Physical, electrical and magnetic properties of nano-sized Co-Cr substituted magnesium ferrites

Co-Cr substituted magnesium ferrite nanomaterials (Mg1-xCoxCrxFe2-xO4 with x 0.0-0.5) have been prepared by the polyethylene glycol assisted micro emulsion method. X-ray diffraction analysis confirms the single-phase cubic close-packed lattice formation of synthesized materials. Hysteresis loops are measured up to field of 4 MA/m and high field region of these loops are modeled using the Law of Approach to saturation to calculate the magnetocrystalline anisotropy constant. The saturation magnetization of the samples increases initially from 148 kA/m for x = 0.0 to 299 kA/m (x = 0.3) and then decreases to 187 kA/m (x = 0.5). Curie temperature for this series is found to be in the range of 618-766 K. Room temperature resistivity increases gradually from 7.5 x 10(8) Omega cm (x = 0.0) to 3.47 x 10(9) Omega cm (x = 0.5). Additionally, dielectric measurements are carried out at room temperature in a frequency range of 100 Hz to 3 MHz. With improvement in the values of the above-mentioned properties, the synthesized materials could be suitable for potential application in some magnetic and microwave devices. (C) 2012 American Institute of Physics. [doi:10.1063/1.3676438]