Next Issue
Volume 7, April
Previous Issue
Volume 7, February
 
 

Crystals, Volume 7, Issue 3 (March 2017) – 31 articles

Cover Story (view full-size image): We explored single crystalline Yb2CoMnO6 and Lu2CoMnO6 grown by the flux method. They exhibit strong interrelationship between magnetic and dielectric properties as type-II multiferroics. The intrinsically coupled magnetic and dielectric states driven by symmetric exchange strictions were thoroughly investigated and discussed in detail. View this paper.
  • Issues are regarded as officially published after their release is announced to the table of contents alert mailing list.
  • You may sign up for e-mail alerts to receive table of contents of newly released issues.
  • PDF is the official format for papers published in both, html and pdf forms. To view the papers in pdf format, click on the "PDF Full-text" link, and use the free Adobe Reader to open them.
Order results
Result details
Section
Select all
Export citation of selected articles as:
9354 KiB  
Review
Borates—Crystal Structures of Prospective Nonlinear Optical Materials: High Anisotropy of the Thermal Expansion Caused by Anharmonic Atomic Vibrations
by Rimma Bubnova, Sergey Volkov, Barbara Albert and Stanislav Filatov
Crystals 2017, 7(3), 93; https://doi.org/10.3390/cryst7030093 - 22 Mar 2017
Cited by 42 | Viewed by 8916
Abstract
In the present study the thermal structure evolution is reviewed for known nonlinear optical borates such as β-BaB2O4, LiB3O5, CsLiB6O10, Li2B4O7, K2Al [...] Read more.
In the present study the thermal structure evolution is reviewed for known nonlinear optical borates such as β-BaB2O4, LiB3O5, CsLiB6O10, Li2B4O7, K2Al2B2O7, and α-BiB3O6, based on single-crystal and powder X-ray diffraction data collected over wide temperature ranges. Temperature-dependent measurements of further borates are presented for the first time: α-BaB2O4 (295–673 K), β-BaB2O4 (98–693 K), LiB3O5 (98–650 K) and K2Al2B2O7 (98–348 K). In addition to the established criteria for nonlinear optical (NLO) properties of crystals, here the role of the anisotropy and anharmonicity of the thermal vibrations of atoms is analysed as well as changes in their coordination spheres and the anisotropy of the thermal expansion of the crystal structure. Non-centrosymmetric borates, especially those that have NLO properties, often show distinct anisotropies for each cation in comparison to centrosymmetric borates. All considered NLO borates contain BO3 triangles, which are the principal cause of the strong anisotropy of the thermal expansion. Full article
Show Figures

Graphical abstract

3457 KiB  
Article
Two Organic Cation Salts Containing Tetra(isothiocyanate)cobaltate(II): Synthesis, Crystal Structures, Spectroscopic, Optical and Magnetic Properties
by Zheng Zhang, Junwei Xu, Sisi Yan, Yangli Chen, Yan Wang, Zhuo Chen and Chunlin Ni
Crystals 2017, 7(3), 92; https://doi.org/10.3390/cryst7030092 - 22 Mar 2017
Cited by 11 | Viewed by 4343
Abstract
Single crystals of two hybrid organic-inorganic molecular solids, benzyl pyridinium tetra(isothiocyanate)cobalt ([BzPy]2[Co(NCS)4]) (1) and benzyl quinolinium tetra(isothiocyanate)cobalt ([BzQl]2[Co(NCS)4]) (2), were grown using a slow evaporation growth technique at room temperature and [...] Read more.
Single crystals of two hybrid organic-inorganic molecular solids, benzyl pyridinium tetra(isothiocyanate)cobalt ([BzPy]2[Co(NCS)4]) (1) and benzyl quinolinium tetra(isothiocyanate)cobalt ([BzQl]2[Co(NCS)4]) (2), were grown using a slow evaporation growth technique at room temperature and their IR, UV-Vis, X-ray crystal structures, luminescence, and magnetism were reported. The crystal structural analysis revealed that two molecular solids crystallize in the monoclinic space group P21/c of 1 and P21/n of 2. The cations form a dimer through weak C–H···π/π···π interactions in 1 and 2, and the adjacent cation (containing N(6) atom) in 2 forms a columnar structure through π···π weak interactions between the quinoline and benzene rings, while the anions in 1 form a layer structure via short S···Co interactions. The anions (A) and cations (C) are arranged alternatively into a column in the sequence of ···A–CC–A–CC–A··· for 1, while the two anions and cationic dimer in 2 form an alliance by the C–H···π, C–H···S and C–H···N hydrogen bonds. A weak S···π interaction was found in 1 and 2. The two molecular solids show a broad fluorescence emission around 400 nm in the solid state at room temperature, and weak antiferromagnetic coupling behavior when the temperature is lowered. Full article
(This article belongs to the Section Crystal Engineering)
Show Figures

