Design of dielectric and photocatalytic properties of Dy–Ni substituted Ca0.5 Pb0.5−xFe12−yO19 M-type hexaferrites

The structure, dielectric response, and photocatalytic properties of Dy–Ni substituted calcium–lead hexaferrite with chemical formula Ca0.5 Pb0.5−x Fe12−yO19 (x = 0.00–0.1, y = 0.00–1.00) prepared by sol–gel auto-combustion method were investigated. The characterization techniques, such as XRD, EDX, and scanning electron microscopy, confirmed the single hexagonal phase. SEM analysis affirmed the presence of fine grained particles with well-defined shape and size. The effect of Dy–Ni substitutions on the dielectric response was analyzed using polarization versus electric field loop instrument. The doped materials have demonstrated the smaller resistivity (1820–250 Ω⋅m) and dielectric constant (5.1 × 106–1.09 × 106) which could be used in optical devices. The doped materials have also been explored for the catalytic degradation of Methylene blue (MB) dye in the presence of visible light. The band gap of the precursor and Ca0.5 Pb0.5−x Dyx Niy Fe12−yO19 (x = 0.1 and y = 1.00) calculated by Tauc plots have been observed as 2.75 eV and 2.17 eV, respectively. A dye degradation efficiency of 85.40% at 668 nm has been recorded for 10 mg/L of dye solution within 105 min. The doped hexaferrite materials may prove a remarkable contender in the domain of high-frequency devices as well as environmental remediation.