Temperature-dependent EXAFS analysis of embedded Pt nanocrystals
No Thumbnail Available
Date
2009-04-15
Journal Title
Journal ISSN
Volume Title
Publisher
Institute of Physics
Abstract
The vibrational and thermal properties of embedded Pt nanocrystals (NCs) have been investigated with temperature-dependent extended x-ray absorption fine structure (EXAFS) spectroscopy. NCs of diameter 1.8-7.4 nm produced by ion implantation in amorphous SiO2 were analysed over the temperature range 20-295 K. An increase in Einstein temperature (similar to 194 K) relative to that of a Pt standard (similar to 179 K) was evident for the smallest NCs while those larger than similar to 2.0 nm exhibited values comparable to bulk material. Similarly, the thermal expansion of interatomic distances was lowest for small NCs. While the amorphous SiO2 matrix restricted the thermal expansion of interatomic distances, it did not have a significant influence on the mean vibrational frequency of embedded Pt NCs. Instead, the latter was governed by finite-size effects or, specifically, capillary pressure. © 2009, Institute of Physics
Description
Keywords
Absorption, Thermal expansion, Ion implantation, Vibrational states, Silica, Platinum
Citation
Giulian, R., Araujo, L. L., Kluth, P., Sprouster, D. J., Schnohr, C. S., Foran, G. J., & Ridgway, M. C. (2009). Temperature-dependent EXAFS analysis of embedded Pt nanocrystals. Journal of Physics-Condensed Matter, 21(15), 155302. doi:10.1088/0953-8984/21/15/155302