Graphical abstract

16878 KiB  
Article
Growth and Physical Properties of SrxCa1−xCrO3 Single Crystals
by Lipeng Cao, Aizi Jin, Changzhi Gu, Haiyang Bai, Youwen Long, Richeng Yu, Liqing Pan and Changqing Jin
Crystals 2017, 7(3), 91; https://doi.org/10.3390/cryst7030091 - 21 Mar 2017
Cited by 8 | Viewed by 4516
Abstract
Perovskites SrxCa1−xCrO3 attract much attention due to the controversy on the anomalous electronic state. In this study, we synthesized a series of SrxCa1−xCrO3 (0 ≤ x ≤ 1) single crystals under high pressure [...] Read more.
Perovskites SrxCa1−xCrO3 attract much attention due to the controversy on the anomalous electronic state. In this study, we synthesized a series of SrxCa1−xCrO3 (0 ≤ x ≤ 1) single crystals under high pressure and high temperature conditions with self-oxidization. The crystal structure was determined using X-ray diffraction (XRD). With the increase of x, the structure transformed from orthorhombic to tetragonal to cubic. Antiferromagnetism was observed except for SrCrO3, and the TN decreased with increased x. All samples demonstrated semiconductive behavior by electrical resistivity measurement. Full article
(This article belongs to the Special Issue Crystal Growth for Optoelectronic and Piezoelectric Applications)
Show Figures

Figure 1

1677 KiB  
Article
The Influence of Conductive Nanodomain Walls on the Photovoltaic Effect of BiFeO3 Thin Films
by Zilong Bai, Yan Zhang, Huizhen Guo and Anquan Jiang
Crystals 2017, 7(3), 81; https://doi.org/10.3390/cryst7030081 - 21 Mar 2017
Cited by 1 | Viewed by 3896
Abstract
Two Planar Pt electrodes with an inter-electrode distance of about 100 nm were fabricated at the surface of BiFeO3 thin films, which allow the manipulation of ferroelectric domain switching at nanoscale. This electrode configuration was pursued to study conductive domain-wall influence on [...] Read more.
Two Planar Pt electrodes with an inter-electrode distance of about 100 nm were fabricated at the surface of BiFeO3 thin films, which allow the manipulation of ferroelectric domain switching at nanoscale. This electrode configuration was pursued to study conductive domain-wall influence on the photovoltaic current in BiFeO3 thin films. Modulations of short-circuit photovoltaic current and hysteretic conductive switching behaviors were found in the above nanodevices, accompanied by the generation of the conductive domain walls connecting two gapped electrodes. Our technique provides a new method to configure ferroelectric domains, where the influence of the conductive domain walls on the photovoltaic effect is preeminent. Full article
(This article belongs to the Special Issue Multiferroics Crystals)
Show Figures

Figure 1

2510 KiB  
Article
X-ray Structures of Succinimidyl Halobenzoates
by Constantin Mamat, Daniel Holger Weiß and Martin Köckerling
Crystals 2017, 7(3), 90; https://doi.org/10.3390/cryst7030090 - 20 Mar 2017
Cited by 1 | Viewed by 4092
Abstract
The crystal and molecular structures of five succinimidyl halobenzoates are reported. Corresponding derivatives with the respective halo-radionuclide (18F, 76Br, 123I/124I/125I/131I) were prepared and used for the radiolabeling of biologically active (macro-)molecules (peptides, proteins, [...] Read more.
The crystal and molecular structures of five succinimidyl halobenzoates are reported. Corresponding derivatives with the respective halo-radionuclide (18F, 76Br, 123I/124I/125I/131I) were prepared and used for the radiolabeling of biologically active (macro-)molecules (peptides, proteins, antibodies) under mild labeling conditions. All compounds were crystalized from petroleum ether/ethyl acetate mixtures. Full article
Show Figures

