Structural, magnetic and dielectric properties of Dy-Co substituted Sr-Ba-Mg-based magnetic oxides

In present research six samples of nano X-type hexagonal ferrites with general formula SrBaMg2-xCoxDyyFe28-yO46 (x = 0-1; y = 0-0.1 with step size of 0.2 and 0.02, respectively) were synthesized by sol-gel technique. The temperature required for the phase formation of these materials was estimated using thermogravimetric analysis. X-ray diffraction patterns revealed the pure phase of the prepared materials up to the doping concentration of x = 0.4, y = 0.04 along with the second phase for higher doping concentration. The secondary phase appeared due to the solubility limit of higher ionic radius Dy3+ ions into the hexagonal lattice. The mean crystalline size decreased from 29 to 18 nm while unit cell volume, bulk density, and X-ray density were increased with Dy-Co doping. Hysteresis loops showed that by incorporation of Dy-Co ions the saturation magnetization (M-s) was enhanced from 50 to 60 emu.g(-1). Also, coercivity (H-c) varied in the range 1573-3251 Oe, such high values of M-s and H-c propose the utilization of these X-type materials as permanent magnets and perpendicular recording media. The dependence of dielectric parameters (dielectric constant, ac conductivity, Q-value) on frequency (1 MHz-3 GHz) as well as composition was discussed. Inclusion of Dy-Co in X-type lattice modified dielectric parameters i.e. dielectric constant, ac conductivity was increased. Complex modulus studies directed to elucidate Nyquist plots which exhibited a single half-circle for all X-type ferrites, thus depicting Debye sort of behavior.

Automated summary

Six samples of nano X-type hexagonal ferrites were synthesized by sol-gel technique, with X-ray diffraction patterns revealing pure phase at lower doping concentrations and a second phase at higher concentrations. The incorporation of Dy-Co ions enhanced the magnetic properties, suggesting potential applications in permanent magnets and perpendicular recording media. The study on dielectric parameters indicated that Dy-Co doping increased the dielectric constant and ac conductivity.