Effects of SnO 2 addition on the microstructure and magnetic properties of NiZn ferrites

Abstract

The microstructure and magnetic properties of SnO 2-doped NiZn ferrites prepared by a solid-state reaction method have been investigated. Due to its low melting point (∼1127 °C), moderate SnO 2 enhanced mass transfer and sintering by forming liquid phase, which accelerated the grain growth. However, excessive SnO 2 producing much of liquid phase retarded mass transfer and sintering, leading to a decrease in grain size. The diffraction intensity of the samples doped with SnO 2 addition was stronger than that of the sample without addition. The lattice constant initially decreased up to a content of 0.10 wt% and showed an increase at higher content up to 0.50 wt%. The initial permeability ( μ i) initially increased up to a content of 0.15 wt% and showed a decrease at higher content up to 0.50 wt%; however, losses ( P L) measured at 50 kHz and 150 mT changed contrarily. Both saturation induction ( B S) and Curie temperature ( T C) decreased gradually with increasing SnO 2. Finally, the sample doped with 0.10–0.15 wt% SnO 2 showed the higher permeability and lower losses.