Fabrication, structural, dielectric and magnetic properties of tantalum and potassium doped M-type strontium calcium hexaferrites

Tantalum-potassium substituted strontium calcium hexagonal ferrites with chemical composition Sr0.5Ca0.5Fe12-2xTaxKxO19 (x = 0.0, 0.1, 0.2, 0.3, 0.4) have been synthesized by the sol gel combustion procedure. The structural and morphological characterizations of the synthesized hexaferrites were performed by X-ray diffraction and scanning electron microscopy, respectively. Dielectric and magnetic properties of these samples were also inspected. XRD analysis revealed that all the prepared compounds have pure magnetoplumbite phase and their mean crystallite size was between 34 and 44 nm. The dielectric parameters present resonance type behavior at higher frequency (GHz) region. The dielectric constant increases as the dopant contents increase. The saturation magnetization and remanence show decreasing trend as the concentration of dopants rise in the range of applied magnetic field. The coericivity of all the prepared samples rises with Ta-K concentration and is high enough to be used for longitudinal magnetic recording media. (C) 2015 Elsevier B.V. All rights reserved.