Microstructural, Thermal, Magnetic And Dielectric Properties Of Cobalt Doped Barium Calcum Hexaferrite Prepared By A Sol-Gel Route

Abstract

A series of w-type hexagonal ferrites with the composition BaCoxCa2-xFe16O27 (x = 0.4, 0.8, 1.2, 1.6, 1.8 and 2.0) were synthesized using a Stearic acid gel route with and without presence of Cetyletrimethyle ammonium bromide. The precursors were calcinated at 950ºC for 4 hrs in a furnace and then slowly cooled to room temperature in order to obtained BaCoxCa2-xFe16O27 crystalline ferrite powder. The effect of cationic surfactant Cetyletrimethyle ammonium bromide (CTAB) on structural and thermal properties were studied. The structural properties of the samples were studied by using XRD, FTIR and SEM. Decomposition behavior is investigated by means of thermal analysis (TGA). Thermo gravimetric analysis confirms the high thermal stability of w-type hexagonal ferrite particles synthesized in presence of CTAB. The field dependent magnetic properties of prepared Ba-Ca hexaferrite particles were investigated at room temperature by using Vibrating Sample Magnetometer (VSM). The maximum coercivity and saturation magnetization of prepared w-type hexaferrite samples were determined by a VSM. The value of saturation magnetization depends on amount of cobalt substitution. The sample (x = 0.8) shows high saturation magnetisation (~71 emu/g), where as the sample (x = 2.0) exhibits low saturation magnetisation (~65 emu/g). Magnetic study reveals that prepared BaCoxCa2-xFe16O27 (x = 1.8 and 2.0) hexaferrite particles prepared in presence of CTAB possess single magnetic domain.The dielectric measurements were carried out at room temperature between the frequency range 100 Hz to 1 MHz.