Figure 1

1729 KiB  
Article
Crystal Growth and Glass-Like Thermal Conductivity of Ca3RE2(BO3)4 (RE = Y, Gd, Nd) Single Crystals
by L. V. Gudzenko, M. B. Kosmyna, A. N. Shekhovtsov, W. Paszkowicz, A. Sulich, J. Z. Domagała, P. A. Popov and S. A. Skrobov
Crystals 2017, 7(3), 88; https://doi.org/10.3390/cryst7030088 - 17 Mar 2017
Cited by 14 | Viewed by 4873
Abstract
Crystal growth and thermal properties of binary borates, Ca3RE2(BO3)4 (RE = Y, Gd, Nd), are considered promising crystals for laser applications. These single crystals were grown by the Czochralski method. The crystal and defect structure were [...] Read more.
Crystal growth and thermal properties of binary borates, Ca3RE2(BO3)4 (RE = Y, Gd, Nd), are considered promising crystals for laser applications. These single crystals were grown by the Czochralski method. The crystal and defect structure were characterized. Volumetric chemical methods without prior separation of the components were developed and applied for the determination of the dependence of chemical compositions of the crystals on the growth conditions. The thermal conductivity was investigated in the 50–300 K range. The character of the temperature dependence of thermal conductivity was found to be similar to that of glass. The possible reasons of the observed features of the thermal conductivity were analyzed. Full article
(This article belongs to the Special Issue Crystal Growth for Optoelectronic and Piezoelectric Applications)
Show Figures

Figure 1

2170 KiB  
Article
Application of the Improved Inclusion Core Model of the Indentation Process for the Determination of Mechanical Properties of Materials
by Boris A. Galanov, Yuly V. Milman, Svetlana I. Chugunova, Irina V. Goncharova and Igor V. Voskoboinik
Crystals 2017, 7(3), 87; https://doi.org/10.3390/cryst7030087 - 16 Mar 2017
Cited by 19 | Viewed by 4351
Abstract
The improved Johnson inclusion core model of indentation by conical and pyramidal indenters in which indenter is elastically deformed and a specimen is elastoplastically deformed under von Mises yield condition, was used for determination of mechanical properties of materials with different types of [...] Read more.
The improved Johnson inclusion core model of indentation by conical and pyramidal indenters in which indenter is elastically deformed and a specimen is elastoplastically deformed under von Mises yield condition, was used for determination of mechanical properties of materials with different types of interatomic bond and different crystalline structures. This model enables us to determine approximately the Tabor parameter С = НМ/YS (where НМ is the Meyer hardness and YS is the yield stress of the specimen), size of the elastoplastic zone in the specimen, effective apex angle of the indenter under load, and effective angle of the indent after unloading. It was shown that the Tabor parameter and the size of elastoplastic deformation zone increase monotonically with the increase of the plasticity characteristic indentation test results significantly more informative. Full article
(This article belongs to the Special Issue Crystal Indentation Hardness)
Show Figures

Figure 1

7052 KiB  
Article
Strength of Alkane–Fluid Attraction Determines the Interfacial Orientation of Liquid Alkanes and Their Crystallization through Heterogeneous or Homogeneous Mechanisms
by Yuqing Qiu and Valeria Molinero
Crystals 2017, 7(3), 86; https://doi.org/10.3390/cryst7030086 - 15 Mar 2017
Cited by 29 | Viewed by 7491
Abstract
Alkanes are important building blocks of organics, polymers and biomolecules. The conditions that lead to ordering of alkanes at interfaces, and whether interfacial ordering of the molecules leads to heterogeneous crystal nucleation of alkanes or surface freezing, have not yet been elucidated. Here [...] Read more.
Alkanes are important building blocks of organics, polymers and biomolecules. The conditions that lead to ordering of alkanes at interfaces, and whether interfacial ordering of the molecules leads to heterogeneous crystal nucleation of alkanes or surface freezing, have not yet been elucidated. Here we use molecular simulations with the united-atom OPLS and PYS alkane models and the mW water model to determine what properties of the surface control the interfacial orientation of alkane molecules, and under which conditions interfacial ordering results in homogeneous or heterogeneous nucleation of alkane crystals, or surface freezing above the melting point. We find that liquid alkanes present a preference towards being perpendicular to the alkane–vapor interface and more parallel to the alkane–water interface. The orientational order in the liquid is short-ranged, decaying over ~1 nm of the surface, and can be reversed by tuning the strength of the attractions between alkane and the molecules in the other fluid. We show that the strength of the alkane–fluid interaction also controls the mechanism of crystallization and the face of the alkane crystal exposed to the fluid: fluids that interact weakly with alkanes promote heterogeneous crystallization and result in crystals in which the alkane molecules orient perpendicular to the interface, while crystallization of alkanes in the presence of fluids, such as water, that interact more strongly with alkanes is homogeneous and results in crystals with the molecules oriented parallel to the interface. We conclude that the orientation of the alkanes at the crystal interfaces mirrors that in the liquid, albeit more pronounced and long-ranged. We show that the sign of the binding free energy of the alkane crystal to the surface, ΔGbind, determines whether the crystal nucleation is homogeneous (ΔGbind ≥ 0) or heterogeneous (ΔGbind < 0). Our analysis indicates that water does not promote heterogeneous crystallization of the alkanes because water stabilizes more the liquid than the crystal phase of the alkane, resulting in ΔGbind > 0. While ΔGbind < 0 suffices to produce heterogeneous nucleation, the condition for surface freezing is more stringent, ΔGbind < −2 γxl, where γxl is the surface tension of the liquid–crystal interface of alkanes. Surface freezing of alkanes is favored by their small value of γxl. Our findings are of relevance to understanding surface freezing in alkanes and to develop strategies for controlling the assembly of chain-like molecules at fluid interfaces. Full article
(This article belongs to the Special Issue Advances in Computer Simulation Studies on Crystal Growth)
Show Figures

