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Polycrystalline ceramics, Bi1-2xBa2xFe1-xNbxO3 (x = 0.00–0.15), were synthesized by solid state reactions method. X-ray diffraction data have revealed elimination of impurity phases and an increase in unit cell volume with Ba and Nb substitution. Diffraction peak splitting is found to be suppressed which indicates a decrease in octahedral distortion. The Mössbauer spectra demonstrate the suppression of spiral spin modulation of the magnetic moments resulting in enhanced ferromagnetism with increasing dopant concentration. The leakage current density of the sample with x = 0.10 is found to be greatly reduced up to six orders of magnitude as compared to the undoped sample. Ohmic conduction is found to be dominant mechanism in all the samples, however, undoped sample showed space charge limited conduction in high electric filed region, while the sample with x = 0.15 exhibited grain boundary limited conduction in low electric field region.

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M-type hexaferrites has attracted researchers due to their ordinary magnetic properties and utilization as media for magnetic recording and microwave devices. In this study we have synthesized Ba0.5Sr0.5Fe9Ce1Al2O19 via conventional ceramic route. The synthesized material is treated against different temperatures and investigated structurally and magnetically by using several techniques such as X-ray diffraction, Scanning electron microscopy, and VSM respectively. Morphology of samples confirms the absence of secondary phases and uniform distribution of particles. X-ray diffraction patterns confirms the formation of pure phase of Hexaferrites. Microstructural analyses show the decrease in porosity and dislocations among sintered samples. Magnetic properties for the samples show a decrease in Ms and Mr with increasing temperature from 1225 °C to 1310 °C, while coercivity shows an increase with increasing temperature and maximum coercivity is observed at 1290 °C. The trends and occurrences can be well-linked to the structural variations and sintering effects. The results suggest that material can be used in various magnetic applications such as Recording media, and memory devices.

The electrical transport properties of MgAl2−xCoxO4 (where x = 0.0, 0.5, 1.0, 1.5, 2.0) were investigated at room temperature. The dielectric behavior of the samples, and the contribution of the grains and the grain boundary regions to the electric response of the samples were observed using impedance spectroscopy in the frequency range of 20 Hz to 2 MHz. The DC conduction behavior was studied by measuring current density J against electric field E. It was observed that the grains and grain boundaries both contribute equally to the variation in electric response caused by changing the dopant concentration of cobalt in MgAl2O4. The combined Z″ and M″ spectroscopic plots indicated the presence of small polaron hopping conduction in the grain region of the samples. Moreover, the 25% doped sample showed minimum conductivity among all samples, which was two orders of magnitude less than that of the pure sample.