Dr.Santiranjan Shannigrahi - Academia.edu (original) (raw)

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Papers by Dr.Santiranjan Shannigrahi

An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Journal of Magnetism and Magnetic Materials, Nov 1, 2018

Journal of Magnetism and Magnetic Materials, Nov 1, 2017

Journal of Applied Physics, 2007

Ferroelectric (Pb0.97,La0.03)(Zr0.52,Ti0.48)O3 thin films in different thicknesses were fabricate... more Ferroelectric (Pb0.97,La0.03)(Zr0.52,Ti0.48)O3 thin films in different thicknesses were fabricated on Pt∕Ti∕SiO2∕Si substrates through a sol-gel process. Film thickness dependence of photoinduced current was investigated under the illumination of ultraviolet light. A theoretical model was developed to describe the thickness-dependent photocurrent. Both the theoretical model and experimental results showed that the photocurrent increases exponentially with the decrease in film thickness. However, photocurrent may drop in the films with the very small thickness of tens of nanometers and below in which the small size effect of ferroelectricity is considered. This model also reveals the relationship between the photocurrent and the internal electric field or remnant polarization and predicts a small diffusion current in the opposite direction at very low field or polarization region. These results provide useful guides for the design of ferroelectric film photovoltaic devices.

Journal of Material Sciences & Engineering, Oct 1, 2015

T recent emergence of efficient organic/inorganic lead halide perovskite compounds which are easy... more T recent emergence of efficient organic/inorganic lead halide perovskite compounds which are easy to fabricate, have better stability, and possess superior power conversion efficiency have shown the potential to transform photo-voltaics technology. These are very promising in transforming the fields of dye-sensitized, organic, and thin film solar cells. In this research, a versatile solution-processing method called “Spray+Brush” (SB) has been adopted to achieve a power-conversion efficiency of 3.52% for photo-voltaics by incorporating organo-metal halide perovskite absorbers. It has been observed that this method is more efficient and cost effective than the perovskite devices fabricated by spray (1.95%) and brush (1.17%) methods when used alone. The SB method of solution processing can be promising for various other organic coatings.

Journal of Materials Research, Aug 1, 2002

ABSTRACT

Solid State Sciences, Apr 1, 2015

ABSTRACT The electronic structure and optical properties of RAlO3 (R = Sm, Nd) have been investig... more ABSTRACT The electronic structure and optical properties of RAlO3 (R = Sm, Nd) have been investigated by full potential linearized augmented plane wave method within the framework of density functional theory in its generalized gradient approximation. The calculations are initiated with the experimental lattice constants obtained by the Rietveld refinement of the XRD data of the synthesized samples. The band gaps of the systems are measured from the UV-visible reflectance spectra using the Kubelka-Munk function and compared with the calculated data. The spin-polarized calculation has been carried out with on-site Coulomb potential U to consider the electron-electron correlation in the system. The x-ray photoemission spectra (XPS) of the systems are measured. The valence-band density-of-states spectra are generated and compared with the XPS spectra. The chemical shifts of these compounds suggest a mixed ionic and covalent character of the bonds. It has been observed that f-state of Nd and Sm hybridizes with O-2p state near the Fermi level in valence band. The Born effective charge tensors of the constituent ions for SmAlO3 and NdAlO3 have also been calculated which shows strong hybridization and charge transfer between Sm and O in SmAlO3 and Nd and O in NdAlO3. The calculated static dielectric tensor is found to be in good agreement with the experimental values.

Journal of Applied Physics, Oct 4, 2016

Solid State Sciences, Aug 1, 2016

Abstract The structural and magnetic properties of a double perovskite oxide Ba 2 CeSbO 6 (BCSO) ... more Abstract The structural and magnetic properties of a double perovskite oxide Ba 2 CeSbO 6 (BCSO) synthesized by solid state reaction technique have been investigated. The Rietveld refinement of the X-ray diffraction pattern of BCSO suggests the monoclinic crystal structure at room temperature with P2 1 /n space group. The vibrational properties of BCSO are investigated by the Fourier transform Infrared and Raman spectroscopy. The Raman spectrum confirms the B-site ordering of cations in BCSO. The temperature dependent magnetic susceptibility data in the field cooled mode show the anti-ferromagnetic behaviour of BCSO below 59 K. The core level X-ray photoemission (XPS) spectrum of Ce-3d and Sb-3d states confirms the presence of multiple oxidation states of these cations. The presence of both the Ce 3+ and Ce 4+ ions in BCSO gives the 4f 4−δ intermediate valence state which may reduce the effective magnetic moment with respect to the system having single valence Ce 3+ ion.

