Single Crystal Research Papers - Academia.edu (original) (raw)

We report on structural, magnetic, electrical, and thermodynamic properties of Gd-doped LaMnO3 single crystals for Gd doping levels 0 <= x <= 1. At room temperature, for all doping levels the orthorhombic O' phase is indicative for a strong Jahn-Teller distortion. All compositions are insulating. The magnetism of La$_{1-x}$Gd$_x$MnO$_3$ is dominated by the relatively strong Mn-Mn exchange. The weakening of the antiferromagnetic interactions due to the significant decrease f the Mn-O-Mn bond angles leads to the continuous suppression of the magnetic phase-transition temperatures into the antiferromagnetic low-temperature phase for increasing Gd doping. The magnetization can only be explained assuming canting of the manganese spins. The magnetic moments of Gd are weakly antiferromagnetically coupled within the sublattice and are antiferromagnetically coupled to the Mn moments. For intermediate concentrations compensation points are found, below which the spontaneous magnetization becomes negative. In pure GdMnO3 the Mn spins undergo a transition into a complex, probably incommensurate magnetic structure at 41.5 K, followed by a further ordering transition at 16-20 K revealing weak ferromagnetism due to canting and finally by the onset of magnetic order in the Gd sublattice at 6.5 K. At the lowest temperatures and low external fields both magnetic sublattices reveal a canted structure with antiparallel ferromagnetic components.

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- Physical sciences, CHEMICAL SCIENCES, Room Temperature, Single Crystal
- by masanori satoh
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- Modern physics, Physical sciences, Single Crystal, Tungsten

We have developed a modified physical vapor transport (M-PVT) growth technique for the preparation of SiC single crystals which makes use of an additional gas pipe in order to control the gas phase composition of the conventional physical... more

- by Francis Baillet
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- Materials Science, Crystal Growth, Phosphorus, Numerical Simulation
- by Gajanan Muley
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- Crystal Growth, Nonlinear Optics, FTIR spectroscopy, Second Harmonic Generation

The preparation of three new examples of water insoluble host/guest assemblies of the general composition:[(R4N)(Me3Sn) 2M (CN) 6· zH2O](R= n-propyl or n-pentyl, M= Fe or Co, 0≤ z≤ 2) from likewise polymeric super-Prussian-blue... more

- by Solomon Samba
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- Chemistry, Inorganic Chemistry, Solid State Chemistry, Solid State NMR
- by Roberta Toro and +2
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- Materials Engineering, Condensed Matter Physics, Surface Coatings, Copper

ZnMn2O4 crystallizes at high temperatures as a cubic spinel. At lower temperatures, it undergoes a Jahn Teller distortion which lowers its symmetry to tetragonal. At lower temperatures (TN& tilde;60 K), the system orders magnetically. Fits to the order parameter, line shape of powder diffraction peaks, and the direct observation of rods of scattering in single crystal diffraction experiments show the system to be two dimensional. This is likely due to the interplay between orbital ordering and frustration. In this talk I discuss the magnetic structure and spin waves of this system. I will also discuss an interesting crossover in the dimensionality of the magnetism in this compound.

- by Jeffrey Lynn and +2
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- Powder Diffraction, High Temperature, Single Crystal, Order Parameter
- by Alejandro Granados
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- Chemistry, Inorganic Chemistry, Crystallography, Crystal structure
- by Armel Le Bail
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- Condensed Matter Physics, Chemistry, Analytical Chemistry, Quantum Mechanics

Bisthiourea Zinc Acetate (BTZA) a semi organic material has been synthesized by slow evaporation method using water as a solvent. The solubility studies have been carried out in aqueous solution in the temperature range 25 ˚C – 45 ˚C. Crystals have been grown from low temperature solution method by slow evaporation of saturated aqueous solution at room temperature. Single Crystal X-ray diffraction study has been carried out to determine the lattice parameter of the grown crystal. The spectral bands have been compared with similar thiourea complexes using FTIR spectrum in the range 400 – 4000 cm-1. Optical transmittance and absorption percentage of the grown crystal have been measured from UV-Vis studies. The thermal behavior has been investigated by thermogravimetric (TGA) and Differential Thermogram analyses (DTA). The mechanical strength and work hardening coefficient of the grown crystal have been analyzed by Vicker’s microhardness method. Keywords: Growth from solutions; X-ray d...

