Crystallization and Raman Spectra of Langasite-Type Na2CaGe6O14, Na2SrGe6O14 and Pb3Ga2Ge4O14 in Corresponding Glasses
We investigated the crystallization behavior of langasite-type phases in the stoichiometric corresponding glasses, i.e., Na2CaGe6O14, Na2SrGe6O14 and Pb3Ga2Ge4O14. The langasite-type phases singly were formed by heat-treatment in the glasses. Raman spectroscopy revealed the structural similarity on the scale of short-/medium-range order between the langasite-type phases and the corresponding glasses. Furthermore, we also examined the temperature dependence of second-harmonic (SH) intensity of the langasite-type phases. The SH-temperature curves exhibited an anomalous behavior, implying a structural change, e.g., isomorphous phase transition.
Tadashi Takenaka, Hajime Haneda, Kazumi Kato, Masasuke Takata and Kazuo Shinozaki
Y. Takahashi et al., "Crystallization and Raman Spectra of Langasite-Type Na2CaGe6O14, Na2SrGe6O14 and Pb3Ga2Ge4O14 in Corresponding Glasses", Key Engineering Materials, Vols. 421-422, pp. 213-216, 2010