Polarized Raman scattering in lanthanum gallogermanate glasses

摘要

Polarized Raman scattering has been used to charactyerize the structure of two series of lanthanum gallogermanate glasses with the composition xLa_2O_3-GeO_2-0.25Ga_2O_3 and 0.33La_2O_3-GeO_2-yGa_2O_3, where x, y = 0.2, 0.25, 0.33, and 0.5, We assigned the vibrational modes to different types of atomic motions in the glass network. No direct evidence of the six-fold coordinated (octahedral)germanium or gallium ions in the glass structure has been observed. The nature of the low frequency Raman peak - the so called Boson peak - is discussed in terms of the existing theories.