In the present study, a series of Cu substituted M type Barium hexagonal ferrite BaCuxFe12-xO19 (x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0) has been synthesized using a Sol- gel auto combustion method. The aim of the present work was to investigate the effects of Cu/Fe ratio on the crystallography and dielectric properties. The XRD studies reveal a formation of the single phase BaFe12O19 at the initial level and mixed phase of S, M and Y hexaferrite at the higher level of copper substitution. The dielectric measurements were carried out at room temperature in a frequency range of 20 Hz to 2MHz. the dielectric constant is found to decrease with the increase of frequency for all the compositions.

M-type barium hexagonal ferrite (BaFe 12 O 19 ) has been synthesized by sol-gel auto combustion method. The synthesized material was irradiated with 200 MeV Ag 16+ ions using the 15UD Pelletron tandem accelerator and the changes in structural and surface morphology of material were investigated. The pristine (as-synthesised) and irradiated samples were characterized using different experimental techniques like x-ray diffraction (XRD), Fourier-transform infrared spectroscopy, transmission electron microscope (TEM) and vibrating sample magnetometer (VSM). The strong absorption peak between 580 and 440 cm −1 in the infrared spectrum and XRD confirmed the formation of ferrite structure for both irradiated and pristine samples. XRD peaks for the irradiated barium hexagonal ferrite were slightly broadened when compared pristine ferrite samples. The crystallite size of the irradiated barium hexagonal ferrite was higher than that of pristine barium hexagonal ferrite and is consistent with TEM images. Both saturation magnetization and coercivity were decreased with irradiation.

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Cobalt ferrite (Cofe2o4) particles were synthesized with and without presence of surfactants using a co-precipitation method. Three surfactants Cetyl Tri methyl Ammonium Bromide (CTAB-cationic), Sodium dodecylbenzenesulphonate (anionic), Triton X-100 (nonionic), were used and investigate their effects on the structural and dielectric properties of CoFe2O4 particles. The ferrite precursors were first pre calcined in a muffle furnace at 500°C and then calcined at 950°C. Structural, dielectric and magnetic properties of prepared particles were investigated using X-ray powder diffraction, Dielectric and Low field ac magnetic susceptibility measurement. Phase purity of prepared samples was confirmed by X-ray diffraction. The sample with surfactant Triton X-100 shows the highest values of dielectric constant at low frequency.

Z-type hexaferrite with composition Ba3Co2Fe24O41has been synthesized using a sol-gel auto combustion technique. The obtain combusted powder was sintered at 500 OC and followed by 950 OC for 4 hrs in a muffle furnace. The effect of different sintering temperature on crystal structure, crystallite size, microstructure and dielectric properties were systematically investigated. The prepared barium cobalt hexaferrite powder samples were characterized using different experimental techniques like FTIR, XRD, AC conductivity and specific magnetization measurements. It was observed from XRD results that heat treatment conditions play significant role in the formation of hexaferrite phase. AC conductivity measurements were carried out at room temperature in frequency range of 20Hz to 2MHz. All the samples show the frequency dependent phenomena, i.e. the AC conductivity increases with increasing frequency.