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M-type barium hexaferrite ceramics (BaM) are important materials owing to their tremendous applications and useful properties. However magnetic and electrical properties of Cu substituted BaM haven’t been studied yet. In the present study, Cu doped BaM samples having chemical formula BaFe12−xCuxO19 (where x = 0, 0.1, 0.3 and 0.5) were synthesized by conventional solid state mixed oxide route. X-ray diffraction and Fourier transform infrared spectroscopy confirmed the formation of hexagonal magnetoplumbite structure with space group P63/mmc as the major phase in all the samples. Scanning electron microscopy revealed the dense structure of undoped and doped samples with platelet-like morphology. Vibrating sample magnetometry showed a large decrease in the coercivity of BaM without the loss of saturation magnetization by the addition of Cu. Magnetic measurement at cryogenic temperature (25 K) revealed that Cu doped sample showed less variation in magnetic properties on decreasing the temperature as compared to undoped BaM samples. Room temperature dielectric studies showed that addition of Cu caused a decrease in dielectric loss however it increased at higher substitution level i.e. x = 0.5. High temperature conductivity studies revealed that single-ionized oxygen vacancies are responsible for conduction in Cu doped BaM. [ABSTRACT FROM AUTHOR]

Polycrystalline barium hexaferrites BaFeNiO ( x = 0, 0.3 and 0.5) ceramics were synthesized by the conventional solid state route. X-ray diffraction and Fourier transform infrared spectroscopy studies confirmed the successful substitution of Ni in BaFeO without the formation of any additional phase. Scanning electron microscopy images showed a platelet-like morphology of particles with an increase of average grain size by the increase in Ni content. A vibrating sample magnetometer revealed that the remnant magnetization M and coercivity H increased to a large extent, i.e., from 20.24 to 25.51 emu/g and from 1027.20 to 1971.60 Oe, respectively, with the increase in Ni from x = 0 to x = 0.5; however, saturation magnetization M showed a minor variation. Dielectric studies were done using a precision impedance analyzer, which showed a decrease in dielectric loss with the increase in Ni content and very little variation in the conductivity of the samples. [ABSTRACT FROM AUTHOR]

M-type barium hexaferrite ceramics have emerged as important materials both for technological and commercial applications. However, limited work has been reported regarding the investigation of nanocrystalline Ni-doped barium hexaferrites. In this study, nanocrystalline barium hexaferrite ceramics with the composition BaFe12−xNixO19 (where x = 0, 0.3 and 0.5) were synthesized by sol-gel method and characterized using X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, vibrating sample magnetometer and precision impedance analyzer. All the synthesized samples had single magnetoplumbite phase having space group P63/mmc showing the successful substitution of Ni in BaFe12O19 without the formation of any impurity phase. Average grain size of undoped samples was around 120 nm which increased slightly with the addition of Ni. Saturation magnetization (Ms) and remnant magnetization (Mr) increased with the addition of Ni, however, coercivity (Hc) decreased with the increase in Ni from x = 0 to x = 0.5. Real and imaginary parts of permittivity decreased with the increasing frequency and increased with Ni content. Dielectric loss and conductivity showed slight variation with the increase in Ni concentration. [ABSTRACT FROM AUTHOR]