The Nonlinear Optical, Magnetic, and Mössbauer Spectral Properties of Some Iron(III) Doped Silica Xerogels
Iron(III) species dispersed in silica have been synthesized with a sol-gel process. The iron(III) was introduced as the acetylacetonate complex into a solution of tetraethoxysilane to yield, after evaporative drying, pellets or monoliths. Two gels were dried very slowly over a period of five months in order to prepare a defect free monolith useful for nonlinear optical studies. Z-scan experimental studies on the resulting, transparent, monolithic, doped solid revealed an optical Kerr effect, a third order nonlinear optical phenomenon showing a linear dependence of the refractive index on the irradiance with a nonlinear refractive index, n2, of −1.95 × 10−11 cm2/W. Magnetic susceptibility studies between 4.2 and 295 K revealed paramagnetic behavior with a Curie constant of 4.433 (emu/mol)K and a Weiss temperature of −7.1 K. Magnetization studies at 5 K and at applied fields of up to 4 T and Mössbauer spectral studies between 4.2 and 295 K revealed a 50:50 mixture of paramagnetic species and nanoparticles with an average particle radius of 1.3 ± 0.2 nm. A blocking temperature of 70 K and a magnetic anisotropy energy of 2.4 × 105 J/m3 are derived from the Mössbauer spectra.
V. Rosso and Y. Renotte and Y. Lion and F. Grandjean and J. Pirard and J. Delwiche and G. J. Long and L. Rebbouh and B. Heinrichs and M. J. Hubin-Franskin, "The Nonlinear Optical, Magnetic, and Mössbauer Spectral Properties of Some Iron(III) Doped Silica Xerogels," Journal of Materials Science, Springer Verlag, Jan 2006.
The definitive version is available at http://dx.doi.org/10.1007/s10853-006-6336-3
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