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The unique properties of single crystals are considered. The anisotropic properties of single crystals, and the relation between crystal orientation and the fatigue life and slip systems of the crystals are examined. The effect of raft formation on the creep-rupture life of the crystals is studied. Proposed research on the properties of and new applications for single crystals is discussed.
The nucleation and growth of diamond crystals on single-crystal copper surfaces implanted with carbon ions is studied. Microwave plasma-enhanced chemical-vapor deposition is used for diamond growth. The single-crystal copper substrates were implanted either at room or elevated temperature with carbon ions prior to diamond nucleation. This procedure leads to the formation of a graphite film on the copper surface which greatly enhances diamond crystallite nucleation. A simple lattice model is constructed for diamond growth on graphite as 111 line (diamond) parallel to 0001 line (graphite) and 110 line (diamond) parallel to 1 1 -2 0 (graphite).
Single crystal nickel-base superalloys used as turbine engine blades can have much higher creep and fatigue resistance than many polycrystalline superalloys due to the absence of weak grain boundaries as well as the ability to orient the blades in the primary loading direction on to the low elastic modulus [001] orientation, which significantly lowers the stresses imposed on the blades. However, grain defects can occur in these crystals, impairing these advantages. In the present study, fatigue tests of a single crystal superalloy uncovered unexpected defective grains in the test specimens, which initiated premature fatigue failures. The characteristics of these defective grains and the associated failures were evaluated and related to the observed fatigue lives.
We demonstrate two-dimensional photonic crystal cavities operating at telecommunication wavelengths in a single-crystal diamond membrane. We use a high-optical-quality and thin (~300 nm) diamond membrane, supported by a polycrystalline diamond frame, to realize fully suspended two-dimensional photonic crystal cavities with a high theoretical quality factor of ~8 × 10 6 and a relatively small mode volume of ~2(λ/n) 3 . The cavities are fabricated in the membrane using electron-beam lithography and vertical dry etching. We observe cavity resonances over a wide wavelength range spanning the telecommunication O- and S-bands (1360–1470 nm) with Q factors of up to ~1800. Our method paves the way for on-chip diamond nanophotonic applications in the telecommunication-wavelength range.
A structural model of the nanocomposite consisting of one-dimensional (1D) {alpha}-SnF{sub 2} single crystals and single-wall carbon nanotubes (SWCNTs) is proposed. The main cationic motif is revealed in the structure of monoclinic modification: two-layer packing of tin cations along the [283] direction. Four theoretical structural projections of a 1D crystal on the plane parallel to the [283] direction are determined and described. A fragment of the {alpha}-SnF{sub 2} structure in an SWCNT (with a channel diameter of 1.02 nm) is calculated. High-resolution electron microscopy (HREM) images are modeled. These images correspond to the actually observed HREM patterns.
Lithium niobate single crystals doped with lanthanides (Gd, Er) and nominally pure single crystals of congruent and stoichiometric compositions have been grown under time-dependent thermal conditions. Regular growth domain microstructures and periodic nanostructures have been investigated by optical microscopy and atomic force microscopy with a step from 10 to 100 nm. Comparative investigations of the Raman spectra of lithium niobate single crystals of different compositions have been performed.
