Infrared spectra of nanometre granular zirconia

Citation
H. Zhang et al., Infrared spectra of nanometre granular zirconia, J PHYS-COND, 11(8), 1999, pp. 2035-2042
Citations number
20
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science
Journal title
JOURNAL OF PHYSICS-CONDENSED MATTER
ISSN journal
0953-8984 → ACNP
Volume
11
Issue
8
Year of publication
1999
Pages
2035 - 2042
Database
ISI
SICI code
0953-8984(19990301)11:8<2035:ISONGZ>2.0.ZU;2-9
Abstract
High-quality Fourier-transform infrared reflectance spectra of nanometre Zr O2 grains with particle sizes ranging from 5 nm to 120 nm have been recorde d at room temperature. The results show that, even for very small grain siz es (5-10 nm), the samples retain the main features of monoclinic symmetry, although the lowering of the crystal symmetry has led to the broadening of the infrared bands. Two surface phonons have been identified. The processes of strain removal above the 500 degrees C annealing temperature have been revealed by the appearance of two doublers at around 435 cm(-1) and 375 cm( -1); at the same time the particle sizes increase rapidly. As the particle size decreases, the doubly degenerate infrared-active modes, such as 2B(u) at 511 cm(-1) redshift while the non-degenerate modes, such as A(u) at 224 cm(-1), blueshift. This phenomenon is tentatively explained in terms of the internal-external classification of the lattice vibrations.