Resonance Raman spectroscopy of NdAlO3 single-crystal fibers grown by the laser-heated pedestal growth technique

Fabrication of Ln2Zr2O7 Fluorite and LnAlO3 Perovskite (Ln = La, Nd, Sm) Compounds to Catalyze the OCM Reaction: On the Temperature-Induced Phase Transformation and Oxygen Vacancy

“…The Raman peak at 241 cm –1 is assigned to the A 1g mode, corresponding to the rotation of AlO 6 octahedra, whereas the peaks at 162 and 508 cm –1 are attributed to the E g mode, corresponding to the bending vibration of the Nd–O bond . Another E g mode observed at 590 cm –1 can be assigned to the out-of-phase stretching vibration of oxygens. − For SmAlO 3 , the Raman peaks at 139, 174, 191, 292, 339, 386, and 506 cm –1 can be ascribed to the active modes of A g , B 2g , B 2g , A g , A g , B 2g , and B 3g in the orthorhombic symmetry of the crystal phase with the P bnm space group, respectively . The lattice parameters were calculated from XRD in Table , which match well to their phase structures.…”

“…47,48 For NdAlO 3 , the Raman peaks at 162, 241, 507, and 591 cm −1 are also assignable to the rhombohedral symmetry of the phase structure with the R-3c space group. The Raman peak at 241 cm −1 is assigned to the A 1g mode, corresponding to the rotation of AlO 6 octahedra, 49 whereas the peaks at 162 and 508 cm −1 are attributed to the E g mode, corresponding to the bending vibration of the Nd−O bond. 49 Another E g mode observed at 590 cm −1 can be assigned to the out-of-phase stretching vibration of oxygens.…”

First-principles calculations and Raman scattering evidence for local symmetry lowering in rhombohedral ilmenite: temperature- and pressure-dependent studies

“…Indeed, one and two Lorentzian functions were included during the fitting to adjust the bands in (g) and (h), respectively. Additional Raman modes may be a signal of local symmetry lowering at low temperatures [60] or even lattice distortions at room temperature induced by occupational disorder [61,62]. In general, the interatomic distance tends to decrease when temperature decreases, leading to local distortion that lowers the unit cell symmetry.…”

The effects of pressure on the lattice of the rare-earth-based perovskite-type oxides SmAlO3 and NdAlO3

“…Major peaks can be assigned as follows: the band at 240 cm −1 of the A 1g mode is related to the rotation of the O octahedra; the two bands at 163 and 513 cm −1 of the E g mode are associated with the vibration of the Nd atoms and the bending vibration of O atoms, respectively; the band at 590 cm −1 of the E g mode is related to the out of phase stretching vibration of O atoms [54][55][56]. The forbidden Raman modes observed at around 380 and 700 cm −1 may be related to the vibrations of the Nd 3+ ions [56]. Figure 8(b) summarizes the Raman shifts that occur with changes in pressure.…”