Study the effect of Bi2O3 and sintering temperature on the electromagnetic properties of SrFe8Al4O19 ceramic for permanent magnet applications

Abstract

A composition of SrFe8Al4O19 ceramic is prepared by the conventional solid-state route. The effect of Bi2O3 and different sintering temperatures (Tsin) on the magnetic, electrical and dielectric properties have explicitly been studied. Their consequences in the electromagnetic properties are extensively tried to explore for better magnetic behavior in permanent magnet applications. A large coercivity (Hc) value (>5 kOe) is found for all the sintered samples, showing good hard magnetic characteristics. The highest Hc ∼ 13.05 kOe is found for the 3 wt% Bi2O3 samples, sintered at 1150 °C. Large Hc is very useful in better torque generation for the rotational application of permanent magnets. The sample sintered at 1050 °C with 3 wt% Bi2O3 is optimized to obtain a higher energy density of ∼5.5 MGOe for SrFe8Al4O19 ceramic. The variation trend of frequency-dependent ac-resistivity and ac-conductivity is described based on the Maxwell-Wagner and Koop model for understanding the conduction mechanism of charge carriers. The high resistivity of the samples ensures low eddy current losses in the system and favors their utilization in permanent magnets to improve the performance. © 2022 Elsevier B.V.