Influence of Bi3+ ions substitution on calcium-lead hexaferrite's structural, magnetic, and dielectric properties

The current study investigated the effect of bismuth ion dopants on the morphological, magnetic, and dielectric properties of calcium-lead hexaferrite (Ca1 - xPbxFe12 - yBiyO19, x = 0.5, y = 0.2 to 0.8)-nano-sized particles are synthesized by a sol-gel auto-combustion technique assisted by microwave. The crystalline phase of synthesized materials is checked by XRD data plots up to x = 0.8, indicating that the materials are single-phase hexagonal ferrites with an average crystalline size of 33-50 nm produced with a space group P63/mmc. Calcium hexaferrite gains coercive force by adding Pb2+ and Bi3+ ions from 1240.7 to 2949.5 Oe; however, the saturation magnetization increases 41.997 emu/g for x = 0.4 and it begins to fall when the Bi3+ density rises. Squareness ratios for all specimens were reported to be more undersized than the ideal value of 0.5, confirming that the synthesized Bi-substituted Ca-Pb hexaferrite is formed of nanoparticles with a single magnetic domain. The conductivity, relative permittivity, and tangent loss properties of each specimen were measured using temperature- and frequency-dependent electrical and dielectric tests. The power law rules were validated by ac conductivity tests, primarily reliant on Pb-Bi concentration. The grains-grain borders were the primary cause of conduction in all specimens. The dielectric constant of Ca-Pb hexaferrite results in a normal dielectric distribution, and the frequency highly dependent on the dopant amount. The charge transport mechanism in hexaferrite can be connected to the observed shift in tangent loss with wavelength. It can be used for various purposes, including electromagnets and magnetic memory media.