 agree well with the phonon densities of states determined by other experimental methods and theoretical calculation, while for SmB 6 a considerable softening of the optical modes is observed, which is probably due to nonlinear effects in consequence of the high excitation power used in the FT Raman spectrometer.