- by Ruby Nirmala
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- Computer Science, Chemistry, Nonlinear Optics, Zinc

Photoemission spectra taken at room temperature with high energy and angle resolution on Bi2Sr2CaCu2O8 single crystals reveal a band near EF with weak dispersion along lambdaX. It crosses EF at about 1/2 lambdaX and the occupied part becomes visible up to the Brillouin zone boundary in angle-resolved inverse photoemission spectra. Starting for T&gt;Tc with a clear Fermi edge, for T&lt;Tc

- by Recardo Manzke and +1
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- Materials Engineering, Physics, Condensed Matter Physics, Electronic Structure
- by Timothy Stemmler
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- Inorganic Chemistry, Photosynthesis, Plant Biology, Quantum Theory

It is shown that it is possible to use synchrotron X-radiation to measure fast fluorescent emission in compounds not readily available in single-crystal form. Of 85 compounds tested, about half were found to have fluorescence below the limit of the technique used, which was about 0.05% of Bi4Ge3O12 (BGO). Others had emissions in the 0.1 to 1% range, and a

- by Adnan Abu-Surrah
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- Inorganic Chemistry, Cell line, Transition metal chemistry, Single Crystal
- by Emmanuel Le Clézio
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- Engineering, Physical sciences, Domain wall, Dielectric Constant
- by Hiranmay Saha
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- Crystallography, Solar Cells, Mass production, Grain size
- by D. Pelloquin
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- Materials Engineering, Condensed Matter Physics, Copper, Superconductors
- by Sigmund Andersen
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- Engineering, Electron Microscopy, Epitaxial Growth, Applied Physics
- by Alexei Gruverman
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- Atomic Force Microscopy, Multidisciplinary, Thin Film, Electron Transport
- by A. Zavalin and +1
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- Electronic Materials, Single Crystal, Electrical And Electronic Engineering
- by Ming-Yang He
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- Inorganic Chemistry, Self Assembly, Solvent Effect, X ray diffraction
- by Ivan Rychetský
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- Condensed Matter Physics, Raman Spectroscopy, Thin Film, Far Infrared

For Abstract see ChemInform Abstract in Full Text.

- by Jekabs Grins and +1
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- Engineering, Materials Chemistry, Nuclear Magnetic Resonance, X Rays

Single crystal X-ray diffraction was applied in order to investigate defect-induced microstructures in radiation damaged zircon. The formation of domains with different degrees of order was observed and in particular, it was possible to distinguish two types of defects: isolated lattice defects and dislocations. These lattice deformations have a great influence on the structural and physical properties of the materials.

- by Isabella Memmi
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- Engineering, Materials Science, RADIATION DAMAGE, Dislocations
- by Barbara Shollock
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- Materials Engineering, Mechanical Engineering, Nickel, Grain Boundary
- by Shalini Menezes and +1
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- Materials Engineering, Arsenic, Solar Cell, Phosphorus

