Magnetic and electromagnetic wave absorption properties of α-Fe/Z-type Ba-ferrite nanocomposites

The saturation magnetization values (M-s) of alpha-Fe/Ba3Co1.8Fe23.6Cr0.6O41 nanocomposites prepared by mechanically alloying alpha-Fe with Ba3Co1.8Fe23.6Cr0.6O41 powders increased with increasing the concentration of alpha-Fe. alpha-Fe/Ba3Co1.8Fe23.6Cr0.6O41 nanocomposites showed higher coercivity values than alpha-Fe and Ba3Co1.8Fe23.6Cr0.6O41 because of the effects of shape anisotropy and exchange bias. The resin compacts with 33.5 vol % alpha-Fe/Ba3Co1.8Fe23.6Cr0.6O41 (38, 70, 85 vol % alpha-Fe) powders provided good electromagnetic wave absorption performances in ranges of 7.5-16.0, 5.4-10.5, and 4.3-8.3 GHz over the absorber thicknesses of 1.3-2.5, 1.6-3.0, and 1.7-3.2 mm, respectively. (c) 2006 American Institute of Physics.