Effects of impurity Na + ions on the structural and magnetic properties of Ni–Zn–Cu ferrite powders: An improvement for chemical coprecipitation method

Abstract

Ni–Zn–Cu ferrite powders with nominal composition Ni 0.4− x Zn 0.6Cu x Fe 2O 4 ( x=0.00–0.20) were prepared via chemical coprecipitation method. X-ray diffractometer, vibrating sample magnetometer, scanning electron microscopy, inductively coupled plasma-atomic emission spectrometry and energy dispersive spectrum were used to study the effects of impurity Na + ions on the structural and magnetic properties. As a result, it was found that the impurity Na + ions affect the crystalline structures and magnetic properties greatly. Moreover, the heterogeneous distribution of impurity Na + ions and the formation of Na compounds retard the phase formation and the grain growth of specimens. Our study also reveals that for the chemical coprecipitation method, a second washing process introduced after drying can eliminate the impurity Na + ions effectually and thus helps in the formation of single-phase structure and the growth of grains, which is very important for the improvement of magnetic properties and the preparation of ferrites via chemical coprecipitation method.