Effect of Copper Substitution on the Structural, Magnetic, and Dielectric Properties of M-Type Lead Hexaferrite

Abstract

In the present study, Cu-substituted M-type lead hexaferrites with chemical composition PbCuxFe12−xO19 (x = 0.0, 0.2, 0.4, 0.6, 0.8, and 1.0) have been synthesized using a co-precipitation method. As-obtained precursors were preheated at 550°C for 4 h in a muffle furnace, followed by final heating at 1150°C for 5 h. All heated samples were characterized using various instrumental techniques like Fourier transform infrared (FTIR), x-ray diffraction (XRD), Mossbauer spectroscopy, vibrating sample magnetometer (VSM), and low-frequency dielectric measurements to investigate the effect of copper substitution on the structural, magnetic, and dielectric properties. FTIR spectra of all heated samples showed two absorption bands confirming the formation of ferrite. XRD analysis of all samples confirmed the formation of a majority of M-type hexaferrite phase with secondary phases. The coercivity (HC), saturation magnetization (MS), and remanence magnetization (Mr) are found to decrease with copper content (except the x = 1.0 composition). The coercivity is found to change from 8 kA m−1 to 27 kA m−1, and this depicts the magnetically soft nature and multi-domain structure of the prepared ferrites. Mossbauer spectra indicate that the 12k site is more affected by Cu substitution. This means that Cu prefers to occupy the 12k site, which increases the ferrimagnetic order and reduces the saturation magnetization. The dielectric study of all heated samples showed the frequency-dependent phenomenon. Each composition showed a single semicircular arc due to contributions of grain and grain boundaries resistance in Cole–Cole plots.