Inorganic Chemistry, Oct 29, 2012

Applied Physics Letters, Feb 23, 2005

Pb 0.97 La 0.03 ( Zr 0.52 Ti 0.48 ) O 3 + x WO 3 at % (x=0, 0.2, 0.5, 1, and 2) (PLWZT) thin film... more Pb 0.97 La 0.03 ( Zr 0.52 Ti 0.48 ) O 3 + x WO 3 at % (x=0, 0.2, 0.5, 1, and 2) (PLWZT) thin films are deposited on Pt–Ti–SiO2–Si substrates using a sol-gel process. We demonstrate that WO3 dopant plays a significant role on the structure and electrical properties of the PLWZT films. X-ray diffraction (XRD) analyses show that the PLWZT films undergo a dramatic tetragonal–to–cubic crystalline phase transformation with a small amount of WO3 additives. X-ray photoelectron spectroscopy (XPS) study shows that the chemical state of W changes with varying concentration of WO3 in the films. Moreover, PLWZT films with a small amount of WO3 doping (0.2 at %) show a decreased conductivity with an improved remnant polarization value of 30μC∕cm2. In addition, compared to the base (PLZT) film, such doping concentration also leads to significantly improved fatigue characteristics. A defect chemistry mechanism indicating the reduction of oxygen vacancies by the substitution of W for Ti at different doping concentrations has been proposed to explain the observed experimental results.

Journal of Physics and Chemistry of Solids, May 1, 1998

Advanced Materials Interfaces, Nov 13, 2013

Ceramics International, 2011

Thin Solid Films, Jun 1, 2013

ABSTRACT Thin layers of Pb(Zr0.95Ti0.05)O3/Co ferrite (CFO) were deposited on Si(100)/SiO2/Ti/Pt(... more ABSTRACT Thin layers of Pb(Zr0.95Ti0.05)O3/Co ferrite (CFO) were deposited on Si(100)/SiO2/Ti/Pt(111) and SrTiO3(001) substrates using pulsed laser deposition technique. The phase and structural evolutions of the composites were characterized using X-ray diffractometry and transmission electron microscope. The magnetic and electric properties of the samples were evaluated by the hysteresis loop measurement systems. The results showed that the double layer of Pb(Zr0.95Ti0.05)O3/CFO coating on SrTiO3 substrate, exhibited a clear magnetic hysteresis loop as well as a saturated polarization. Magnetoelectric coefficient of this sample (αE) reaches to 244 × 10− 3 V/A (194 mV/cm Oe). Thin layer of Pb(Zr0.95Ti0.05)O3/CFO on Si(100)/SiO2/Ti/Pt(111) substrate was polycrystalline without texture and its maximum magnetoelectric coefficient was 167 × 10− 3 V/A.

Journal of Applied Physics, Aug 1, 2005

Lanthanum-modified lead zirconate titanate Pb0.97La0.03(Zr0.52Ti0.48)O3 doped with xat.% WO3 (x=0... more Lanthanum-modified lead zirconate titanate Pb0.97La0.03(Zr0.52Ti0.48)O3 doped with xat.% WO3 (x=0, 0.2, 0.5, 1, and 2) (PLWZT) ferroelectric thin films have been deposited on Pt∕Ti∕SiO2∕Si substrates using a sol-gel spin-coating process. We have demonstrated that WO3 dopant plays a significant role on the structure and electrical properties of the PLWZT films. The x-ray-diffraction analysis shows that the PLWZT films undergo a dramatic tetragonal-to-cubic crystalline phase transformation with small amount of WO3 additives. Surface morphology (atomic force microscopy) analysis shows that the average grain size decreases with the increase of WO3 doping amount in the PLWZT films. The highest average grain size of 91nm has been observed for PLWZT (WO3:0.2at.%). It is also observed from x-ray photoelectron spectroscopy study that W varies its chemical state with the varying concentration of WO3 in the films. Moreover, the polycrystalline PLWZT thin films with a small amount of WO3 doping (0.2at.%) show a reduced electrical conductivity, improved dielectric constant (ε) (1675 at 1kHz) and decreased dielectric loss (D) (0.03 at 1kHz), and improved remnant polarization (Pr) value of 30μC∕cm2 along with significantly improved fatigue resistance (∼5% attenuated after 108 switching cycles) compared with the other PLWZT films. A defect chemistry mechanism indicating the reduction of oxygen vacancies by the substitution of W for Ti at different doping concentrations has been proposed to well explain the observed experimental results.

Materials Chemistry and Physics, Aug 1, 2016