Title :
Magnetic properties of acicular ultrafine iron particles
Author :
Varanda, Laudemir C. ; Goya, Gerardo F. ; Morales, Maria P. ; Marques, Rodrigo F C ; Godoi, Ricardo H M ; Jafelicci, Miguel, Jr. ; Serna, Carlos J.
Author_Institution :
Instituto de Quimica de Araraquara, UNESP, Araraquara, Brazil
fDate :
9/1/2002 12:00:00 AM
Abstract :
Magnetic properties of acicular (∼60 and ∼200 nm) iron particles, obtained by reduction of alumina-coated goethite particles, are reported. X-ray diffraction and Mossbauer spectroscopy showed that the particles consist of an α-Fe core and a thin surface layer of maghemite. Magnetization data indicated an improvement of ∼28% in the saturation magnetization, coercive field, and squareness for particles with ∼60 nm. This magnetic property enhancement of the present particles, whose size is 40% smaller than those commercially available, could result in a similar decrease of the bit-size for higher density of magnetic media.
Keywords :
Mossbauer effect; X-ray diffraction; coercive force; ferromagnetic materials; iron; magnetic particles; magnetic recording; magnetisation; particle size; α-Fe core; 200 nm; 60 nm; Al2O3-coated goethite particles; Fe; Mossbauer spectroscopy; X-ray diffraction; acicular ultrafine Fe particles; bit-size; coercive field; maghemite surface layer; magnetic media density; magnetic properties; magnetic property enhancement; particle squareness; reduction; saturation magnetization; Furnaces; Hydrogen; Iron; Magnetic properties; Magnetic recording; Oxidation; Saturation magnetization; Spectroscopy; Transmission electron microscopy; X-ray diffraction;
Journal_Title :
Magnetics, IEEE Transactions on
DOI :
10.1109/TMAG.2002.802816
