Investigation of Structural and Magnetic Properties on Mg1-xZnxFe2-xAlxO4 (0.0 <= x <= 0.8) Nanoparticles

Abstract

A mixed spinel ferrite nanoparticle, Mg1−xZnxFe2−xAlxO4 NPs (0.0 ≤ x ≤ 0.8), were synthesized effectively by co-precipitation method and sintered at 600 °C for 10 h. The structural and magnetic properties of the products were studied through X-ray powder diffraction (XRD), scanning electron microscopy, transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM) and vibrating sample magnetometer. The cubic spinel phase was confirmed by XRDs with particle size between 24.5 and 40.2 nm. The lattice parameters for the products are increased with increasing the Zn2+ and Al3+ ratio due to the successfully integrated into the cubic system without changing the original structure. Although it was observed from the cation distributions, that the cubic phase is was an inverse spinel, wherein which the Fe3+ and Mg2+ ions occupied both the tetrahedral A and octahedral B- sites, the Zn2+ ions preferred to occupy the A- sites and Al3+ occupy preferred the B -sites. The morphology of the nanoparticles NPs detailed was using TEM, HR-TEM, and SAED in selected area confirmed the particle size and crystalline spinel structure. Magnetization results at room temperature presents a narrow hysteresis loop for all ratios, which is specific of the soft magnetic materials. Also, we noticed that the increase in the magnetization with increasing the ratio of Zn2+ and Al3+ consistent with the enhancement of crystallinity. Moreover, we found that the saturation magnetization, coercively and remanent for Mg1−xZnxFe2−xAlxO4 where x = 0.6 sample is the highest, indicating the potential of Zn and Al substitution in enhancing the magnetic properties of magnesium ferrite. According to AC magnetic susceptibility measurements, the nanoparticles exhibit superparamagnetic/spin glassy behaviour with a very strong inter-nanoparticles interaction. Additionally, AC susceptibility measurements indicated a relative sensitivity of samples to the variation of applied frequency, which is an important result for the applications in hyperthermia based therapy. This is the first study in which both Zn2+ and Al3+ ions with varying concentration were tried to substitute into MgFe2O4 simultaneously and their effects on magnetic properties of MgFe2O4 was investigated.