Suitability of Sr 0.5Ba 0.5− xCe xFe 12− yNi yO 19 co-precipitated nanomaterials for inductor applications

Abstract

The present investigation deals with the synthesis and characterization of Ce–Ni ions substituted nanocrystalline strontium–barium hexaferrites (Sr 0.5Ba 0.5Fe 12O 19) by the chemical co-precipitation method, with focus on the optimization of annealing temperature for the hexagonal phase development. The synthesis involves co-precipitation of aqueous solutions of water-soluble salts of strontium, barium and iron, at pH 9 using an ammonium hydroxide solution as a precipitating agent. The optimum temperature of annealing, necessary for the hexagonal phase development, is determined on the basis of thermo-gravimetric analysis (TGA). The co-precipitate is annealed at a temperature of 1323 K for 6 h, to produce a single magnetoplumbite phase of Sr–Ba hexaferrites, with the corresponding average crystallite size ranging from 36 to 48 nm. Observed changes in the lattice structure determined by the powder X-ray diffraction (XRD) studies are not in contradiction with the results of TGA. DC-electrical resistivity increases from 1.8 × 10 10 to 12.5 × 10 10 Ω cm, whereas the drift mobility, dielectric constant and dielectric loss tangent decrease with increasing the Ce–Ni content of the samples. Material of above-mentioned characteristics is considered to be suitable for applications in the microwave and surface mount devices (SMD) for fabricating the multilayer chip inductors (MLCI).