Physical Interpretation of the morphology in the relaxation mechanism of Ba Hexagonal Nano-Ferrites (BaCoxCdxFe12-2xO19): Impedance Modelling, AC conductivity, dielectric modulus, and electrical modulus parameters

Abstract

Abstract This study describes in detail the sol-gel synthesis of doped M-type Ba hexagonal ferrite with Co2+ and Cd2+. In order to explore the crystal structure and grain morphology, X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) have been used. At room temperature, the dielectric, impedance, electric modulus, and conductivity characteristics were investigated using an impedance analyzer, as well as the physical interpretation of morphology in the relaxation mechanism. The structural parameters indicated the formation of hexagonal M-type crystal structures. Doping with large quantities of Co2+ or Cd2+ caused the unit cell to become smaller, which in turn reduced the lattice constants to lower values. The examination of grain morphology revealed that the doping led to the formation of needle-like grains. The change of AC conductivity from 0.00022 to 1.04*10− 7 Ωm− 1 with frequencies ranging from 1 KHz to 2 MHz demonstrated that the electron hopping process was the primary cause of the high electrical conductivity in these ferrites. As a function of doping, the dielectric spectrum analysis showed that there was a decrease in the dielectric constant and an increase in the loss tangent. Within the frequency range of 1 KHz to 2 MHz, the fluctuation of the dielectric constant (ε′) from 135.94 to 3.59 and the loss tangent (tan σ) from 3.67 to 0.11 was observed. The relaxation of conductivity was seen for different levels of composition, which correlated with the non-Debye type of behaviour proven by the electric modulus spectra. Both relaxation time and AC conductivity decreased with doping. The conductivity relaxation and dielectric relaxation contributed to the charge transport mechanism in the BaCoxCdxFe12−2xO19. Electrochemical impedance spectroscopy software resulted in impedance curves that corresponded with empirically measured impedance values. There was consistency between the calculated grain and grain boundary characteristics as well as the distribution of grains /grain boundaries observed in the micrographs.