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• NTP- polymer hybrid composites have been synthesized in wide composition range. • Composites exhibit high ionic conductivity at room temperature. • Structure has been characterized using XANES. • Mechanism for ionic transport has been proposed. Present investigation focuses on conductivity-structure correlation in NaTi 2 (PO 4) 3 (NTP) embedded novel hybrid solid polymer composites prepared in a wide range of composition 10NaI-90(PEO 1-x NTP x) (wt%), for 0 ≤ x ≤ 0.7. A maximum ionic conductivity of ˜ 4 × 10-5 Ω-1 cm-1 has been achieved with x = 0.7 at 40 °C that is higher than that of the host PEO-NaI (⁓ 5 × 10-7 Ω-1 cm-1) system by at least two orders of magnitude. Elemental mapping during field emission scanning electron microscopy suggests homogeneous distribution of NTP in the compositions. Trends of K-edge energies of oxygen in the X-Ray absorption near edge structure spectra have been found to be useful in proposing a tentative mechanism for ionic transport. Structural and impedance spectroscopy investigations suggest that for low NTP content, salt ions prefer to move through polymer. However, for higher content, surface states of NASICON at polymer-NTP interface facilitate the ionic conduction. [ABSTRACT FROM AUTHOR]

We report the results of the studies on crystal structure, electronic structure and dielectric properties of Er 1-x La x FeO 3 (ELFO) (x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0) orthoferrites synthesized by co-precipitation method. Rietveld refinement of the XRD data confirms the orthorhombic crystal structure for all the samples. The study of Fe L 3,2 -edge X-ray Absorption spectroscopy shows the presence of Fe-ions in 3 + valence state in all the samples. Investigations on the dielectric behavior of ELFO samples over the wide frequency range of 20 Hz to 5 MHz show the increment in the dielectric constant with La-doping. ErFeO 3 has the lowest value of dielectric constant whereas LaFeO 3 has the highest value of dielectric constant among all the samples. Effect of grain and grain boundary contribution on the dielectric behavior is studied using complex dielectric permittivity. The observed colossal dielectric behavior in LaFeO 3 is attributed to the combined contribution from the intrinsic dielectric constant of the material and that due to the modification in the microstructure. • Synthesis of La-doped ErFeO 3 orthoferrites using co-precipitation method. • Effect of La-doping on the room temperature dielectric behavior. • Role of microstructure on the dielectric properties of orthoferrites. [ABSTRACT FROM AUTHOR]

Highlights • Under-doped to over-doped boron doped diamond films. • T c suppression in boron doped diamond films. • Impurity band structure across the metal-to-insulator (MIT) transition. • Core excitons in superconducting boron doped diamond films. Abstract Our work investigates the impurity band and the core excitonic level evolution of a series of systematically boron doped diamond (BDD) films using Raman and X-ray absorption (XAS) spectroscopies. The resistivity versus temperature data shows that T c of the BDD films achieves a peak at a maximum gaseous phase boron to carbon ratio, [ B C ] max , beyond which T c drops gradually as a result of excess defect formation, revealing a dome-shaped behaviour. Study of lattice expansion clearly shows the unambiguous presence of substitutional boron atoms beyond [ B C ] max. Direct probe of the impurity band using XAS show a systematic increase in the absorption intensity of the bandgap states which ultimately degrades as the limit of B C > [ B C ] max is exceeded. The binding energy of the BDD 1s core exciton reveal a shallow measured value of 0.11 eV. This is less than earlier found values of 0.19 - 1.2 eV, in various reports for intrinsic diamond. [ABSTRACT FROM AUTHOR]

The present work reports preparation of polycrystalline G d F e 1 − x M n x O 3 (x = 0.0 to 0.5) samples with solid-state reaction method and characterization using x-ray diffraction, 57 Fe Mössbauer spectroscopy, magnetization measurements, leakage current density and soft x-ray absorption spectroscopy measurements. Although F e 3 + and M n 3 + have similar ionic radii, noticeable variations in lattice parameters are seen which are attributed to local distortions introduced by Jahn-Teller active M n 3 + doping. Antiferromagnetic transition temperature corresponding to F e 3 + ordering ( T N , F e ) and G d 3 + ordering ( T N , G d ) is found to decrease with Mn doping, which could be due to weakening of Fe-Fe interaction and Gd-Gd interactions respectively. The Mn substitution at Fe site in G d F e O 3 is found to induce F e 3 + spin reorientation transition ( T S R T ) at a critical concentration and T S R T is found to increase with the Mn doping. Temperature dependent 57 Fe Mössbauer measurements have been carried out to study the local distortions by estimating quadrupole shift, the evolution of magnetism and also the spin reorientation transition in G d F e O 3 with Mn doping. Leakage current density is found to increase with Mn doping in G d F e O 3 , initially very fast and almost saturating for higher concentrations of Mn doping due to the formation of multiple oxidation states of dopant Mn at lower concentrations as evidenced from soft x-ray absorption spectroscopy measurements. [ABSTRACT FROM AUTHOR]

