Magnetic properties of CoFe2O4 ferrite doped with rare earth ion

A series of CoFe2-xNdxO4 ferrite nanocrystals have been synthesized by the emulsion method. Powder X-ray diffraction (XRD), thermal gravity analysis (TGA) and differential thermal analysis (DTA), TEM, Mossbauer spectroscopy and vibrating sample magnetometer (VSM) were employed to characterize the crystallite sizes, structure and magnetic properties of these ferrite nanocrystals. The effect of substitution Fe3+ ions by Nd3+ ions on structure, magnetic properties of cobalt ferrite nanocrystals was investigated. The value of saturation magnetization for Nd3+-doped samples is less than that of pure cobalt ferrite. The value of coercivity is increased with the Nd3+-doped content. The pure cobalt ferrite powders with crystallite sizes of 10.3 nm achieved values of Ms=53.4 emu/g and Hc=172.0 Oe. However, nanocrystalline CoFe1.8Nd0.2O4 powders with crystallite sizes of 10.0 nm achieved desirable values of Ms=28.0 emu/g and Hc=488.6 Oe. (C) 2005 Elsevier B.V. All rights reserved.