Structural and impedance spectroscopy study of Samarium modified Barium Zirconium Titanate ceramic prepared by mechanochemical route

T. Badapanda,S. Sarangi,B. Behera,S. Anwar 한국물리학회 2014 Current Applied Physics Vol.14 No.9

Samarium modified Barium Zirconium Titanate (BZT) ceramics with general formula [Ba1xSm2x/ 3](Zr0.05Ti0.95O3) [x ¼ 0, 0.01, 0.02, 0.03 and 0.04] have been prepared by high energy ball milling. The Rietveld refinement of BaZr0.05Ti0.95O3 (BZT) shows a single phase tetragonal symmetry with space group P4mmm and TEM micrograph shows that the crystalline size is in the submicron range. X-ray diffraction (XRD) patterns confirm that no phase change occurs with the addition of Samarium in BZT upto x 0.03 and a small pyrochlore phase exists at x ¼ 0.04. The complex impedance (Nyquist) plots display a single semicircle highlighting the influence of grain resistance on the electrical behavior. Negative temperature coefficient of resistance behavior is observed in all compositions. The activation energy calculated from Z00 and DC conductivity confirms that the oxygen vacancies play an important role in the conduction mechanism.

Rietveld refinement, microstructure, conductivity and impedance properties of Ba[Zr_0.25Ti_0.75]O_3 ceramic

T. Badapanda,V. Senthil,S.K. Rout,L.S. Cavalcante,A.Z. Simões,T. P. Sinha,S. Panigrahi,M.M. de Jesus,E. Longo,J.A. Varela 한국물리학회 2011 Current Applied Physics Vol.11 No.6

In this work, we report the Rietveld refinement, microstructure, conductivity and impedance properties of Ba[Zr_0.25Ti_0.75]O_3 ceramic synthesized by solid state reaction. This ceramic was characterized by X-ray diffraction, Rietveld refinement, scanning electron microscopy and energy dispersive X-ray spectrometry. Impedance spectroscopy analyses reveals a non-Debye relaxation phenomenon being its relaxation frequency moving toward to positive side with increase of temperature. A significant shift in impedance loss peaks toward higher frequency side indicates conduction in material and favoring the long range motion of mobile charge carriers. The frequency dependent ac conductivity at different temperatures indicates that the conduction process is thermally activated. The variation of dc conductivity exhibited a negative temperature coefficient of resistance behavior. The ac conductivity data are used to evaluate the density of states at Fermi level and activation energy of this ceramic. The dc electrical and thermal conductivities of grain and grain boundary have been discussed.

Phase formation and dielectric study of Bi doped BaTi0.75Zr0.25O3 ceramic

T. Badapanda,S.K. Rout,S. Panigrahi,T.P. Sinha 한국물리학회 2009 Current Applied Physics Vol.9 No.4

Perovskite types Ba1-xBi2x/3Ti0.75Zr0.25O3 (with x = 0.0, 0.025, 0.05) ceramics have been prepared through solid state reaction route. The room temperature XRD study suggests that all the compositions have single phase cubic symmetry with space group Pm-3m. Temperature dependent dielectric studies of the ceramics have been investigated in the frequency range of 50 Hz–1 MHz. The densities of the samples are determined using Archimedes’ principle and found to be ~98% of X-ray density. The dielectric study revealed diffuse phase transition of second order. A broad dielectric anomaly coupled with the shift of dielectric maxima toward a higher temperature with increasing frequency indicates the relaxor-type behavior in the ceramics. The diffusivity increases with increase in Bi contents in the studied composition range. The transition temperature decreases with increase in Bi contents due to the decrease in grain size. Perovskite types Ba1-xBi2x/3Ti0.75Zr0.25O3 (with x = 0.0, 0.025, 0.05) ceramics have been prepared through solid state reaction route. The room temperature XRD study suggests that all the compositions have single phase cubic symmetry with space group Pm-3m. Temperature dependent dielectric studies of the ceramics have been investigated in the frequency range of 50 Hz–1 MHz. The densities of the samples are determined using Archimedes’ principle and found to be ~98% of X-ray density. The dielectric study revealed diffuse phase transition of second order. A broad dielectric anomaly coupled with the shift of dielectric maxima toward a higher temperature with increasing frequency indicates the relaxor-type behavior in the ceramics. The diffusivity increases with increase in Bi contents in the studied composition range. The transition temperature decreases with increase in Bi contents due to the decrease in grain size.

