The role of Mg substitution on the microstructure and magnetic properties of Ba Co Zn W-type hexagonal ferrites

Abstract A series of W-type hexagonal ferrites with the composition BaCoZn 1− x Mg x Fe 16 O 27 (0⩽ x ⩽0.6) were prepared by the conventional ceramic method to study their structural and magnetic properties as a function of temperature and composition. The characterization using X-ray diffraction indicated that a hexagonal W-type single-phase structure and the effect of composition on the unit cell parameters, density and porosity was studied. The variation of the magnetic susceptibility ( χ M ) with temperature for all the investigated samples in the temperature range (300–800 K) shows three regions of behavior that was explained on the basis of the distribution of Zn 2+ and Mg 2+ ions in the lattice and leads to the anomalous behavior of the effective magnetic moment μ eff . The Curie temperature indicated that the critical concentration is at x =0.5. Paramagnetic nature of the samples above the Curie temperature is observed. The Curie Weiss constant θ calculated from the plot of 1/ χ M vs. T (K) is in agreement with the expected value. The effective magnetic moment μ eff decreases with increasing the intensity of magnetic field. The possible mechanisms contributing to these properties are discussed in the text.