Nano-sized crystalline magnetic particles of Ba3Co1.3Zn0.3Cu0.4Fe24O41 hexaferrite was synthesized by sol-gel citrate precursor method. It was characterized using X-ray powder diffraction, thermogravimetric analysis, differential thermal analysis, X-ray fluorescence and atomic force microscopy. The magnetocrystalline anisotropy was calculated from the transverse magnetization isotherms, taking into account the distribution of the easy magnetization axis with the orientation direction of the samples. (c) 2006 Elsevier B.V. All rights reserved.