M Niyaifar - Department of Science, College of Physics, Ahvaz Branch, Islamic Azad University, Ahvaz, Iran
A Bahadori - Department of Science, College of Physics, Ahvaz Branch, Islamic Azad University, Ahvaz, Iran
A Hassanpour - Department of Science, College of Physics, Ahvaz Branch, Islamic Azad University, Ahvaz, Iran

NanocrystallineNickel–Zinc–Cobalt ferrites with compositional formula Ni0.7-xZn0.3CoxFe2O4(0⩽x⩽0.4),have been successfully synthesized by sol–gel autocombination method using metal nitrates in citric acid.The structural and magnetic properties of these ferrites have been characterized at room temperature. The X-Raydiffraction (XRD) patterns of the particles confirmed the formation of single-phase cubic spinel structure. The averagecrystallite size lie in the range of 34-39 nm. Infrared absorption spectrashow one significant absorptionbandaround 580 K1_, and the wavelength decreases gradually with increasing Co content.Magnetizationmeasurements of ferrite spinels were carried out at room temperature by a vibrating sample magnetometer (VSM)andhysteresis patterns demonstratedincrease in saturation magnetization and coercive force with increasing Coconcentration.

Ferrites;Sol–gel auto combination method; X-ray diffraction;Infraredspectroscopy; Magnetic properties