Specific magnetic structure forming in polymer nanocomposites containing magnetite nanoparticles

¹Institute of Physics of the Earth, Russian Academy of Science, Moscow, Russia
²Lomonosov State University, Department of Physics, Moscow, Russia
³Semenov Institite of Chemical Physics, Russian Academy of Science, Moscow, Russia

Abstract

[1]  The specific distribution of Fe₃O₄ nanoparticles synthesized in situ in a polymeric PVA matrix was studied using the methods of magnetic measurements, transmission and depth-selective Mössbauer spectroscopy, and tunnel microscopy. The magnetic nanoparticles volumetric concentration C_v varied in the study samples from 0.6 vol. % to 43 vol. %. The size of the nanoparticles, measured using the X-ray diffraction, was found to be 10-20 nm. In the case of low C_v values the nanoparticles showed the composition of maghemite. At growing C_v concentrations, the product of the synthesis was partially oxidized magnetite. The contribution of the particles participating in the magnetic interaction at room temperature was estimated from the hyperfine magnetic splitting of the Mössbauer spectra. The blocking temperatures of the films of all compositions were found to be in the region of 300^o C. This study revealed the high planar and linear magnetic anisotropy of the remanent saturation magnetization and of the remanent laboratory synthesis magnetization (LSM). The Mössbauer and microscopic studies revealed that during the synthesis the particles are distributed in the nanocomposite irregularly over the matrix, remaining almost isolated at the surface of the films and producing, in the lower part of the film, the chains of interacting nanoparticles, extending parallel to the film plain along the resulting trend. This chain structure is treated here as an artificial analog of fossil bacterial structures and biofilms, contributing to the magnetization of sedimentary rocks.

Received 15 December 2004; revised 10 February 2005; accepted 1 March 2005; published 14 August 2005.

Keywords: magnetic nanoparticles, thin films, magnetic properties, magnetic anisotropy.

Index Terms: 1500 Geomagnetism and Paleomagnetism; 1594 Geomagnetism and Paleomagnetism: Instruments and techniques; 1518 Geomagnetism and Paleomagnetism: Magnetic fabrics and anisotropy.

Citation: Gendler, T. S., A. A. Novakova, and E. V. Smirnov (2005), Specific magnetic structure forming in polymer nanocomposites containing magnetite nanoparticles, Russ. J. Earth Sci., 7, ES4003, doi:10.2205/2005ES000177.