Synthesis, structural, and electromagnetic properties of Mn0.5Zn0.5−xMgxFe2O4 (x=0.0, 0.1) polycrystalline ferrites

Abstract

Polycrystalline Mn–Zn and Mn–Zn–Mg ferrites with compositions Mn0.5Zn0.5Fe2O4 (MZFO) and Mn0.5Zn0.4Mg0.1Fe2O4 (MZMFO) were synthesized by the solid sate reaction method at different sintering temperatures. Samples were characterized by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). XRD patterns showed the single phase of the spinel-type ferrite with hematite as impurity phase. Surface morphology reveals that the grain size increases with sintering temperature. The dielectric properties and ac conductivity were discussed in the light of space charge polarization and the electron hoping between the adjacent sites. The dielectric constant and loss tangent of MZMFO ferrite is lower than MZFO ferrite due to the unavailability of ferrous and ferric ions in the octahedral sites. At 1200 and 1250°C MZFO ferrite exhibits dielectric loss peaks and MZMFO ferrite exhibits at 1200°C. The loss peaks were appeared due to matching of the hopping frequency of electrons and the frequency of the applied field. The initial permeability of MZMFO ferrite at 1200°C and 1250°C is lower than that of MZFO ferrite because Mg2+ ion caused an increase of the magnetocrystalline anisotropy and the saturation magnetization. The increment of magnetocrystalline anisotropy is larger than that of saturation magnetization.