Effect of Nd³⁺ doping on magnetic and dielectric properties of SrFe₁₂O₁₉ hexaferrite synthesized by coprecipitation method

Magnetic and dielectric properties of hexagonal ferrites important for applications in microwave absorbers are strongly determined by the processing conditions. We studied dielectric and magnetic response of Sr_{1-x}Nd_{x}Fe₁₂O₁₉ (x=0, 0.03, 0.05, 0.07, 0.09) solid solutions obtained by coprecipitation method. The structure of the samples was controlled by X-ray diffraction and scanning electron microscope images revealed that the powder is a mixture of small nanograins and crystallites of 500 nm-1 μm in size. Nd³⁺ doping was found to result in an increase in the coercive field which we would like to relate to the domain wall pinning. The doping-induced changes are monotonous with x up to 0.07. The observed dispersion of permittivity was found to be correlated with the frequency behaviour of electric conductivity of the samples.