Electrical, Magnetic and Dielectric Properties of Cobalt-Doped Barium Hexaferrite BaFe12-xCoxO19(x=0.0, 0.05, 0.1 and 0.2) Ceramic Prepared via a Chemical Route

BaFe12-xCoxO19(BHFC) hexaferrites with compositions (x = 0.0, 0.05, 0.1 and 0.2) were successfully synthesized by a chemical route at 1150 degrees C for 12 h. Single-phase formation for BaFe12-xCoxO19(x = 0.0, 0.05, 0.1) were confirmed by x-ray diffraction (XRD) patterns. However, a small amount of secondary phase of Fe(2)O(3)was found in the case of high-percentage substitution of Co (x = 0.2). Le Bail analysis and transmission electron microscopy (TEM) analysis confirmed the existence of a hexagonal structure in the BHFC ceramics for all the synthesized compositions with lattice parametersa = b = 5.88603 angstrom,c = 23.18299 angstrom and space groupP6(3)/mmc. The average crystallite sizes were found to be 41.48 nm, 39.02 nm, 35.99 nm and 33.56 nm, respectively, using the Debye-Scherer equation. The Fourier transform infrared (FTIR) spectrum was recorded in the frequency range of 5000-400 cm(-1)at room temperature to explain the presence of M-O such as Fe-O, Ba-O and Co-O bonds and Fe-O-Fe (M-O-M) bonds in BHFC ferrites. The presence of M-O and M-O-M bonds was also confirmed by the phase formation of hexagonal ferrites. The hexagonal plate-like structure was observed using scanning electron microscopy (SEM). BHFC ceramics displayed average grain size 0.50 mu m, 0.84 mu m and 1.0 mu m for the compositions (x = 0.0, 0.05 and 0.1), respectively. Magnetic, dielectric and AC conductivity measurements were carried out using a vibrating-sample magnetometer (VSM) and impedance analyzer, respectively. The saturation magnetization (M-s) of the BHFC ceramic observed by magnetic measurements was lower than pure barium hexaferrite materials. The value of the dielectric constant (epsilon) for the BHFC ceramic was found to be 2.3 x 10(3)at 100 Hz.