Effect of synthesis on structural and magnetic properties of cobalt doped Mn–Zn nano ferrites

• Co-precipitation and hydrothermal synthesis of Co2+ doped Mn–Zn ferrites.
• Structural parameters have effect due to synthesis route.
• Enhanced magnetic properties for samples prepared from hydrothermal technique.
• Synthesis method has great influence on the structural and magnetic properties of Mn–Zn nano ferrites.

A series of Co2+ doped Mn–Zn ferrite ceramics with the formula Mn0.5Zn0.5−xCoxFe2O4 (x = 0, 0.25 and 0.50) have been successfully synthesized using polyethylene glycol-assisted co-precipitation and hydrothermal methods. The structural characterization of the samples has been done using room temperature X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). XRD patterns revealed the formation of pure FCC spinel phase without any impurity peaks. SEM showed the uniform, homogenously spherical nanoparticles prepared from controlled reaction of hydrothermal method. Lattice constant found to be smaller for samples prepared from hydrothermal treatment. The average crystallite size of all nanoparticles were estimated using Scherrer’s formula and found to lie between 10–25 ± 3 nm with small size distribution of particles prepared by hydrothermal method. Bond length (A–O) and ionic radii (rA) at A-sites are smaller than the bond length (B–O) and ionic radii (rB) at B-sites for sample series prepared by two methods. Magnetic properties were studied using Physical Property Measurement System (PPMS), Quantum Design Vibrating Sample Magnetometer (VSM) option. Magnetic properties including saturation magnetization was higher (65 emu/g for x = 0.25) for hydrothermal treated samples. The method of preparation influenced the size of particle which in turn has strong affect on magnetic properties of prepared samples. The enhanced magnetic and structural properties of these nano ferrites made them a potential candidate to use in electromagnetic devices.