OICC Press Journal of Nanostructure in Chemistry 2193-8865 3 1 (December 2013) 2013 08 02 Magnetic properties of Cr-substituted Co-ferrite nanoparticles synthesized by citrate-gel autocombustion method 10.1186/2193-8865-3-63 EN M Raghasudha Department of Chemistry, Jayaprakash Narayan College of Engineering, Mahabubnagar, Andhra Pradesh, 509001, IN D Ravinder Department of Physics, Nizam College, Basheerbagh Osmania University, Hyderabad, 500001, IN P Veerasomaiah Department of Chemistry, Osmania University, Hyderabad, Andhra Pradesh, 500007, IN Journal Article 2013 08 02 Abstract A series of Co-Cr nanoferrites having the chemical formula CoCr x Fe 2 − x O 4 ( x = 0.0, 0.1, 0.3, 0.5, 0.7, 0.9, and 1.0) were synthesized by citrate-gel autocombustion method at a very low temperature (180°C). The X-ray diffraction analysis of as-synthesized powders and sintered powders has confirmed the formation of single-phase cubic spinel structure. The average particle size of the synthesized ferrites was 6 to 12 nm. Magnetic susceptibility measurements using Faraday magnetic susceptibility balance showed the paramagnetic nature of the ferrites. Magnetic properties of Co-Cr nanoferrites were measured using a vibrating sample magnetometer at room temperature in the applied field of 15 kOe. The saturation magnetization decreased from 33.84 to 13.83 emu/g with increase in Cr 3+ concentrations, indicating the fact that the lesser magnetic Cr 3+ ions substitute Fe 3+ ions in the octahedral sublattice of the ferrite. With improvement in the magnetic properties, the synthesized nanoferrites become soft magnetic materials. Such materials are useful in transformer and motor cores to minimize the energy dissipation with the alternating fields associated with AC electrical applications. The coercivity of pure CoFe 2 O 4 was larger than that of the Cr-doped cobalt ferrites.