Large single crystals of ZrAs{sub x}Se{sub y} (x>y, x+y{<=}2, PbFCl type of structure, space group P4/nmm) were grown by Chemical Transport. Structural details were studied by single crystal neutron diffraction techniques at various temperatures. One single crystal specimen with chemical composition ZrAs{sub 1.595(3)}Se{sub 0.393(1)} was studied at ambient temperature (R1=5.10 %, wR2=13.18 %), and a second crystal with composition ZrAs{sub 1.420(3)}Se{sub 0.560(1)} was investigated at 25 K (R1=2.70%, wR2=5.70 %) and 2.3 K (R1=2.30 %, wR2=4.70 %), respectively. The chemical compositions of the crystals under investigation were determined by wavelength dispersive X-ray spectroscopy. The quantification of trace elements was carried out by Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry. According to the crystal structure refinements the crystallographic 2a site is occupied by As, together with a significant amount of vacancies. One of the 2c sites is fully occupied by As and Se (random distribution). With respect to the fractional coordinates of the atoms, the crystal structure determinations based on the data obtained at 25.0 K and 2.3 K did not show significant deviations from ambient temperature results. The temperature dependence of the displacement parameters indicates a static displacement of As on the 2a sites (located on the (0 0 1) planes) for all temperatures. No indications for any occupation of interstitial sites or the presence of vacancies on the Zr (2a) site were found. - Graphical abstract: Large single crystals of ZrAs{sub x}Se{sub y} grown by Chemical Transport to study structural details as the As-Se order scheme by single crystal neutron diffraction.
LaNiO 3− δ single crystals have been obtained via high pressure floating zone growth under 149 bar of oxygen pressure. We find a radial gradient in the magnetic properties of specimens extracted from the as-grown boule, which we correlate with the appearance of ordered oxygen vacancy structures. This radial oxygen inhomogeneity has been characterized systematically using a combination of magnetization and X-ray scattering measurements. We establish the presence of rhombohedral ( R 3 ¯ c ), oxygen stoichiometric specimens at the periphery of the boule and the presence of a dilute concentration of ordered oxygen-deficient orthorhombic La 2 Ni 2 O 5 in the center. Furthermore, we demonstrate that the as-grown, oxygen-deficient central regions of the crystal can be annealed under high oxygen pressure, without loss of crystallinity, into fully oxygenated LaNiO 3 , recovering magnetic properties that are characteristic of stoichiometric specimens from the exterior region of the crystal. Thus, single crystals of LaNiO 3− δ possess oxygen content that can be reversibly modified under oxidizing and reducing conditions.
Highlights: • A new semiorganic single crystal of LSO grown by slow evaporation technique. • Morphological studies of the LSO crystal deduced by BFDH law. • In the UV–vis spectrum wide transparent region and large band gap were found. • SHG is equal to KDP crystal and d{sub 33} was found to be equal to 6pC/N. • Grown crystal belongs to softer category. - Abstract: New semiorganic crystal of lithium sulfate monohydrate oxalate (LSO) for nonlinear application was synthesized by controlled slow evaporation method. The growth rate of various planes of the grown crystal was estimated by morphological study. Single crystal XRD analysis confirmed that the crystal belongs to triclinic lattice with space group P1. High transparency (∼95%) with large band gap (4.57 eV) was analyzed by UV–vis studies. FTIR and Raman spectroscopy were used to identify various functional groups present in the LSO crystal. SHG efficiency was found to be equal to the KDP crystal. Thermal stability (up to 117.54 °C) and melting point (242 °C) of the crystal were studied by TG-DTA. In dielectric measurements, the value of dielectric constant decreases with increase in frequency. Hardness studies confirmed soft nature of crystals. The piezoelectric coefficient was found to be 6pC/N along [0 0 1].
Highlights: • Transparent YAG and pale pink Nd:YAG single crystals were produced by the Czochralski technique. • Growth mechanisms and shape of the liquid/solid interface and incorporation of Nd{sup 3+} were studied. • The structure of the crystals was investigated by X-ray diffraction, Raman and IR spectroscopy. • The 15 Raman and 17 IR modes were observed. • The obtained YAG and Nd:YAG single crystals were without core and of good optical quality. - Abstract: Yttrium aluminum garnet (YAG, Y{sub 3}Al{sub 5}O{sub 12}) and yttrium aluminum garnet doped with neodymium (Nd:YAG) single crystals were grown by the Czochralski technique. The critical diameter and the critical rate of rotation were calculated. Suitable polishing and etching solutions were determined. As a result of our experiments, the transparent YAG and pale pink Nd:YAG single crystals were produced. The obtained crystals were studied by X-ray diffraction, Raman and IR spectroscopy. The crystal structure was confirmed by XRD. The 15 Raman and 17 IR modes were observed. The Raman and IR spectroscopy results are in accordance with X-ray diffraction analysis. The obtained YAG and Nd:YAG single crystals were without core and of good optical quality. The absence of a core was confirmed by viewing polished crystal slices. Also, it is important to emphasize that the obtained Nd:YAG single crystal has a concentration of 0.8 wt.% Nd{sup 3+} that is characteristic for laser materials.
