Twinning processes in Cu–Al–Ni martensite single crystals investigated by neutron single crystal diffraction method

2008 ◽  
Vol 481-482 ◽  
pp. 513-517 ◽  
Author(s):  
P. Molnár ◽  
P. Šittner ◽  
V. Novák ◽  
P. Lukáš
2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Durga Sankar Vavilapalli ◽  
Ambrose A. Melvin ◽  
F. Bellarmine ◽  
Ramanjaneyulu Mannam ◽  
Srihari Velaga ◽  
...  

AbstractIdeal sillenite type Bi12FeO20 (BFO) micron sized single crystals have been successfully grown via inexpensive hydrothermal method. The refined single crystal X-ray diffraction data reveals cubic Bi12FeO20 structure with single crystal parameters. Occurrence of rare Fe4+ state is identified via X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS). The lattice parameter (a) and corresponding molar volume (Vm) of Bi12FeO20 have been measured in the temperature range of 30–700 °C by the X-ray diffraction method. The thermal expansion coefficient (α) 3.93 × 10–5 K−1 was calculated from the measured values of the parameters. Electronic structure and density of states are investigated by first principle calculations. Photoelectrochemical measurements on single crystals with bandgap of 2 eV reveal significant photo response. The photoactivity of as grown crystals were further investigated by degrading organic effluents such as Methylene blue (MB) and Congo red (CR) under natural sunlight. BFO showed photodegradation efficiency about 74.23% and 32.10% for degrading MB and CR respectively. Interesting morphology and microstructure of pointed spearhead like BFO crystals provide a new insight in designing and synthesizing multifunctional single crystals.


2013 ◽  
Vol 46 (2) ◽  
pp. 387-390 ◽  
Author(s):  
Hui Li ◽  
Xiaodong Li ◽  
Meng He ◽  
Yanchun Li ◽  
Jing Liu ◽  
...  

High-pressure single-crystal diffraction experiments often suffer from the crushing of single crystals due to the application of high pressure. Consequently, only diffraction data resulting from several particles in random orientations is available, which cannot be routinely indexed by commonly used methods designed for single-crystal data. A protocol is proposed to index such diffraction data. The techniques of powder pattern indexing are first used to propose the possible lattice parameters, and then a genetic algorithm is applied to determine the orientation of the reciprocal lattice for each of the particles. This protocol has been verified experimentally.


2014 ◽  
Vol 70 (a1) ◽  
pp. C402-C402
Author(s):  
Nicola Casati ◽  
Annette Kleppe ◽  
Fabrizio Nestola ◽  
Heribert Wilhelm

The Extreme Condition beamline (I15) at the Diamond Light Source is a dedicated beamline for powder as well as single crystal diffraction on samples at extreme conditions in pressure or temperature. Single crystal data on either pressurized samples in a diamond anvil cell (DAC) or at ambient conditions are routinely done on a diffractometer scanning φ and ω using X-rays with energies in the range from 20 keV to 80 keV. Depending on the sample beam sizes varying from 20 μm to several 100 μm can be used. Data are recorded with an Atlas CCD (Agilent Technologies) and then treated with the Crysalis software package. In this contribution we highlight the very high accuracy of single-crystals data obtainable at I15 on two examples of single crystals in a DAC (E = 40 keV) and a sample at ambient conditions (E = 60 keV). A single crystal of the binary transition metal compound FeGe (B20 structure, space group P213, Z=4) was studied up to 11 GPa to determine the evolution of the inter-atomic distances (both atoms occupy the 4a Wyckoff positions). More than 200 unique data could be used to refine 7 parameters with an average R1 on all data of ~7%. Very high quality data have also been obtained for single crystals from the field of chemical crystallography, for which not only connectivity but also small bonding features can be detected. For example in l,6;8,13 biscarbonyl[14]annulene the progressive loss of aromatic character could be monitored and, in a special setup, the data allowed for the refinement of an unconstrained multipolar model. The use of 60 keV photons was crucial for an experiment on natural diamonds containing a variety of inclusions. At these energies the absorption of the diamond can be neglected. The aim of the study was to obtain information on possible recurrent crystallographic relationships between the inclusions and the diamond host on a significant number of extremely rare natural diamonds containing minerals.


