The Nonlinear Optical, Magnetic, and Mössbauer Spectral Properties of Some Iron(III) Doped Silica Xerogels

Abstract

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, n 2, 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.

Department(s)

Chemistry

Sponsor(s)

Action de Recherche Concertée of the Communauté Française de Belgique
National Science Foundation of Belgium
Ministere de la Region Wallonne

Keywords and Phrases

Doping (Additives); Evaporation; Iron Compounds; Magnetic Properties; Nonlinear Optics; Optical Kerr Effect; Optical Properties; Acetylacetonate Complex; Evaporative Drying; Optical Phenomenon; Silica Gel

International Standard Serial Number (ISSN)

0022-2461

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2006 Springer Verlag, All rights reserved.

Publication Date

01 May 2006

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