Cuprous iodide (CuI) crystals are grown by slow evaporation technique in three different solvents. Large CuI single crystals with dimensions of 7.5 mm x 5 mm x 3 mm are obtained in pure acetonitrile solvent at 40 {sup o}C. The as-grown crystals are analyzed by X-ray diffraction, energy-dispersive X-ray analysis, differential scanning calorimetry, current-voltage characteristic and photoluminescence spectrum. The results show that the CuI crystal has the zinc-blende structure with no secondary phase. The elemental Cu/I ratio is 1.09:1. The melting point of the crystal is 875 K and two phase transitions occur from room temperature to its melting point. The electrical conductivity of CuI platelet crystal is in the range of 1.11-2.38 {Omega}{sup -1} cm{sup -1}. Under ultraviolet excitation, the CuI crystals exhibit three emission bands with peak positions at 426, 529 and 671 nm. The nature of the luminescence is discussed.
A production method and structure for a thin-film GaAs crystal for a solar cell on a single-crystal silicon substrate (10) comprising the steps of growing a single-crystal interlayer (12) of material having a closer match in lattice and thermal expansion with single-crystal GaAs than the single-crystal silicon of the substrate, and epitaxially growing a single-crystal film (14) on the interlayer. The material of the interlayer may be germanium or graded germanium-silicon alloy, with low germanium content at the silicon substrate interface, and high germanium content at the upper surface. The surface of the interface layer (12) is annealed for recrystallization by a pulsed beam of energy (laser or electron) prior to growing the interlayer. The solar cell structure may be grown as a single-crystal n.sup.+ /p shallow homojunction film or as a p/n or n/p junction film. A Ga(Al)AS heteroface film may be grown over the GaAs film.
Ultrasonic attenuation in superconducting Hg single crystals, polycrystals and single crystals with Cd impurity compared to BCS theory
Single-crystal high-nickel oxide with an integral structure can prevent intergranular cracks and the associated detrimental reactions. Yet, its low surface-to-volume ratio makes surficial degradation a more critical factor in electrochemical performance. Herein, artificial proton-rich (ammonium bicarbonate) shell is successfully introduced on the nickel-rich LiNi 0.92 Co 0.06 Mn 0.02 O 2 single crystals for in situ electrochemically conversing into inorganic maskant to enhance stability of cathode. The process is that the surficial enriched proton, once released from the ammonium bicarbonate shell (proton reservoir) during 1st charge, is immediately captured by LiPF 6 , in situ electrochemically conversing to LiF and Li 3 PO 4 sub-nano particle dense maskant (sub-nano F-&P-maskant). The in situ formed compact nano F-&P-maskant significantly resists the cathode against electrolyte attack and improves the surface stability of particles during long-term cycling. Consequently, this surface modification enables 95% capacity retention after 100 cycles at a high voltage of 4.5 V in the half cell and 83% capacity retention after 800 cycles in the full cell. In conclusion, this work demonstrates a strategy for reconstructing the protective layer using the rational design of surficial enriched proton shells for advanced lithium batteries.
