Modified sol–gel synthesis of nanosized magnesium titanium substituted barium hexaferrite and investigation of the effect of high substitution levels on the magnetic properties

Abstract

Nanosized BaFe12−xMg0.5xTi0.5xO19 (X=0.0–5.0) is synthesized by a modified sol–gel process that provides a reliable capability for efficient substitution of elements such as Ti in high substitution levels such as X=5. Efficient substitution of Ti in a hexaferrite by sol–gel method is not easy due to some technical challenges unless by using a high calcination temperature which negates the formation of nanosized particles. The effectiveness of substitution is improved by using several modifications in conventional sol–gel process. Application of citrato–peroxo–titanate as a titanium source instead of commercial sources can be mentioned as one of the most significant modifications. Moreover, a certain oxidizing condition in all samples with different substitution levels is kept by setting oxidizing factor as a processing parameter. Because of the modifications, achievement of Mg–Ti substituted Ba-hexaferrite nanoparticles with a mean particle size of 30nm becomes possible at a calcination temperature of 950°C. Variations of crystalline structure and magnetic properties of Ba-hexaferrite nanoparticles with substitution amount are also investigated and discussed in detail.