Radio Frequency magnetron sputtering technique has been used to prepare Ni doped ZnO thin films with varying Ni doping concentration of upto 10 at.%. Grazing Incidence X-ray Diffraction results show wurtzite structure of the samples throughout the Ni concentration range while X-ray Near Edge Structure (XANES) and Extended X-ray Absorption Fine Structure results at Zn and Ni K edges show that Ni is substituting Zn in ZnO lattice and no other extra phase is present in the samples. The substitution of Zn by Ni is further confirmed by O K-edge XANES measurements. Photoluminescence measurements on the samples and theoretical simulations of the XANES spectra at Ni and O K-edges have been used to explain the room temperature ferromagnetic character on the basis of the presence of oxygen vacancies in the samples. [ABSTRACT FROM AUTHOR]

Structural, magnetic and electronic properties of partially inverted Cobalt Ferrite with composition Co 1.5 Fe 1.5 O 4 is discussed in the present work. Single phase (SG: Fd3m) sample is synthesized by co-precipitation technique and subsequent air annealing. The values of saturation magnetization obtained from careful analysis of approach to saturation in initial M(H) curves are used to determine spin states of Co ions in tetrahedral (T H ) and octahedral (O H ) sites. Spin states of Co 3+ ions in T H sites, which has not been reported in literature, were found to be in high spin state. Temperature variation of magnetic parameters has been studied. The sample shows magneto-crystalline anisotropy with two clearly distinct pinning centers. Oxygen K-edge and Fe as well as Co L 2,3 -edge X-ray absorption (XAS) spectra have been used as complementary measurements to study crystal field splitting and core hole effects on transition metal (TM) 3d orbitals. The ratio of intensities of t 2g and e g absorption bands in O-K edge XAS spectrum is used to estimate the spin states of Co ions at O H and T H sites. The results are in agreement with those obtained from magnetization data, and favors Co 3+ ions in T H sites in high spin states. Normalized areas of the satellite peaks in TM L 2 , 3 -edge XAS spectra have been used to estimate 3d n+1 L contribution in ground state wave function and the contributions were found to be significant. [ABSTRACT FROM AUTHOR]

Herein, we have investigated the electronic properties of Fe doped Eu 2 O 3 thin film using x-ray absorption spectroscopy (XAS), valence band spectroscopy and resonant photoemission spectroscopy (RPES). The Fe L 3, 2 edge XAS spectra confirms the “3+” ionic state of the Fe in the film. The valence band spectrum of Fe doped film shows an enhancement in the intensity of feature “A” close to Fermi level and origin of another feature “E” at 11.1 eV. The valence band spectroscopy measurements have been performed at the energies in the Eu 4 d → 4 f and Fe 3 p → 3 d photo absorption region that clearly disentangles the features in valence band to be of either Eu and Fe hybridized with O or to be of Eu and O only. [ABSTRACT FROM AUTHOR]

Abstract: X-ray absorption near edge structure (XANES) spectroscopy, X-ray photoelectron spectroscopy (XPS), and Synchrotron X-ray diffraction (SXRD) techniques are used to study as synthesized and isochronally annealed samples of cobalt oxide nanoparticles (NPs) grown using the wet chemical route. Quantitative phase composition determined using Linear Combination Fitting (LCF) on XANES data is found to be in reasonably good agreement with that obtained from Rietveld refinement on SXRD data. XPS data qualitatively indicate that Co3O4 concentration increases with increase in the annealing temperature, in confirmation with SXRD and XANES data. Larger shifts in the satellite peaks from the main peaks compared to these in bulk suggest larger crystal field splitting in nanoparticles as compared to the bulk. [Copyright &y& Elsevier]

