Preparation and magnetic properties of Ba–Co2Z and Sr–Zn2Y ferrites

We have prepared Ba–Co2Z and Sr–Zn2Y ferrites by mixing SrCO3 (BaCO3), Co2O3 (ZnO), and Fe2O3 and calcinating in air and O2. The effects of sintering atmosphere (O2 and Ar) and sintering temperatures (1373–1573 K) on the structural, magnetic, and electrical properties have been measured. The Ba–Co2Z sample sintered at 1573 K under a flowing O2 exhibits superior dc electrical resistivity (∼108 Ω-cm), high initial permeability (u′∼21), and low loss factor (F∼1.6×10−3) at 20 MHz. The related XRD and SEM/EDS analyses of these samples have also been studied to correlate these properties. These results indicate that significant modification of magnetic properties up to 20 MHz can be achieved with the addition of the quaternary component and proper control of the processing oxygen atmosphere.