Dielectric Behavior of Yttrium doped Barium-zirconium-titanate Ceramics

T. Badapanda,S. Panigrahi,T. P. Sinha,우성일,S. K. Rout 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.55 No.2

The ferroelectric behavior of the yttrium-doped barium-zirconium-titanate perovskite ceramics Ba1−xY2x/3Ti.75Zr0.25O3 (with x = 0.0, 0.01, 0. 025, 0.05) has been studied. The room temperature X-ray diffraition study suggests that all the compositions have a single-phase cubic symmetry with space group Pm-3m The temperature dependent dielectric constant of the ceramics was investigated in the frequency range from 50 Hz to 1 MHz. The density of the samples was determined using Archimedes’ principle and was found to be ~98% of the X-ray density. A broad dielectric anomaly coupled with a shift of the dielectric maximum towards a higher temperature with increasing frequency indicates relaxor-type behavior in the ceramics With increasing in yttrium content, the Curie temperature decreased, except for x = 0.01 where the Curie temperature increased. The relative permittivity decreased and broadened with increasing yttrium content.

Structural and dielectric properties of polyvinyl alcohol/barium zirconium titanate polymereceramic composite

T. Badapanda,V. Senthil,S. Anwar,L.S. Cavalcante,N.C. Batista,E. Longo 한국물리학회 2013 Current Applied Physics Vol.13 No.7

The polyvinyl alcohol (PVA)/barium zirconium titanate Ba[Zr0.1Ti0.9]O3 (BZT) polymereceramic composites with different volume percentage are obtained from solution mixing and hot-pressing method. Their structural and electrical properties are characterized by X-ray diffraction (XRD), Rietveld refinement,cluster modeling, scanning electron microscope and dielectric study. XRD patterns of PVA/BZT polymereceramics composite (with 50% volume fractions) indicate no obvious differences than the XRD patterns of pure BZT which shows that the crystal structure is still stable in the composite. The scanning electron micrograph indicates that the BZT ceramic is dispersed homogeneously in the polymer matrix without agglomeration. The dielectric permittivity (εr) and the dielectric loss (tan d) of the composites increase with the increase of the volume fraction of BZT ceramic. Theoretical models are employed to rationalize the dielectric behavior of the polymer composites. The dielectric properties of the composites display good stability within a wide range of temperature and frequency. The excellent dielectric properties of these polymereceramic composites indicate that the BZT/PVA composites can be a candidate for embedded capacitors.

Structural refinement, optical and ferroelectric properties of microcrystalline Ba(Zr0.05Ti0.95)O3 perovskite

T. Badapanda,S. Sarangi,B. Behera,P.K. Sahoo,S. Anwar,T. P. Sinha,G.E. Luz Jr.,E. Longo,L.S. Cavalcante 한국물리학회 2014 Current Applied Physics Vol.14 No.5

For this study, a microcrystalline Ba(Zr0.05Ti0.95)O3 (BZT) powder was prepared by a high energy ball milling method followed by calcination at 1100 C for 4 h. The calcined powder was structurally characterized by X-ray diffraction and Rietveld refinement data, which showed that this material has a perovskite-type tetragonal structure with a space group of (P4mmm). The micro-Raman spectrum revealed local lattice distortions due to distorted octahedral [TiO6] clusters. The temperature and frequency-dependent dielectric study of the BZT ceramic showed normal phase transition behavior. The ferroelectric property was studied by a PeE hysteresis loop. Optical band gap was investigated by ultravioletevisible (UVevis) absorption spectroscopy at room temperature. The UVevis spectrum indicated that the BZT powder has an optical band gap of 3.15 eV.

