Renu Rani

Structural, Dielectric, Ferroelectric and Ferromagnetic Properties of Ba0.9Sr0.1ZrxTi1-xO3+ 5% Ni0.8Zn0.2Fe2O4 Composite

The composites consisting of Mn doped Ni0.8Zn0.2Fe2O4 and Zr substituted Ba0.9Sr0.10TiO3 (BST) where Zr varies from 0.00 to 0.16 in steps of 0.04 were prepared by conventional solid state reaction route. The existence of both phases was confirmed by the XRD patterns and the lattice parameters for each composition were calculated. The dielectric parameter such as dielectric constant and dielectric loss were measured as a function of frequency and temperature. As we increase the Zr in ferroelectric phase, the dielectric loss of composite samples decreases up to 1% from 8%, and also Tmax decreases towards room temperature. Observation of ferroelectric and magnetic hysteresis loops for all samples confirms the electric and magnetic nature of the samples.

Dielectric and Ferroelectric Properties of BST and Ni-Zn Ferrite Composites

Ferroelectric—ferrite composites are very important materials as they show both electric and magnetic properties and are drawing attention of researchers over the last few years due to their immense contribution to the improvement of science and technology. Electrical and ferroelectric properties of such ceramic materials are strongly dependent on composition and ratio of two constituents. In the present paper we are reporting the dielectric and ferroelectric properties of (1-x)Ba0.90Sr0.10TiO3- xNi0.80Zn0.20Fe2O4, (0 ≤ x ≤ 0.02 steps of 0.01) (BST-NZF) mixed phase materials. Both the constituent materials were prepared separately by conventional solid state method and then finally mixed by weight to form the mixture. The dielectric properties were measured as a function of temperature at 100 Hz, 1 kHz, 10 kHz and 100 kHz frequencies. P-E hysteresis loops were recorded at 20 Hz for all the mixture samples. Remanent polarization was found to decrease with increase in ferrite content. Magnetization measurements show the samples to be in ferromagnetic state. Structural analysis was done by X-ray diffraction analysis.

Structural, Electrical and Magnetic Properties of Microwave Processed Ni0.80Zn0.20Fe2O4

The material sample was prepared by conventional solid state method and sintered in conventional and microwave furnace at different sintering temperatures. Sintered samples were then subjected to XRD and SEM analysis. X-ray diffraction revealed the formation of single phase material. SEM of fractured cross sectional portion showed that finer grains were formed in case of microwave sintering. The dielectric properties and magnetic properties were recorded for both the samples and both properties were found to improve in microwave sintered samples. There is also a significant improvement in density and magnetic properties by microwave processing.

Influence of Zr Substitution on Ferroelectric Properties of BST Ceramics

Zirconium substituted strontium modified barium titanate ceramics with compositional formula Ba0.9Sr0.1Ti1-xZrxTiO3 (0 ≤ x ≤ 0.16 in steps of 0.04) were prepared by the solid state reaction route. Effects of substitution of Zr4+ on the physical and ferroelectric properties were studied. Decrease in relative density with increase in Zr content was observed. Ceramic sample with 4 mol% Zr showed maximum remnant polarization (11.5 μC/cm2) and coercive field (3.2 kV/cm). Microstructural information collected from scanning electron microscopy (SEM) was found helpful to explain ferroelectric properties.

Effect of Sintering Temperature on Dielectric Properties of Iron Deficient Nickel-Ferrite

Nickel Ferrite among all the magneto ceramic materials have been studied very much due to its large number of applications. But there is a large scope of modification of its properties. Thus people still working on it for improvisation of its properties via compositional and structural modifications. Present paper reporting the preparation and characterization of iron deficient Nickel ferrite for different sintering temperature. Ferrite samples having the general formula NiFe1.98O4 were prepared using the standard ceramic method. The phase formation was confirmed by X‐ray diffraction technique. The effect of sintering temperature on the electrical properties and resistivity was studied. The data shows that dielectric properties are highly dependent on the sintering temperature.

Effect of two-stage sintering on dielectric properties of BaTi0.9Zr0.1O3 ceramics

The effect of two-stage sintering on the dielectric properties of BaTi0.9Zr0.1O3 ceramics prepared by solid state route was investigated and is presented here. It has been found that under suitable two-stage sintering conditions, dense BaTi0.9Zr0.1O3 ceramics with improved electrical properties can be synthesized. The density was found to have a value of 5.49 g cc−1 for normally sintered samples, whereas in the case of the two-stage sintered sample it was 5.85 g cc−1. Dielectric measurements were done as a function of frequency and temperature. A small decrease in the Curie temperature was observed with modification in dielectric loss for two-stage sintered ceramic samples.

Improved Dielectric Properties via Mechano‐Chemical Activation in Ba0.80Pb0.20TiO3 Ceramics

The present report is about the preparation and dielectric properties of commonly used Ba0.80Pb0.20TiO3 (BPT) ferroelectric ceramic via Mechano‐Chemical Activation (MCA). Results were compared by the BPT sample prepared by conventional solid state method. The BPT sample prepared via MCA technique was found to have decreased tetragonality, dielectric constant value (eRT = 450 and emax = 6170) approximately double the value for sample prepared by conventional method (eRT = 260 and emax = 3275). Also, the sample prepared by MCA was found to be less frequency dependent. Thus, the BPT sample prepared via MCA is more suitable for capacitor applications requiring lesser frequency dependency than the conventionally prepared BPT sample.