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Structural properties of hypothetical CeBa2Cu3O7 compound from LSDA+DMFT calculations

1 Introduction (Rare-earth)Ba 2 Cu 3 O 7 (R123) was the first series of high-T C superconducting materials for which it was found out that a diamagnetic yttrium ion Y could be replaced by a magnetic rare-earth element without influencing the superconductivity [ 1 ]. It was also noted that there were three exceptions, namely, Ce, Pr and Tb. Interestingly, ab initio electronic structure calculations showed that electronic bands of PrBa 2 Cu 3 O 7 [ 2 – 5 ] or the hypothetical stoichiometric CeBa 2 Cu 3 O 7 [ 6 ] and TbBa 2 Cu 3 O 7 [ 7 ] systems have

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Mössbauer study of a tetrakis (pentafluorophenyl) porphyrin iron (III) chloride in comparison with the fluorine unsubstituted analogue

Abstract

Mössbauer investigations, in association with density functional theory (DFT) calculations, have been conducted for the molecular and electronic structures of iron (III) [tetrakis (pentafluorophenyl)] porphyrin chloride [(F20TPP)Fe:Cl], as a Fe(III)-tetraphenylporphyrin complex containing chloride axial ligand and substituted hydrogen atoms by fluorine ones in the four phenyl rings, in comparison with its fluorine unsubstituted analogue [(TPP)Fe:Cl]. It was found that the parameters of Mössbauer spectra of both complexes are close to one another, and correspond to the high-spin state of Fe(III) ions, but they show the different temperature dependence and the quadrupole doublets in Mössbauer spectra show different asymmetry at low temperatures. Results of DFT calculations are analyzed in the light of catalytic activity of the halogenated complex.

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Electronic structures of Hg-doped anatase TiO2 with different O vacancy concentrations

Abstract

The electronic structures of Hg-doped anatase TiO2 with different O vacancy concentrations were calculated using the first-principles based on the density functional theory. The calculated results show that the forbidden band widths of Hgdoped anatase TiO2 widened along with the increase of O vacancy concentration, which is responsible for the blue shift in the absorption edges. It can be deduced from the present study that the Hg-doped TiO2 samples prepared in the experimental research contain a certain quantity of O vacancies.

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Electronic structure and possible martensitic transformation in Ni2FeIn alloy

Abstract

The electronic structure and magnetic properties of Heusler alloys (Ni2FeIn) have been studied by first principle calculations. The possible tetragonal martensitic transformation has been predicted and the structure optimization was made on cubic austenitic Ni2FeIn in Cu2MnAl type. The equilibrium lattice constant of austenitic Ni2FeIn is 6.03 Å. In tetragonal phase, the global energy minimum occurs at c/a = 1.29. The corresponding equilibrium lattice constants for martensite Ni2FeIn are a = b = 5.5393 Å and c = 7.1457 Å, respectively. In the austenitic phase, E F is located at the peak in the minority DOS for c/a = 0.96 to 1.20, but in the martensitic phase, E F moves to the bottom of the valley in the minority DOS, reducing the value of N(E F) effectively. Both austenitic and martensitic phases are ferromagnetic and the Ni and Fe partial moments contribute mainly to the total moments. Therefore, the martensitic transformation behavior in Ni2FeIn is predicted.

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Carbon nanotubes functionalized by salts containing stereogenic heteroatoms as electrodes in their battery cells

36, 127–133. DOI: 10.1016/0013-4686(91)85189-E. 13. Vidya, R., Ravindran, P., Kjekshus, A. & Fjellvåg, H. (2006). Crystal and electronic structures of Cr 3 O 8 and LiCr 3 O 8 : Probable cathode materials in Li batteries. Phys. Rev. B . 73, 235113-1-235113-13. DOI: 10.1103/PhysRevB.73.235113. 14. Naoki, K. & Feng, W. (2010). A Comprehensive Review on Separation Methods and Techniques for Single-Walled Carbon Nanotubes. Materials 3(7), 3818–3844. DOI: 10.3390/ma3073818. 15. Mukherjee, A., Combs, R., Chattopadhyay, J. & Abmayr, D.W. (2008