Figure 1

2628 KiB  
Article
The Syntheses, Crystal Structure and Luminescence Properties of Cone-Like Octadentate Europium (III) Complexes with Four Short Alkoxy Substituents
by Tetsuji Moriguchi, Satoshi Hirosaki, Venkataprasad Jalli, Akihiko Tsuge and Kenji Yoza
Crystals 2017, 7(3), 85; https://doi.org/10.3390/cryst7030085 - 13 Mar 2017
Cited by 27 | Viewed by 4127
Abstract
Treatment of 1-(4′-methoxy or ethoxy phenyl)-4,4,4-trifluoro-1,3-butanedione with europium (III) chloride in the presence of piperidine resulted in the halide ligands exchange yielded new piperidinium tetrakis{1-(4′-methoxy or ethoxy phenyl)-4,4,4-trifluoro-1,3-butanedionato} europate (III) complexes 2a and 2b. Complexes 2a and 2b have been characterized by elemental [...] Read more.
Treatment of 1-(4′-methoxy or ethoxy phenyl)-4,4,4-trifluoro-1,3-butanedione with europium (III) chloride in the presence of piperidine resulted in the halide ligands exchange yielded new piperidinium tetrakis{1-(4′-methoxy or ethoxy phenyl)-4,4,4-trifluoro-1,3-butanedionato} europate (III) complexes 2a and 2b. Complexes 2a and 2b have been characterized by elemental analysis, 1H NMR spectroscopy, and FAB-MS, and their absolute structures were determined by single crystal X-ray diffraction analysis. The complexes 2a and 2b have the monoclinic space groups C2/c (No. 15, 4′-substituent = OCH3) and with P − 1 (No. 2, 4′-substituent = OC2H5), respectively. X-ray analysis results showed that eight coordinate structures of the complexes 2a and 2b have conelike structures, like calix[4]arenes, but their structures were slightly different due to the crystal packing and the existence of the solvent molecule. The complexes 2a and 2b exhibited identical, strong photoluminescence emissions in the solution phase. Full article
(This article belongs to the Special Issue Luminescent Properties of Lanthanoid Doped Crystals)
Show Figures

Figure 1

10826 KiB  
Article
A Structural Analysis of Spiropyran and Spirooxazine Compounds and Their Polymorphs
by Vanessa Kristina Seiler, Nikolay Tumanov, Koen Robeyns, Johan Wouters, Benoit Champagne and Tom Leyssens
Crystals 2017, 7(3), 84; https://doi.org/10.3390/cryst7030084 - 13 Mar 2017
Cited by 20 | Viewed by 7054
Abstract
In this work, crystal structures of commercially available photochromic compounds, i.e., spiropyrans and spirooxazines, were investigated by single-crystal X-ray diffraction. A total of five new structures were obtained via isothermal evaporation experiments under different conditions, namely 1,3,3-Trimethylindolino-benzopyrylospiran (I), 1,3,3-Trimethylindolinonaphtospirooxaxine (II), 1-(2-Hydroxyethyl)-3,3-dimethylindolino-6′-nitrobenzopyrylospiran (III), and [...] Read more.
In this work, crystal structures of commercially available photochromic compounds, i.e., spiropyrans and spirooxazines, were investigated by single-crystal X-ray diffraction. A total of five new structures were obtained via isothermal evaporation experiments under different conditions, namely 1,3,3-Trimethylindolino-benzopyrylospiran (I), 1,3,3-Trimethylindolinonaphtospirooxaxine (II), 1-(2-Hydroxyethyl)-3,3-dimethylindolino-6′-nitrobenzopyrylospiran (III), and 1,3,3-Trimethylindolino-8′-methoxybenzopyrylospiran (IVa and IVb). Since the basic structure of a spiropyran/-oxazine does not present typical hydrogen bond accepting and donating groups, this study illustrates the importance of additional functional groups connected to this kind of molecules to induce specific intermolecular interactions. Our results show that possible hydrogen bonding interactions are rather weak due to the high steric demand of these compounds. These results are supported by a search of the Cambridge structural database focused on related structures. Full article
(This article belongs to the Special Issue Thermo- and Photochromic Molecular Crystals)
Show Figures

