Crystal defects in flux grown lithium ferrite, LiFe5O8 single crystals

1979 ◽  
Vol 47 (1-3) ◽  
pp. 263-273 ◽  
Author(s):  
E. Beregi ◽  
E. Sterk ◽  
E. Pál ◽  
M. Farkas-Jahnke
Keyword(s):  
Single Crystals ◽  
Crystal Defects ◽  
Lithium Ferrite

Electron microscopy investigations on the mineral lorándite (TlAsS2) from Allchar in Macedonia

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Tobias Necke ◽  
Maximilian Trapp ◽  
Stefan Lauterbach ◽  
Georg Amthauer ◽  
Hans-Joachim Kleebe
Keyword(s):  
Electron Microscopy ◽  
Single Crystals ◽  
Secondary Phase ◽  
Lattice Energy ◽  
Local Deformation ◽  
Crystal Defects ◽  
Coffee Bean ◽  
Electron Dose ◽  
Chemical Difference ◽  
Natural Mineral

Abstract In this paper, we report on electron microscopy studies of single crystals of the natural mineral lorándite, TlAsS2. The main focus of this investigation was to address the question as to whether those lorándite crystals are chemically and structurally homogeneous, in order to be utilized as an effective neutrino detector within the lorándite experiment (LOREX) project. Apart from few secondary minerals, being present only at the surface of the lorándite samples, scanning electron microscopy (SEM) indicated homogeneous crystals. Similarly, transmission electron microscopy (TEM) imaging revealed a homogenous and undisturbed crystal structure, with the only exception of local coffee-bean contrasts; however, rarely observed. These specific contrast variations are known to be a typical strain indicator caused by a local deformation of the crystal lattice. Energy-dispersive X-ray spectroscopy (EDS) in conjunction with electron energy-loss spectroscopy (EELS) did not show any significant chemical difference when analysing regions on or off those coffee-bean features, indicating a chemically homogenous mineral. Since the presence of lattice disturbing secondary phase precipitates could be excluded by imaging and complementary chemical analysis, crystal defects such as dislocations and stacking faults or minor fluid inclusions are discussed as the probable origin of this local elastic strain. The experimental results confirm that the studied lorándite single crystals fulfil all structural and chemical requirements to be employed as the natural mineral that allows to determine solar neutrino fluxes. In addition, critical issues regarding the rather challenging sample preparation of lorándite are reported and a quantification of the maximum tolerable electron dose in the TEM is presented, since lorándite was found to be sensitive with respect to electron beam irradiation. Furthermore, the limits of EDS measurements due to peak overlapping are shown and discussed utilizing the case of Pb in lorándite. In this regard, a comparison with the Tl- and Pb-containing natural mineral hutchinsonite, TlPbAs5S9, is also included.

The growth of large single crystals of lithium ferrite

1967 ◽  
Vol 2 (3) ◽  
pp. 293-294 ◽  
Author(s):  
A. J. Pointon ◽  
J. M. Robertson
Keyword(s):  
Single Crystals ◽  
Lithium Ferrite

Electric Field Induced De-channeling in LiNbO3

1993 ◽  
Vol 316 ◽  
Author(s):  
R. L. Zimmerman ◽  
D. Ila ◽  
N. Kukhtarev ◽  
E. K. Williams
Keyword(s):  
Electric Field ◽  
Single Crystals ◽  
Ion Beam ◽  
Crystal Defects ◽  
Alpha Particles ◽  
Fringe Field ◽  
Beam Direction ◽  
Ion Channeling ◽  
Piezoelectric Strain ◽  
Mev Protons

ABSTRACTAn electric field has been imposed on single crystals of pure and doped LiNbO3 during bombardment with 1.03 MeV protons and 2.1 MeV alpha particles. Simultaneous (p,p), (p,α) and (p,p'γ) channeling between the crystal planes showed that the channeling is less pronounced when an electric field of 106 volts/m is imposed perpendicular to the incident ion beam direction and to the channeling planes in the crystal. The results obtained are discussed and compared to the effects due to the fringe field outside the crystal, differential cation-anion movement, movement of interplanar impurities, the piezoelectric strain and movement or creation of crystal defects on ion channeling.

