Effect of Aluminum Substitution on Structural and Electromagnetic Properties of Nanocrystalline MgCuMn Ferrites

摘要

The effect of substitution of nonmagnetic Al~(3+) ions on the structural and electromagnetic properties were studied in nanocrystalline ferrite series of Mg_(0.8)Cu_(0.2)Al_xFe_(1.95-x)Mn_(0.05)O_4 where x varies 0-0.4 in steps of 0.1. This series was synthesized by using microwave hydrothermal method. The nanocrystalline ferrite phase was observed at temperature 150°C/40 min. Synthesized powders were characterized using X-ray diffraction (XRD) and transmission electron microscopy (TEM). The synthesized powders were densified using microwave sintering method at 950°C/40 min. The sintered samples were characterized using XRD. Surface morphology was observed by using field effective scanning electron microscopy (FESEM). The electrical and magnetic properties were measured at room temperature. These results led us to interfere that the values of d.c resistivity increases and dielectric constant, initial permeability, saturation magnetization and Curie temperature were observed to be decreased with the substitution of Al~(3+) ions with those of Fe~(3+). The low dielectric and magnetic losses and low magnetization exhibited by aluminum substituted MgCuMn ferrites makes them find applications in microwave devices.