Investigation of Structural, Photoluminescence and Thermoluminescence Properties of Scheelite-Type CaWO 4 Phosphor

R. Paikaray,T. Badapanda,H. Mohapatra,T. Richhariya 한국전기전자재료학회 2023 Transactions on Electrical and Electronic Material Vol.24 No.1

This paper reports structural, optical, photoluminescence and thermoluminescence properties of scheelite-type CaWO 4 ceramic synthesized by solid-state reaction route. X-ray diffraction study revealed the structure of the sample with tetragonal phase and I4 1 /a (88) space group. Lattice parameters were calculated from the Rietveld refi nement method and the crystal structure was observed using VESTA software. Photoluminescence excitation spectra were obtained by using 450 nm and 460 nm emission wavelengths. The emission spectra obtained with 240 nm excitation wavelength showed an emission band around 448 nm that can be ascribed to 1 T 2 to 1 A 1 optical transition of electrons within [WO 4 ] 2- group. CIE Chromaticity indicated that CaWO 4 emits blue color and the color purity is also calculated. Optical band gap and urbach energy of the material were measured from the UV-visible spectroscopy. Thermoluminescence (TL) properties were investigated with different UV doses and the variations of TL emission peaks with temperature confirmed that CaWO 4 has second-order kinetics with lower UV dosimetry.

Investigation of structure–property correlation on the dielectric and optical properties of lanthanum modified barium titanate ceramic

Mahapatra A. K.,Badapanda T.,Sahoo S.,Sarangi S. 한국세라믹학회 2022 한국세라믹학회지 Vol.59 No.6

The present manuscript outlines the investigation of the structure, dielectric and optical properties of Lanthanum (La) doped BaTiO 3 (BLT) ceramic with compositions of Ba 1-xLa2x/3TiO 3 prepared by the solid-state reaction method. The Rietveld refi nement of the XRD pattern illustrates that La doping changes from tetragonal structure to cubic structure with a mixed phase in intermediate composition. The Raman spectra illustrate the existence of modes associated with tetragonal symmetry up to x = 0.05 and the disappearance of modes at 307  cm −1 confi rming the cubic symmetry for higher doping concentration. The temperature variant dielectric study in the studied range reveals a two-phase transition until x = 0.05 which merges for higher concentrations. The temperature variant dielectric study expresses that the transition temperature declines whereas the dielectric constant at transition temperature increases as a function of doping content. The dielectric loss of the doped samples is found to increase until x = 0.05 and thereby decreases for higher concentration values. The temperature coeffi cient of the dielectric constant was calculated for all the compositions. The diff usivity was calculated using the altered Curie–Wiess law revealing that the diff usivity increases because of doping percentages. A signature of relaxor nature is obtained in the composition x = 0.1, which is confi rmed by the Vogel–Fulcher (VF) fi tting. The optical property of all the prepared samples has been studied using UV–Vis spectroscopy and photoluminescence.

Investigation of thermal energy potential, pyroelectric, and electrocaloric performance of Ba0.7Ca0.3TiO3 ceramic

Ray A.,Nayak B.,Elorika P.,Barman R.,Sharmistha A.,Badapanda T.,Anwar S. 한국세라믹학회 2023 한국세라믹학회지 Vol.60 No.5

In the current work, the structural, dielectric, and electrocaloric performance of Ba0.7Ca0.3TiO3 ceramic synthesized by solid-state reaction route is presented. The structural analysis was examined by X-ray diffraction and Rietveld refinement, which confirms the existence of a combined phase of tetragonal structure with P4mm symmetry and orthorhombic structure with Amm2 symmetry. The scanning electron micrograph shows well-defined and pore-free grains. The temperature-dependent dielectric performance shows diffuse phase transition behavior. The temperature-dependent ferroelectric hysteresis behavior was examined under the application of various amplitudes of an applied electric field. The energy storage density, energy loss density, and energy storage efficiency of the composition at different temperature were calculated using the standard formula. The thermal energy potential has been calculated by employing the Olsen cycle. Also, pyroelectric figures of merit (FOMs) for voltage responsivity (Fv), current responsivity (Fi), energy harvesting (Fe), new energy harvesting (F*e), and detective (Fd) were calculated. Adiabatic temperature change, isothermal entropy change, and electrocaloric strength are evaluated using an indirect technique based on the thermodynamic Maxwell's relation.