title: Optically transparent magnetic nanocomposites based on encapsulated Fe(3)O(4) nanoparticles in a sol-gel silica network.
abstract: Composite Fe(3)O(4)-SiO(2) materials were prepared by the sol-gel method with tetraethoxysilane and aqueous-based Fe(3)O(4) ferrofluids as precursors. The monoliths obtained were crack free and showed both optical and magnetic properties. The structural properties were determined by infrared spectroscopy, x-ray diffractometry and transmission electron microscopy. Fe(3)O(4) particles of 20 nm size lie within the pores of the matrix without any strong Si-O-Fe bonding. The well established silica network provides effective confinement to these nanoparticles. The composites were transparent in the 600-800 nm regime and the field dependent magnetization curves suggest that the composite exhibits superparamagnetic characteristics.
authors: Department of Physics, Cochin University of Science and Technology, Cochin 682022, India.
authors: Senoy
authors: S
authors: Thomas
authors: D
authors: D
authors: Sakthikumar
authors: P A
authors: PA
authors: Joy
authors: Yasuhiko
authors: Y
authors: Yoshida
authors: M R
authors: MR
authors: Anantharaman