Poonam Kumari

Study the Structural and Dielectric Properties of Rare-Earth La Doped (Ba1-xLax) (Ti0.815Mn0.0025Nb0.0025Zr0.18)0.995O3 Ceramics

The ferroelectric La doped (Ba1-xLax) (Ti0.815Mn0.0025Nb0.0025Zr0.18)0.995O3 (BLTMNZ) (where x = 0.04, 0.10 and 0.20) ceramics were prepared by using the solid state reaction method. The powders in the suitable stoichiometric ratio of the compositions were weighed and mixed thoroughly in acetone and calcined at 900°C for 12h in high temperature muffle furnace. Phase identification of ceramics was carried out in 2θ range of 20°-60° using X-ray diffraction technique. XRD pattern of the samples indicated that the compositions have an orthorhombic structure at room temperature. The average crystallite size of the BLTMNZ particle was found near 30nm. The ferroelectric phase-transition of BLTMNZ materials was studied by using dielectric measurements at different temperature. Dielectric constant and tanδ of the specimens was measured in the temperature range from 23°C to200°C at frequencies 1 kHz-1 MHz. The temperature dependence of dielectric measurement of lanthanum doped BLTMNZ samples indicate that the phase transition shifts towards low temperature with increasing La content. The value of diffusivity (γ) indicates that the compounds exhibit a diffuse type of phase transition. The ac conductivity was decreases with the increasing the frequency.

Dielectric, electrical conduction and magnetic properties of multiferroic Bi0.8Tb0.1Ba0.1Fe0.9Ti0.1O3 perovskite compound

This work focuses on the structural, electrical and magnetic properties of Bi0.8Tb0.1Ba0.1Fe0.9Ti0.1O3 ceramics, fabricated by solid state reaction procedure. XRD forms of the samples at RT exhibited perovskite phase through the hexagonal structure at room temperature. Dielectric studies of the materials with frequency at different temperatures (25–400∘C) exhibit two dielectric anomalies, first at 175∘C (ferroelectric–ferroelectric transition) and second at around 320∘C (ferroelectric–paraelectric transition). The Curie temperature moved towards the low side temperature with the increase in frequency. The less value of activation energy got for these samples could be attributed to the influence of electronic contribution to the conductivity. A significant change in the magnetic studies was observed for Bi0.8Tb0.1Ba0.1Fe0.9Ti0.1O3 ceramic. The impedance analysis confirms the non-Debye type nature of the ceramic and relaxation frequency moved to a higher temperature. The Nyquist plot and conductivity studies showed the NTCR behavior of samples. The highest magnetization field was found at temperature −268.15∘C.

Study the structural and magnetic properties of rare-earth ions (La and Gd) doped Ba0.9575Ca0.0025Ti0.80685Mn0.002475Nb0.002475Zr0.1782O3 (BCTMNZ) ceramics

In this paper, we investigated the influence of rare earth (RE=La and Gd) doped Ba0.9575RE0.04Ca0.0025Ti0.80685 Mn0.002475Nb0.002475Zr0.1782O3 (BCTMNZ) ceramics were fabricated by using a conventional solid-state reaction method. The doping effects of La and Gd on the structural and magnetic properties were studied. The structural pattern of the ceramic samples were investigated by X-ray diffraction and the results indicated that both samples shows an orthorhombic structure with pure phase. Strain and crystalline size values for Gd and La doped were 0.31–0.33% and 0.154–0.181μm, respectively. The room temperature hysteresis loops were obtained by using a vibrating sample magnetometer. La doped ceramic showed the higher value of magnetization i.e., 0.369μB/f.u. as compared to Gd doped BLTMNZ ceramics.