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

W-doped Ni–Zn ferrites with a nominal composition of Ni0.5Zn0.5WxFe2−xO4 (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.

► One-step direct synthesis of Ni–Zn ferrites.
► Doping of W ion into Ni–Zn ferrites.
► Magnetic and dielectric properties of doped Ni–Zn ferrites.