Raman spectra of R2O3 (R-rare earth) sesquioxides with C-type bixbyite crystal structure : a comparative study

• Autor(a) principal: Abrashev, Miroslav Vergilov
• Data de Publicação: 2014
• Outros Autores: Todorov, Neno Dimitrov, Geshev, Julian Penkov
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UFRGS
• Texto Completo: http://hdl.handle.net/10183/107858
• topic: Simetria cristalina; Dinamica de rede; Espectros raman; Compostos de európio; Compostos de érbio; Compostos de hólmio; Compostos de samário; Compostos de gadolínio; Compostos de ítrio; Compostos de escândio

Raman spectra of R2O3 (R—Sc, Er, Y, Ho, Gd, Eu, and Sm) powders with C-type bixbyite crystal structure are measured. With the help of these data and ones, previously published for other oxides from the same structural family, general dependencies of the frequencies of the Raman peaks on the cubic crystal unit cell parameter are constructed. Using these dependencies and knowing the symmetry of the peaks for one of the oxides, determined from previous single-crystal measurements, it is possible to find out the symmetry of the peaks from the spectra of all compounds. It was found that the frequency of the six lowest frequency peaks scales with the square root of the mass of the rare earth showing that mainly R ions take part in these vibrations. These results agree with performed here lattice dynamical calculations. The anomalous softening of the frequency of some peaks in the spectra of Eu2O3 is discussed.