2003 ◽  
Vol 58 (1) ◽  
pp. 201-204 ◽  
Author(s):  
Olaf Reckeweg ◽  
Francis J. DiSalvo

Abstract Red transparent single crystals of Ba9[NbN4]2O[CN2] were synthesised by the reaction of BaO coated Ba metal, C and Nb powder in arc-welded Nb ampoules at 1300 K. The title compound was characterised by X-ray single crystal diffraction (P1̅ , a = 799.05(2), b = 962.61(2) and c = 1264.38(4) pm; α = 75.859(1), β = 85.745(1) and γ = 87.8621(8)°; Z = 2) and Raman spectroscopy (νsym = 1234 and δ = 632/658/668 cm−1). It now seems likely that a nitride-azide compound we previously reported, Ba9[NbN4]2N[N3], does not exist, but is in fact the title compound.


1978 ◽  
Vol 42 (321) ◽  
pp. 41-44
Author(s):  
Hartmut Schneider

SummaryThe deformation of biotite single crystals submitted to experimental shock-pressures of about 200 and 400 kb with direction of the shock wave parallel to [001] was investigated by X-ray precession and Weissenberg techniques. The X-ray analysis reveals a ‘fracturing’ of the biotite crystals upon pressure release into relatively large lattice blocks (> 1000 Å), which increases with the degree of shock compression. Deformation is inferred to take place by gliding and/or microfracturing processes parallel to the (010) and (110) lattice planes. Chains of tetrahedra running parallel to [100] and [110] probably exert a controlling influence on shock deformation mechanisms.


CrystEngComm ◽  
2021 ◽  
Author(s):  
O.D. Chimitova ◽  
B.G. Bazarov ◽  
Jibzema G. Bazarova ◽  
Victor V. Atuchin ◽  
Raheleh Azmi ◽  
...  

Single crystals of RbFe5(MoO4)7 were successfully grown by the flux method, and its crystal structure was determined using the X-ray single-crystal diffraction technique. The XRD analysis showed that the compound...


2019 ◽  
Vol 234 (4) ◽  
pp. 277-280 ◽  
Author(s):  
Laura Henry ◽  
Volodymyr Svitlyk ◽  
Gaston Garbarino ◽  
David Sifre ◽  
Mohamed Mezouar

Abstract Single crystals of solid chlorine (Cl2) were synthesized at room temperature and high pressure (HP, P=1.45 GPa) in a diamond anvil cell (DAC). At these conditions Cl2 adapts the same structure as its corresponding low-temperature (LT) ambient pressure modification (T<172 K), as concluded from HP single crystal diffraction experiments. Namely, it crystallizes in an orthorhombic symmetry (Cmce spacegroup) with Cl2 molecules forming monolayers parallel to the bc plane and this structure is preserved up to at least 64 GPa. The pressure of 1.45 GPa is to be considered as a solidification point of liquid Cl2 at room temperature.


2003 ◽  
Vol 59 (4) ◽  
pp. 492-497 ◽  
Author(s):  
V. A. Tafeenko ◽  
V. V. Chernyshev ◽  
A. V. Yatsenko ◽  
V. A. Makarov ◽  
E. J. Sonneveld ◽  
...  

The title compound was synthesized and isolated in two crystal modifications. The structure of the orthorhombic modification was determined by the X-ray powder diffraction method and the structure of the monoclinic modification was determined using the X-ray single-crystal diffraction technique. The molecules in both polymorphs are E,E isomers. Intermolecular H3C...NO2 contacts and their role in the formation of the polymorphic modifications are analyzed.


Sign in / Sign up

Export Citation Format

Share Document