Influence of crystal defects on the irreversibility line of YBa2Cu3O7-x single crystals

1991 ◽  
Vol 84 (1) ◽  
pp. 37-42 ◽  
Author(s):  
Ch. Neumann ◽  
Ch. Heinzel ◽  
P. Ziemann ◽  
K. Fischer ◽  
W. Gawalek
Keyword(s):  
Single Crystals ◽  
Crystal Defects ◽  
Irreversibility Line

Relative Helicity and Jog Densities in Continuum Descriptions of Dislocations

MRS Advances ◽  
2016 ◽  
Vol 1 (25) ◽  
pp. 1847-1852 ◽  
Author(s):  
Thomas Hochrainer
Keyword(s):  
Single Crystals ◽  
Crystal Defects ◽  
Slip Systems ◽  
Dislocation Theory ◽  
View Point ◽  
Current Contribution ◽  
Topological Measure

ABSTRACTDislocations are line like crystal defects mediating plasticity in single crystals. In the current contribution we review classical continuum concepts of dislocation theory from a topological view point. Subsequently, we introduce a new measure for the density of jogs mutually impaired on each other by dislocations on different slip systems. This jog density is closely related to a topological measure of the interlinkage of the dislocations on the involved slip systems, known as relative helicity in other branches of physics.

Study of structural and ferromagnetic resonance properties of spinel lithium ferrite (LiFe5O8) single crystals

2015 ◽  
Vol 117 (23) ◽  
pp. 233907 ◽  
Author(s):  
Neha Pachauri ◽  
Behrouz Khodadadi ◽  
Matthias Althammer ◽  
Amit V. Singh ◽  
B. Loukya ◽  
...  
Keyword(s):  
Single Crystals ◽  
Ferromagnetic Resonance ◽  
Lithium Ferrite ◽  
Resonance Properties

Domains and crystal defects in flux-grown gallium-substituted YIG single crystals

1980 ◽  
Vol 15-18 ◽  
pp. 1322-1324 ◽  
Author(s):  
C. Mazuré-Espejo ◽  
M. Schlenker ◽  
J. Baruchel ◽  
J.C. Peuzin ◽  
J. Daval
Keyword(s):  
Single Crystals ◽  
Crystal Defects

The Growth of SiC Crystals from CoSi Molten Alloy Fluxes

2006 ◽  
Vol 514-516 ◽  
pp. 343-347
Author(s):  
Ming Xia Gao ◽  
Yi Pan ◽  
Filipe J. Oliveira ◽  
G.Y. Yang ◽  
Joaquim M. Vieira
Keyword(s):  
Liquid Phase ◽  
Single Crystals ◽  
Growth Mechanism ◽  
Crystal Defects ◽  
Liquid Phase Sintering ◽  
Molten Alloy ◽  
Infiltration Process ◽  
Melt Infiltration ◽  
Powder Compacts ◽  
Porous Sic

The growth of SiC single crystals from SiC saturated Co-Si molten alloy fluxes is reported. Experiments were performed by two routes: liquid phase sintering of CoSi/SiC and Si/Co/SiC powder compacts and melt infiltration of CoSi alloy into porous SiC powder preforms. Results showed that euhedral SiC crystals, many of which appeared as polygonal or plate shaped single crystals, grew from the SiC saturated CoSi molten alloy. The largest SiC crystals exceed half millimetre in size, after 25h of isothermal dwelling at 1700°C in the melt infiltration process. The nature of the growth mechanism, the crystal defects and the effects of constituent materials, temperature and time on the abnormal grain growth of SiC single crystals are further discussed.

scholarly journals Analysis of Cubic Boron Nitride Single Crystal Defects Growth under High Temperature and High Pressure

2020 ◽  
Vol 2020 ◽  
pp. 1-6
Author(s):  
Lichao Cai ◽  
Bin Xu ◽  
Meizhe Lv ◽  
Feng Jia ◽  
Xingdong Yuan
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Boron Nitride ◽  
Single Crystals ◽  
Growth Mechanism ◽  
Cubic Boron Nitride ◽  
Crystal Defects ◽  
Synthetic Process ◽  
Growth Defects ◽  
Hole Defects

Cubic boron nitride (cBN) single crystals are synthesized under high temperature and high pressure in the Li-based system. The growth defects on hexagonal and triangular (111) surfaces of cBN single crystals after rapid cooling are discussed systemically for the first time using the atomic force microscope. Some impurity particles, triangle cone hole defects, lamellar-fault structures, and big steps are obvious on the surfaces of cBN single crystals. The formation mechanism of these defects is analyzed briefly at the synthetic process of cBN single crystals, and the growth mechanism of cBN single crystals transform from the two-dimensional growth to dislocation growth mechanism under high temperature and high pressure.

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