Synthesis and magnetic properties of CoAlFe2O4 nanoparticles

Nanosized particles of CoAlxFe2-xO4, where 0 <= x <= 2, were synthesized by the sol-gel combustion method and the magnetic properties of these compounds were investigated. According to X-ray diffractograms, the samples are single phase and the crystallite size is between 7 and 25 nm. The room temperature saturation magnetization of the samples was estimated from the cation distribution and ferromagnetic resonance spectra were used to determine the magnetocrystalline anisotropy. The results show that the saturation magnetization and the magnetocrystalline anisotropy vary over a wide range, from maxima of M-s = 0.42 MA/m and K = 0.39 kJ/m(3) for x = 1.0 to minima of almost zero for x approximate to 1.4, a result that could be useful for practical applications of these materials.