The Fe-S system was explored in a laser-heated diamond-anvil cell at 89(2) GPa and 2380(120) K to better understand the phase stability of Fe 2 S. Upon temperature quenching, crystallites of Fe 2 S were identified, and their structure was investigated using single-crystal X-ray diffraction techniques. At these conditions, Fe 2 S adopts the C23 structure (anti-PbCl 2 , Co 2 P) with space group Pnma (Z = 4). This structure consists of columns of corner-sharing, FeS 4 tetrahedra, and columns of edge-sharing FeS 5 square pyramids linked along edges in the b direction. Sulfur is in ninefold coordination with Fe. This work marks the first high-pressure structural solution and refinement of Fe 2 S synthesized in a multigrain Fe+FeS sample at 90 GPa and 2400 K and establishes the stability of C23 Fe 2 S at these conditions. A previous powder diffraction study reports an orthorhombic Fe 2 S phase with a C37, Co 2 Si-like unit cell above 190 GPa. A C23–C37 structural transition is inferred to explain the previously observed unit-cell parameters at higher pressures and temperatures. These results highlight the utility of applying single-crystal X-ray diffraction techniques to high P-T multigrain samples to explore the structural properties of iron-rich phases in Earth and planetary cores.
A hydrothermal route to single crystals of rare earth stannates RE 2 Sn 2 O 7 (RE = La–Lu) in the cubic pyrochlore structure is reported. Growth reactions were performed in aqueous fluids at 700 °C and 200 MPa with CsF mineralizers in concentrations ranging from 0 to 30 M, with 20 M CsF providing the most consistent results. Single crystals of the entire range of lanthanides were grown and characterized by single crystal X-ray diffraction and found to be isostructural in the Fd $\bar{3}$ m space group. The unit cell sizes range from 10.7106(16) Å for La 2 Sn 2 O 7 to 10.3005(9) Å for Lu 2 Sn 2 O 7 . Both the unit cell size and RE–O distances are found to be essentially linear with respect to the ionic radius of the rare earth ion. The high quality diffraction data strongly indicates that there is very little site disorder or lattice defects in the sample. Of specific interest is the synthesis and single crystal growth of Ce 2 Sn 2 O 7 , which represents one of the few f 1 pyrochlore samples. Specific heat measurements were obtained down to 50 mK on both Yb 2 Sn 2 O 7 and Ce 2 Sn 2 O 7 , with the Yb material displaying a single sharp peak at 138 mK suggesting that the sample does not contain any site disorder or “lattice stuffing”. The Ce analog demonstrates only a broad featureless transition below 100 mK, with this lack of long-range magnetic order consistent with quantum spin liquid behavior
Single-crystal materials have attracted growing interest in battery research due to their well-defined crystallographic orientation, absence of grain boundaries, and enhanced mechanical and electrochemical stability. This Review provides a comprehensive overview of recent advances in the synthesis, structural evolution, and performance optimization of single-crystal electrodes and solid electrolytes. Particular focus is placed on the application of advanced X-ray diffraction (XRD) techniques, including operando synchrotron diffraction, reciprocal space mapping, and Bragg coherent diffraction imaging, which have enabled in-depth investigations of lattice strain, cation disorder, phase transitions, and defect formation. Representative case studies across Ni-rich layered oxides, spinel-type cathodes, and garnet-based electrolytes are examined to highlight the structural features unique to single crystals. Additionally, the synergistic integration of XRD with machine learning, tomography, and spectroscopy is discussed as a powerful direction for real-time analysis and predictive modeling. Furthermore, these insights provide critical guidance for the rational design of high-performance single-crystal materials in lithium, sodium, and solid-state battery systems.
Research on the growth of single crystals of the III-V compound indium antimonide was pursued in order to gain a firsthand knowledge of some factors which govern the growth of single crystals of this compound. These studies were conducted using a standard Czochralski crystal pulling furnace. This type of furnace allows crystals to be formed without being constrained to a crucible. Several factors were found to have a large detrimental effect on the growth of single crystals of indium antimonide, the most important of which seems to be the degree to which the environment surrounding the crystal during growth can be controlled. Ways to overcome these effects were determined and are outlined.