Structural, dielectric and magnetic properties of Mn+2 doped cobalt ferrite nanoparticles

•The average crystalline size increased with increased Mn-doped ratio.•The magnetic of ferrite was changed after substituting cobalt ferrite with Mn+2.•The saturation magnetization was decreased with increasing Mn-doping ratio.•The prepared nanoparticles showed promising properties for used in gas sensing, inductors, and transformers applications. Manganese (Mn+2) doped spinel cobalt ferrites nanoparticles (NPs) having composition (MnxCo1−xFe2O4 where x = 0.2, 0.4, 0.6 and 0.8) were synthesized by sol-gel precipitation method. The structural, dielectric and magnetic properties were characterized via X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), LCR meter, and vibrating sample magnetometer (VSM). The average crystallite size (D) was found to increase from 10.79 nm to 14.18 nm with increasing the Mn+2 doping ratio from (0.2 to 0.6) then decrease to 9.95 nm with further increasing of Mn+2 to (0.8). FTIR spectrum confirmed the formation of the spinal structure of ferrite, where the main observed bands (416.64–459.07 cm−1) assigned to the octahedral complexes and (513.08–574.81 cm−1) assigned to tetrahedral complexes. The dielectric properties of samples found to be decreased with increasing the doping ratio. While the hysteresis loop obtains from VSM indicated the formation of soft magnetic material and the saturation magnetization decrease from 56 emu g−1 (Mn+2 = 0.2) to 38 emu g−1 (Mn+2 = 0.8).