M Dubiel et al 2009 J. Phys.: Conf. Ser. 190 012123 doi:10.1088/1742-6596/190/1/012123
M Dubiel1, J Haug1, H Kruth1, H Hofmeister2 and W Seifert1
Show affiliationsAg nanoparticles of 1.5 to 7 nm size were produced by ion exchange of soda-lime glass for various duration. Information on local order and thermal vibrations were available by means of X-ray absorption spectroscopy using experiments at the Ag K-edge (25.514 keV). Ratio method and EXAFS fitting procedure were successfully applied to reveal the temperature dependence using the cumulant-expansion method up to third order ones. The temperature dependence of the nearest neighbor Ag-Ag distance appears different from that of polycrystalline Ag foil below 400 K. This effect can be explained by a thermoelastic model describing the mismatch of thermal expansion coefficients of Ag particles and the glass matrix. In addition, the parameter of Ag-Ag bond length of 1.5 nm particles is governed by precursor formation for crystalline Ag nanoparticles. The data of the second cumulant, the Debye-Waller factor (DWF), represent a higher static disorder, especially for nanoparticles of 1.5 – 3.5 nm size, caused by the increasing portion of surface or interface atoms. From the temperature dependent part of DWF we estimated a slightly increased Einstein temperature.
61.05.cj X-ray absorption spectroscopy: EXAFS, NEXAFS, XANES, etc.
62.25.-g Mechanical properties of nanoscale systems
65.80.+n Thermal properties of small particles, nanocrystals, nanotubes
81.40.Jj Elasticity and anelasticity, stress-strain relations
Condensed matter: electrical, magnetic and optical
Issue 1 (2009)
M Dubiel et al 2009 J. Phys.: Conf. Ser. 190 012123
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