Magnetic Hysteresis and Complex Initial Permeability of Cr³⁺ Substituted Mn-Zn Ferrites

Abstract

The impact of Cr 3+ ion on the magnetic properties of Mn 0.50 Zn 0.50 Cr x Fe 2- x O 4 (with x = 0.0, 0.1, 0.2, 0.3, 0.4 and 0.5) has been studied. Ferrite samples were synthesized by combustion method and sintered at various temperatures (1250 ° C, 1300 ° C and 1350 ° C). The structural properties were investigated by means of X-ray diffraction patterns and indicated that the samples possess single phase cubic spinel structure. The lattice parameter decreases with the increase in Cr 3+ content, as the ionic radius of Cr 3+ ion is smaller than that of Fe 3+ . The average grain size (D) , bulk density ( ρ B ) and initial permeability （ μ i ’ ） decreases with increase in Cr 3+ content whereas porosity follows its opposite trend. The ρ B was found to increase with increase in Cr 3+ content as the sintering temperature ( T s ) is increased from 1250 ° C to 1350 ° C . The T s affects the densification, grain growth and （ μ i ’ ） of the samples. The （ μ i ’ ） strongly depends on average grain size, density and intragranular porosity. The B-H loops of the compositions were measured at room temperature. The saturation magnetization ( M s ), coercivity ( H c ) and hysteresis losses were studied as a function of Cr 3+ content. The M s was found to decrease with the increase of Cr 3+ content, which is attributed to the dilution of A-B interaction.