Structural, Magnetic and Electrical Properties of Ba_2Mg_2Fe_(28)O_(46) (Mg_2X) hexaferrites

摘要

X-type barium hexaferrite having the formula Ba_2Mg_2Fe_(28)O_(46) (Mg_2X) were prepared by sol-gel autocombustion method. The combusted powder calcined at different temperature for one hour. The effects of the annealing temperature on the structural, magnetic and electrical properties of the samples studied by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), vibrating sample magnetometry (VSM) and LCR-meter. XRD results confirmed the formation of X-type barium hexaferrite with presence of secondary phases such as M and W phases at 1200°C and 1250°C but, single phase of X-type at 1300°C. Avearage crystallite size calculated by Scherer formula and showed it is equal 43.397 nm at 1300°C. FESEM images show platelet-like particles for X-type with average grain size about 1.154μm. Hysteresis loop measurements showed the values of the saturation magnetizations, remanence and coercivity at 1300°C about 50.656 emu/g, 18.416 emu/g and 505.330 Oe respectively. The dielectric constant, tangent loss and ac conductivity calculated as a function of frequency in the range of 100Hz to 3MHz for the samples sintered at 1200°C, 1250°C and 1300°C and showed that the dielectric parameters decrease with increasing frequency and increase with increasing temperature but the ac conductivity increases with increasing frequency and temperature and showed semiconducting like behavior with increasing temperature. Then concludes that high dielectric parameters and coercivity about 505.330 Oe at 1300°C made this material used in the fabrication of multilayer chip inductors (MLCI's) circuits.