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Electronic and optical properties of Mn–S co-doped anatase TiO2 from first-principles calculations

. [ 13 , 18 ] successfully synthesized S-doped TiO 2 (S/TiO 2 ) by oxidation annealing of TiS 2 . They found that the S atoms replaced O atoms and the S/TiO 2 showed optical redshift. Cui et al. [ 19 ] calculated the electronic structures and optical absorption spectra of S/TiO 2 by means of first-principles calculations. The results indicated that the isolated S 3p states that appeared at the upper edge of the valence band caused the narrowing of the band gap of S/TiO 2 ; Zhang et al. [ 20 ] prepared Mndoped TiO 2 (Mn/TiO 2 ) films by sol-gel method. They found

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Formation of Fe and Ni substituted LiMn2–XMXO4 nanopowders and their crystal and electronic structure and magnetic properties

Abstract

The Pechini sol-gel method was applied to obtain LiMn2–xTxO4 (T = Ni, Fe; x = 0.1 to 0.5) nanopowders. Crystal and electronic structures, chemical composition and magnetic properties of the materials were characterized by X-ray diffraction, XPS, SEM/EDX microscopy, prompt gamma-ray activation analysis (PGAA), Mössbauer spectroscopy and magnetic susceptibility, respectively. XRD measurements showed that the LiMn2–xNixO4 were single phase for x = 0.1 and 0.2. Three samples with higher Ni content contained some addition of a second phase. Analysis of the oxidation state of the dopants by XPS revealed ionic Ni2+ and Fe3+. Mössbauer spectroscopy also confirmed 3+ oxidation state of iron and its location in octahedral sites, which excluded the inverse spinel configuration. XPS examinations showed that Mn3+ ions dominated in the iron substituted series whereas the Mn4+ was dominant in the nickel series.

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Stability and the Electronic Structure of XB2 (X = Pt, Ir, Pd, Rh, Os) Diborides

. Physical Review Letters, 77, 3865. 18. Monkhorst, H.J., & Pack, J.D. (1976). Special points for Brillouin-zone integrations. Phys. Rev. B, 13, 5188 – 5192. 19. Birch, F. (1947). Finite Elastic Strain of Cubic Crystal. Phys. Rev., 71, 809-824. 20. Staple, C., Mannstadt, W., Asahi, R., & Freeman, A.J. (2001). Electronic structure and physical properties of early transition metal mononitrides: Density-functional theory LDA, GGA, and screened-exchange LDA FLAPW calculations. Phys. Rev. B, 63(15), 155106(1-11). 21. James, A.M. & Lord, M.P. (1992

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Electronic Infrastructure Aimed At Improving Comunication And Education For Business And Academia

Abstract

This paper will present an educational method that will help link academia and business. This method will help improve the relations between academia and business in the field of building and testing memory systems. We will provide the basic theoretical structure of our method, and will provide our readers with a case study of one particular testing method that can breach the barrier between academia and business. This method will help both parts in improving their production methods and testing techniques. Our method will promote extended communication by using electronic means (e.g. e-mail, electronic reports, etc.), which will help the two parties work together more efficiently. We will provide an electronic infrastructure that will ease the communication between the two parties. We will also provide a study on a particular example that will prove that there are significant improvements regarding communication and learning, while also reducing the time needed for the academia methods to be implemented in business.

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Magnetic properties of manganese doped PrAlO3 monocrystalline fibres

Abstract

Monocrystalline fibres of undoped PrAlO3 and PrAlO3:0.1 Mn, have been grown by the pulling-down method under nitrogen atmosphere. The as-grown crystal doped with Mn had a visible brown core surrounded by a green ring, whereas this effect was weaker for the undoped PrAlO3. A coloration of the brown core was caused by a presence of Pr4+ ions. The presence of the Pr4+ ions was confirmed by XPS and magnetic studies. The XPS chemical analysis showed the increased concentration of oxygen in the crystals with the brown core. The most probable valency of manganese is Mn4+. It is located in Al3+ sites.

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