Hexagonal microstructure, magnetic and dielectric properties of iron deficient BaNi_xZn_xFe_12−2xO₁₉ (x = 0.0−0.5) hexaferrites

Abstract

This work is mainly devoted to study the magnetic properties and dielectric properties BaNi_xZn_xFe_12−2xO₁₉ (x = 0.0, 0.1, 0.2, 0.3, 0.4, 0.5)/ BNZFO. These samples were synthesized by the hydrothermal method followed by calcination at 950 °C. The X-ray diffraction patterns revealed that BNZFO samples were crystallized into a hexagonal structure with the space group P63/mmc. The lattice parameters increase with the increase of Ni²⁺ and Zn²⁺ ions substitution in BNZFO. The crystallite size significantly increased from 1.3 µm to 29 µm with the increase of Ni²⁺ and Zn²⁺ ions composition. FESEM studies revealed that hexagonal plates like morphology with small fraction of rods like grains (except for x = 0.0) with an average grain size from 1.72 to 4.96 µm. The FTIR spectra showed two prominent peaks at 583 and 430 cm⁻¹ indicated the formation of Fe–O bonds in all samples. The room temperature M-H curves showed that the coercive field was decreased from 3091 to 671.92 Oe while the increase in saturation magnetization was noticed from 48.22 to 63.37 emu/g as a function of ‘x’ from 0.1 to 0.4. The narrow optical band gap values of BNZFO were altered between 1.36 to 1.88 eV and discovered the semiconducting nature of samples. The increasing trend of dielectric constant and dielectric loss values was observed with an increase in x = 0.0 to 0.5. The Maxwell–Wagner’s interfacial polarization effect was observed in all samples (x = 0.0–0.5). The complex modulus and impedance spectroscopy analysis indicated non-Debye type relaxations and the electrical conduction mechanism due to both grain and grain boundary contributions among all samples. In view of all these properties, BNZFO samples are potential candidates for opto-electronic, magneto-optic, magnetic-recording devices, photocatalytic and sensor-based applications.