Effect of W ion doping on magnetic and dielectric properties of Ni-Zn ferrites by 'one-step synthesis'

摘要

W-doped Ni-Zn ferrites with a nominal composition of Ni_(0.05)Zn_(0.050W_xFe_(2-x)0_4 (where x = 0,0.02,0.04,0.06, and 0.08) were prepared by one-step synthesis through the incorporation of WO3 into the raw powders. The magnetic and dielectric properties of the as-prepared Ni-Zn ferrites were investigated. All samples have a typical spinel cubic structure. With increasing amount of W ions doped, the lattice constant decreases, while the grain size increases. The density and diameter shrinkage of the samples raise with small amount of W ions doped, but drop down with large amount of W ions doped. However, an uneven abnormal growth and closed pores were observed when too much of WO3 was added. The saturation magnetization of the samples increases with small amount of W ions doped, but decreases with large amount of W ions doped, and the coercivity shows an opposite trend. The Curie temperature raises with increasing amount of W ions doped. Both the real and imaginary parts of permeability of the ferrites decrease with increasing amount of W ions doped, while the natural resonance changes very little. Both the dielectric constant and dielectric loss present a decrease with small amount of W ions doped, but increase with large amount of W ions doped.