Vibrational properties of LaPO4 nanoparticles in mid- and far-infrared domain

Abstract

Nanopowders of LaPO4 have been grown by sedimentation-micellar method. As-prepared LaPO4 nanoparticles with the average grain size of about 8 nm have a single-phase hydrated hexagonal structure. After thermal annealing at 600 and 800 °C, the average size of nanoparticles increases up to ∼35 and ∼50 nm, respectively, and the structure transforms into single-phase monoclinic. IR spectra of LaPO4 nanoparticles of different size were investigated in the wide range of wavenumbers from 130 to 5000 cm−1 in the 20–300 K temperature region. Differences between IR spectra of the bulk material and nanoparticles as well as the temperature behavior of the vibrational properties are discussed.

Effects of pH value on growth morphology of LaPO4 nanocrystals: investigated from experiment and theoretical calculations

“…The changes in split size and small peak shifts could be observed in m 1 , m 3 and m 4 due to the band splitting and energy shifts. These analyses of FT-IR had a good agreement with the work reported [22].…”

“…Overall, these spectra curves had three main groups of vibrational bands. The FIR spectrum and MIR domain of monoclinic LaPO 4 were investigated by Savchyn et al [22] including the temperature and size dependence. Basing on that reference, it was easy to obtain the assignment of those vibrational bands as shown in figure. With the decreasing in the nanorods size, the spectra exhibit lower resonant frequency and better resolution of the vibrational bands.…”

Plasma spray-deposited lanthanum phosphate coatings for protection against molten uranium corrosion

“…The spectra showed absorption bands between 1100-900 cm −1 and 600-450 cm −1 , which were attributed to the respective symmetric and asymmetric P-O stretching vibrations. The presence of four bands as two doublets in the ν4 region at 530, 558 and 572, 612 cm −1 and ν3 region at 951, 990, 1037, and 1091 cm −1 are characteristic of the vibrations of the phosphate groups in the monoclinic structure of monazite-type LaPO 4 [25,26]. The results of Raman and FTIR spectra further corroborate the findings of X-ray diffraction and confirm the stability of LaPO 4 phase even after plasma melting.…”

Synchrotron-based far-infrared spectroscopy of nickel tungstate

“…Therefore, they are intensively used nowadays in infrared (IR) spectroscopy to probe vibrational properties of single crystalline [1,2], microcrystaline [2,3] and nanocrystalline materials [4][5][6][7]. Besides that infrared spectrum can contain information on magnetic excitations, which were observed, for example, in antiferromagnetic metal oxides as CoO, NiO and solid solutions Ni c Mg 1-c O and Co c Mg 1-c O [2,8].…”