Raman scattering measurements were performed to investigate optical modes of scheelite-type double molybdates XY(MoO4)2 (X=Li, Na and Y = La, Nd). In the polarized Raman scattering measurements, we have found four modes in NaLa(MoO4)2, one in low frequency region (with Bg symmetry) and three in high frequency region, which are missing in the previous observation by Ramakrishnan. The scattered light by the high-frequency modes does not show clear polarization characteristics. By the drastic modification of these modes with changing the proportion x of NaxLa(4–x)/3(MoO4)2, we concluded that the newly found high-frequency modes result from the local deformation caused by the random positioning of the X+ and Y3+ ions.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)