Structural, morphological, dielectric and magnetic properties of La3+ion doped Zn–Mg based spinel ferrites nanomaterials for technological applications

In the current study, structural, morphological, dielectric and magnetic investigations of rare earth ion (La3+) doped Zinc-Magnesium based spinel ferrites is investigated. The series of La3+ mixed Zn-Mg based nanoparticles having same quantity with chemical combination Zn_0.5Mg_0.5La_xFe_2-xO₄ (0.00 ≤ x ≤ 0.10 with difference of 0.02) were synthesized by the sol-gel technique followed by annealing at 800 °C for 3 h. X-ray diffraction (XRD) results confirmed the crystalline single-phase and spinel-cubic formation of the synthesized series. The crystallite size was calculated using the Scherrer formula and Size-Strain plot. Transmission electron microscopy (TEM) was used to explore the morphology and size of La3+ ion doped Zn-Mg ferrites. The presence of two vibrational frequency modes was confirmed by the FTIR spectrum. The dielectric properties including dielectric constant, tangent loss, electric modulus and Ac conductivity were measured using an impedance analyzer over a frequency range of 25 Hz to 2 MHz, and the results were interpreted through the Maxwell-Wigner method. Interestingly, the La3+ substitution has changed the behavior of the dielectric constant (ԑʹ) and dielectric loss (ԑʺ). Cole-Cole plots were examined to study the behavior of the grain and their grain boundaries. The magnetic behavior of La3+ mixed spinel ferrites were elaborated by magnetic field varying from −20 to +20 kOe. The magnetic characteristics showed that the series possess soft ferromagnetic nature. This shows the potential of La3+ to enhance the performance of nanomaterials for their application in energy systems such as batteries, supercapacitor and magnetic storage devices.