Abstract
Nano-crystalline Gd–Co substituted X-type hexagonal ferrites having formula SrBaMn2-xCoxGdyFe28-yO46 (where x = 0–1, y = −0.1) were synthesized employing sol-gel route. X-ray diffraction technique verified the formation of pure phase X-type ferrites for all samples. Crystallite size was reduced from 27.49 to 24.52 nm with Gd–Co concentration, which is favorable for attaining an appropriate signal-to-noise ratio in electronic devices. Lattice constants (a, c), bulk, and X-ray density slightly increased owing to the large ionic radius and density of Gd3+ ions than Fe3+ ions. Fourier transform infra-red spectroscopy displayed absorption bands in the lower wavenumber range (482-584 cm−1). The higher absorption bands (482-584 cm−1) are due to metal-oxygen vibration octahedral and tetrahedral sites. The influence of Gd–Co on dielectric properties such as dielectric constant, tangent loss, ac conductivity, and Q-value on frequency and composition were investigated in the frequency region of 1 MHz–3 GHz. The incorporation of Gd–Co resulted in the enhancement of dielectric properties of as-prepared X-type materials desired in electromagnetic devices operating at microwave frequencies. Electric modulus analyses indicated the contribution of grain boundary towards resistance.