Influence of preparation method on structural, optical and magnetic properties of synthesized Zn0.5Mg0.5−xNixFe2O4 nano-ferrite

Structural, optical, and magnetic properties of ferrite series with chemical formula Zn _0.5 Ni _x Mg _0.5−x Fe _2 O _4 (x = 0.0, 0.1, 0.2, 0.3 and 0.4) were investigated. Co-precipitation and sol–gel methods were used to synthesis the samples and to investigate further the influence of these preparation methods on the properties of Zn _0.5 Ni _x Mg _0.5−x Fe _2 O _4 nano-ferrites. X-ray diffraction and Fourier-transform infrared spectroscopy revealed that the samples crystallize in a cubic spinel structure with space group Fd3m:1. The crystallite size of Zn _0.5 Ni _x Mg _0.5−x Fe _2 O _4 nanoparticles was decreased from 19.15 to 11.65 nm with increasing Ni content for the samples of co-precipitation method, while the opposite behavior was observed in case of sol–gel method which was increased from 13.90 to 21.90 nm. Moreover, the optical investigation by UV-visible spectroscopy revealed that the energy band gap of the samples of co-precipitation method ranged (6.04–6.08) eV compared to (4.44–4.50) eV of sol–gel method. For both methods, substitution of Ni ^+2 by Mg ^+2 in Zn _0.5 Ni _x Mg _0.5−x Fe _2 O _4 affects the remanent magnetization (M _r ), coercivity (H _c ) and saturation magnetization (M _s ) suggesting the super-paramagnetic behavior of the samples. The substitution of Ni resulted in small values of coercivity ranged 0.758 to 164.62 Oe. The M _s was ranged 20.39 to 127.57 emu g ^−1 and an enhancement in magnetization was observed which increases the value of M _s that was found to be maximum with x = 0.4 of co-precipitation method (127.57 emu g ^−1 ). The magnetic behavior of synthesized Ni doped nanoparticles makes them suitable candidate for sensing and high-frequency applications and for use in hyperthermia treatment. The characterization outcomes may recommend that co-precipitation method is preferred over sol–gel method for refined structure and preferable properties of Zn _0.5 Ni _x Mg _0.5−x Fe _2 O _4 nanoparticles.