- Neutron diffraction studies of the compounds MnN and FeN
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The compounds MnN and FeN were prepared as single phase sample by DC reactive sputtering. The crystal structure of MnN is tetragonally distorted NaCl type and that of FeN is ZnS type. Temperature dependence of the neutron diffraction pattern on MnN was in
- Suzuki, Kenji,Yamaguchi, Yasuo,Kaneko, Takejiro,Yoshida, Hajime,Obi, Yoshihisa,Fujimori, Hiroyasu,Morita, Hiroaki
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- XPS, AES, and EELS characterization of nitrogen-containing thin films
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Pulsed laser deposition (PLD) appears to be a very efficient tool for material synthesis. Interstitial compounds like hydrides, carbides, and nitrides are usually produced by reactive variations of PLD. In this study, a methodical routine based in PLD is used to synthesize nitrogen-containing films by ablating pure-element targets in molecular nitrogen environments. The resulting films are analyzed in situ by X-ray photoelectron (XP), Auger-electron (AE), and electron energy loss (EEL) spectroscopies. Our methodology confirms the existence of remarkable regularities in the spectroscopic characteristics of those films. For example, the N-KVV Auger transition for nitrogen contained in d-metals is split in three main energy bands and several additional subbands. For the main bands, their relative intensities correlate with electronic populations in d-orbitals, while the subbands can be associated to energy losses of the main bands. We propose that the main bands reflect the bonding, non-bonding and anti-bonding interactions between nitrogen and partner element. By means of XPS measurements, core-level energy shifts are detected and they are relative to the amount of nitrogen incorporated in the films. In the EELS section, an association between the loss-structure of pure-elements and nitrides is presented. With few exceptions, the bulk plasmon energy in nitrides is larger than in pure-elements, indicative of an increase in the electronic density of nitrides. The peak structure of the N-KVV transition, the XP binding energies and the loss spectra are presented; this data can be of valuable assistance for the analysis of nitride formation.
- Soto,De La Cruz,Farías
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- Spectroscopic and fluorescence studies on Mn(II), Co(II), Ni(II) and Cu(II) complexes with NO donor fluorescence dyes
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The reactions of the two common dyes [2TMPACT and 4PENI] with Mn(II), Co(II), Ni(II) and Cu(II) ions were done. All the isolated complexes have been characterized by physicochemical and spectroscopic techniques. The IR data reflect the bidentate mode of 2TMPACT towards the mononuclear complex [Mn(II)] even its tetradentate in binuclear complexes [Co(II) and Cu(II)]. However, the bidentate mode is the only behavior of 4PENI ligand towards each metal ion in its mononuclear complexes. The UV-vis spectral analysis beside the magnetic moment measurements are proposed different geometries concerning each metal ions with the two ligands under investigation, as the Mn(II)-2TMPACT complex is an octahedral but Mn(II)-4PENI is a tetrahedral geometry. All the synthesized compounds are thermogravimetrically investigated. The proposed thermal decomposition was discussed for each compound with each step as well as, the kinetic parameters were calculated for all preferrible decomposition steps. The mass spectroscopy tool was used to emphasis on the suitable molecular formula proposed and the fragmentation patterns were displayed. The fluorescence properties of the synthesized ligands and their complexes were studied in DMSO at room temperature.
- Refat, Moamen S.,El-Metwaly, Nashwa M.
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- Lithium imide synergy with 3d transition-metal nitrides leading to unprecedented catalytic activities for ammonia decomposition
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Alkali metals have been widely employed as catalyst promoters; however, the promoting mechanism remains essentially unclear. Li, when in the imide form, is shown to synergize with 3d transition metals or their nitrides TM(N) spreading from Ti to Cu, leadi
- Guo, Jianping,Wang, Peikun,Wu, Guotao,Hu, Daqiang,Xiong, Zhitao,Wang, Junhu,Yu, Pei,Chang, Fei,Chen, Ping,Wu, Anan,Chen, Zheng
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- Crystal structure and magnetic properties of the compound MnN
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The compound MnN was prepared as a single phase by DC reactive sputtering. Its crystal structure is determined to be face-centered tetragonal one with the NaCl type by X-ray diffraction measurements. The compound MnN is stable up to 753 K and decomposes to tetragonal Mn3N2 at 758 K. This compound exhibits a antiferromagnetism.
- Suzuki,Kaneko,Yoshida,Obi,Fujimori,Morita
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- Anomalous thermal expansion of MnN
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The MnN compound is prepared as a single phase by d.c. reactive sputtering. The crystal structure of MnN is tetragonally distorted NaCl type (fct) one. The temperature variation of lattice constants for MnN is measured by X-ray diffraction experiments in the temperature range from 289 to 803 K. It is found that the MnN compound shows anomalous thermal expansion and the crystal structure of MnN has changed from fct structure to fcc one at about 650 K. On the other hand, we found formerly that MnN was an antiferromagnetic compound with a Néel temperature of 650 K. The tetragonal distortion below about 650 K is well explained by the strain dependence of the exchange interaction on the basis of molecular field theory.
- Suzuki,Suzuki,Fujinaga,Kaneko,Yoshida,Obi,Tomiyoshi
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- Solvothermal metal azide decomposition routes to nanocrystalline metastable nickel, iron, and manganese nitrides
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This paper describes the use of solvothermally moderated metal azide decomposition as a route to nanocrystalline mid to late transition metal nitrides. This method utilizes exothermic solid-state metathesis reaction precursor pairs, namely, metal halides
- Choi, Jonglak,Gillan, Edward G.
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- Spectral, thermal and biological studies of Mn(II) and Cu(II) complexes with two thiosemicarbazide derivatives
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Two derivatives of thiosemicarbazide were prepared. Their complexes were prepared using Mn(II) and Cu(II) salts. All the isolated complexes are characterized using the following spectra: IR, UV-Vis, Mass, 1H NMR and X-ray diffraction. Magnetic measurements and thermal analysis are the other additive tools for complete investigation. Mononuclear and binuclear complexes are proposed based on elemental analysis mainly. The IR spectra offer the mode of coordination of each ligand with each metal ion. The electronic spectra and magnetic measurements are proposing the structural geometry of the investigated complexes. The octahedral geometry proposed for Mn(II) complexes but the square-planar for Cu(II) complexes. The 1H NMR spectra were done for all organic compounds used in this study and displaying the most suitable tautomer of them. X-ray diffraction of H2L1 and its complexes show their amorphous nature but H2L2 ligand and its complexes show their nanocrystalline nature. The TG analysis was used to prove the presence of solvent molecules attached with the complexes as covalently or physically. Finally, the biological investigation was carried out for H2L2 ligand and its complexes and displaying the inhibition activity of Cu(II) complex than the Mn(II) one.
- Refat, Moamen S.,El-Metwaly, Nashwa M.
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p. 336 - 346
(2012/05/07)
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