The effect of calcining temperature on the magnetic properties of the ultra-fine NiCuZn-ferrites

In this study, the ultra-fine NiCuZn-ferrite was prepared by a coprecipitation method. The magnetic properties were investigated in terms of calcining temperature. The ferrite powders, Ni0.206Cu0.206Zn0.618Fe1.94O4-δ, were initially heat treated at various temperatures of 300-750 deg. C, and then sintered at the final temperature of 900 deg. C. The average particle size calculated by a XRD pattern and confirmed by a transmission electron microscope (TEM) micrograph was 7.5 nm. The calcining temperature was an important factor for microstructures and magnetic properties of the sintered ferrite. Scanning electron microscope (SEM) micrographs showed a uniform grain growth with small pores and high densification at the calcining temperature of 450 deg. C. From the results of magnetic property measurements, the ferrite calcined at 450 deg. C showed higher initial permeability (170) and quality factor (72) than those of other calcining temperatures