The deformation behavior of aluminum single crystals subjected to compression along the [100] and [110] directions is numerically examined in terms of crystal plasticity. A constitutive model taking into account slip geometry in face-centered cubic crystals is developed using experimental
data for the single-crystal samples with lateral sides coplanar to certain crystal planes. Two sets of calculations are performed using ABAQUS/Explicit to examine the features of plastic strain evolution in perfectly plastic and strain-hardened crystals. Special attention is given to the discussion of mechanical aspects of crystal fragmentation. Several distinct deformation stages are revealed in the calculations. In the first stage, narrow solitary fronts of plastic deformation are alternately formed near the top or bottom surfaces and then propagate towards opposite ends to save the symmetry of the crystal shape. The strain rate within the fronts is an order of magnitude higher than the average strain rate. The first stage lasts longer in the strain-hardened crystals, eventually giving way to an intermediate stage of multiple slips in different crystal parts. Finally, the crystal shape becomes asymmetrical, but no pronounced macroscopic strain localization has been revealed at any
deformation stage. The second stage in perfectly plastic crystals relates to abrupt strain localization within a through-thickness band-shaped region, accompanied by macroscale crystal fragmentation. Stress analysis has shown that pure compression took place only in the first deformation stage. Once the crystal shape has lost its symmetry, the compressive stress in some regions progressively decreases to zero and eventually turns tensile.

- by Varvara Romanova and +2
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- Aluminium Alloys, Crystal Plasticity, Single Crystal, Strain localization
- by Ivan Ogorodnyk
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- Materials Science, Inorganic Chemistry, FTIR spectroscopy, Solid State Chemistry
- by Elif Genceli Guner
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- Materials Engineering, Inorganic Chemistry, Crystal Growth, Raman Spectroscopy
- by Werner van Zyl
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- NMR Spectroscopy, Crystal structure, Metal Complexes, Single Crystal
- by Princia Salvatore
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- Electrochemistry, Atomic Force Microscopy, Single molecule, Metal Nanoparticles
- by František Šutara
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- Engineering, Technology, Epitaxial Growth, PHOTOELECTRON SPECTROSCOPY
- by Rafael Silva
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- Technology, Kinetics, Titanium, Crystallization
- by Siddharth S Saxena and +1
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- High Pressure, Physical sciences, CHEMICAL SCIENCES, Single Crystal
- by Julien Didierjean and +1
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- Crystal Growth, Single Crystal Growth, Single Crystal, Continuous Wave

... Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, and Dipartimento di Chimica Organica “A Mangini”, Universita di Bologna, Via S. Donato 15, I-40127, Bologna, Italy. J. Am. Chem. Soc. ...

- by Silvia Pieraccini
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- Circular Dichroism, Potassium, The, Hydrogen Bond

Two copper (II) complexes of 2, 3-pyrazinedicarboxylate (pzdca) with N, N′-dimethylethylenediamine (dmen),[Cu2 (pzdca) 2 (H2O) 2 (dmen) 2]· 6H2O (1) and 1, 10-phenanthroline (phen),[Cu (pzdca)(phen) 2]· 5.5 H2O (2), have been prepared and... more

- by murat taş
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- Chemistry, Inorganic Chemistry, Coordination Chemistry, Copper

Pegmatite deposits commonly occur in the 1500 km long, N-S-trending, tungstentin-bearing granitoid belt in Myanmar. Pegmatites are emplaced as veins and dikes that cut granitoid, migmatite, granitoid gneiss, gneiss, and schist. The pegmatite veins and dikes are mostly 2 to 5 meters wide and 30 to 150 meters long, and some are traceable over a distance of 300 meters.The pegmatites

- by Zin Zircon
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- Geology, Geochemistry, Geophysics, Potassium
- by klaus bente
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- Materials Engineering, Condensed Matter Physics, X Rays, Superconductors
- by Peter Rogl
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- Materials Engineering, Powder Diffraction, Intermetallics, Crystal chemistry
- by Anthony Kotlar
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- Inorganic Chemistry, Crystal structure, Magnesium, Single Crystal
- by Joshua Yu
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- Inorganic Chemistry, Cyclic Voltammetry, Crystal structure, X ray diffraction
- by Ikumu Watanabe
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- Materials Engineering, Mechanical Engineering, Civil Engineering, Plasticity
- by Neha Singh
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- Scanning Electron Microscopy, Thin Films, Zinc Oxide, Thin Film