The CeO 2-δ and Ce 1-x Nd x O 2-δ (x = 0.02, 0.04 and 0.06) nanoparticles, synthesized by microwave assisted co-precipitation method have been investigated for structural, optical, electronic structure and magnetic properties using X-ray diffraction, transmission electron microscopy, Absorption spectroscopy, surface enhanced Raman spectroscopy, X-ray absorption spectroscopy (XAS), and SQUID magnetometer. TEM and XRD measurements indicate face-centred cubic fluorite structure of CeO 2 with Fm -3 m space group. The Raman spectroscopy indicates that all the Nd3+-doped CeO 2 samples downward shifting of F 2g band with introduction of oxygen vacancies. Further, band gap decrement has been observed with incorporation of Nd3+ ions in CeO 2 lattice. The XAS spectra of Ce M − edge clearly indicate changed valence state of Ce ions from Ce4+ to Ce3+ with Nd3+ doping concentrations. The formation of oxygen vacancies is also confirmed with O K- and Nd M-edges XAS analysis. It is revealed that new complexes Ce3+-V O - Nd3+ and Ce4+- V O –Ce3+ have been introduced to support FM ordering through the development of F+-centres. Therefore, it can be concluded that oxygen vacancies play a prominent role in improving the ferromagnetic and various properties of these nanomaterials, to make them suitable for many applications as UV blocker, Photocatalyst, Spintronics and Optoelectronics applications. • Nd-doped CeO 2 nanoparticles, synthesized using co-precipitation method. • Characterization using XRD, Transmission Electron Microscopy, SQUID-VSM, Raman and X-ray Absorption Spectroscopy. • XRD and Raman analysis confirms formation of face-centred cubic fluorite structure with Fm -3 m space group. • Formation of oxygen vacancies in all samples, which is confirmed with O K-, Ce M − and Nd M-edges XAS analysis. • Formation of Ce3+-V o -Nd3+ and Ce4+-V o -Ce3+ F-centres to give rise to Room Temperature Ferromagnetism in all samples. [ABSTRACT FROM AUTHOR]

The structural, optical and electronic structure properties of all the Zn 1-x Co x O nanoparticles [x = 0.01, 0.03, and 0.05], synthesized using co-precipitation method have been studied using X-ray diffraction (XRD), Surface Enhanced Raman Spectroscopy (SERS), UV–Vis–NIR spectroscopy and X-ray Absorption Spectroscopy measurements. The XRD and SERS analysis have confirmed the formation of hexagonal wurtzite structure (space group C4 6v). UV–Vis–NIR spectra indicate the blue shifting of the absorbance edge and the band gap is found to decrease with doping. The electronic structure of undoped and Co-doped ZnO nanoparticles have been investigated using site selective and element sensitive X-ray absorption spectroscopy. From the XAS spectra at Zn L 3,2 , Co L 3,2 and O K-edges we have found that Zn ions are in +2 valence state in undoped and Co-doped ZnO nanoparticles. From the XAS analysis it can be seen that proper incorporation of Co-ion in the host lattice take place in t 2g e g state Co+2 (d7) under tetrahedral symmetry and maintain the crystal symmetry with lattice distortion. The Co-ion doping in the ZnO nano-matrix leads to creation of various defects & oxygen vacancies, which results in the blue shift in band-gap energy makes them useful for various applications e.g. photocatalytic water splitting, hydrogen generation, spintronics and optoelectronics. • Co-doped ZnO nanomaterials, synthesized using co-precipitation method. • Material Characterization using X-ray diffraction, Transmission electron microscopy, Raman and X-ray Absorption spectroscopy. • XRD and Raman analysis confirms formation of hexagonal wurtzite structure (space group C4 6v) with Co+2 ions in ZnO lattice. • Absorption spectra indicate the blue shifting of the edge with doping. • The Zn and Co valence state is +2 confirmed by XAS at Zn L 3,2 , Co L 3,2 and O K edges with introduction of oxygen vacancies. [ABSTRACT FROM AUTHOR]

• Fabrication of Ca-doped BiFeO3 films using Pulsed Laser Deposition. • Improvement in the ferroelectric behavior of BiFeO3 films with Ca-doping. • Role of strong hybridization between Fe3d–O2p for the improvement in ferroelectric behavior. Effect of Ca – doping on electronic structure and ferroelectric properties have been studied on PLD grown Bi 1-x Ca x FeO 3 /SNTO (x = 0.05, 0.10, 0.20) films. The structural study confirms single crystalline (100) oriented epitaxial growth of the films. The observed improvement in the ferroelectric behavior with an increase in Ca – doping has been attributed to the strong hybridization between Fe3d–O2p and localization of Fe3de g and Bi6s-O2p orbitals understood using X-ray Absorption Spectroscopy measurements. Ferroelectric measurements performed on BCFO films show the finite value of intrinsic ferroelectric polarization, though the contributions from the non – ferroelectric components lead to unsaturated and leaky loop. The sub-bandgap transition observed in the absorption spectra indicates the presence of oxygen vacancy states which is one of the reasons for observed leakage in polarization measurements. [ABSTRACT FROM AUTHOR]