Graphical abstract

2403 KiB  
Article
Growth of High Quality Al-Doped CsLiB6O10 Crystals Using Cs2O-Li2O-MoO3 Fluxes
by Xianchao Zhu, Heng Tu, Ying Zhao and Zhanggui Hu
Crystals 2017, 7(3), 83; https://doi.org/10.3390/cryst7030083 - 13 Mar 2017
Cited by 5 | Viewed by 4830
Abstract
Abstract: High quality and large size Al-doped CsLiB6O10 (CLBO) single crystals have been successfully grown by top-seeded solution growth (TSSG) technique using Cs2O–Li2O–MoO3 fluxes. The advantages of this newly developed flux system were investigated by [...] Read more.
Abstract: High quality and large size Al-doped CsLiB6O10 (CLBO) single crystals have been successfully grown by top-seeded solution growth (TSSG) technique using Cs2O–Li2O–MoO3 fluxes. The advantages of this newly developed flux system were investigated by viscosity measurements and growth experiments. Al-doped CLBO presents a very high transmittance in the visible region and the weak absorption values at 1064 nm along a and c axes are only 140 and 50 ppm/cm, respectively. The measured LIDT of Al-doped CLBO at λ = 1064 nm and τ = 5.0 ns is 5.10 GW/cm2. Moreover, Al-doped CLBO exhibits an apparent enhancement of the hygroscopic nature in contrast with the undoped crystal as determined by the humidity experiments. Finally, a high fourth harmonic generation (FHG) conversion efficiency of 63% utilizing Al-doped CLBO has been achieved by a picosecond mode-locked Nd:YAG laser, the results also reveal that Al doping has no obvious impact on the FHG conversion efficiency. Full article
Show Figures

Figure 1

2869 KiB  
Article
The Effects of ACRT on the Growth of ZnTe Crystal by the Temperature Gradient Solution Growth Technique
by Liying Yin, Wanqi Jie, Tao Wang, Boru Zhou, Fan Yang and Ruihua Nan
Crystals 2017, 7(3), 82; https://doi.org/10.3390/cryst7030082 - 13 Mar 2017
Cited by 9 | Viewed by 4220
Abstract
A finite element method is used here to simulate the temperature field, the thermosolutal convection, the solute segregation, and the non-isothermal phase transformation during the growth of ZnTe crystal via the temperature gradient solution growth technique (TGSG) with an accelerated crucible rotation technique [...] Read more.
A finite element method is used here to simulate the temperature field, the thermosolutal convection, the solute segregation, and the non-isothermal phase transformation during the growth of ZnTe crystal via the temperature gradient solution growth technique (TGSG) with an accelerated crucible rotation technique (ACRT). Three different trapezoid-wave ACRT sequences are proposed, and their effects are examined from the views of the constitutional supercooling and the mixing of the solution. The solution in front of the growth interface can be fully mixed only during the constant rotation stage of the ACRT when there is a clockwise Ekman flow. An inappropriate ACRT can produce excessively strong clockwise and counterclockwise Ekman flows, and this results in constitutional supercooling in front of the central part of the growth interface at the beginning of the stop stage and in front of the peripheral part at the end of the constant rotation stage. By adjusting the acceleration rate of the ampoule rotation, the appropriate Ekman flows can be obtained to well mix the solution and avoid the constitutional supercooling. An appropriate ACRT sequence is provided, which can facilitate the mixing of the solution, avoid constitutional supercooling, and improve the growth interface morphology. Full article
(This article belongs to the Section Crystalline Materials)
Show Figures

Figure 1

8107 KiB  
Article
Synthesis, Crystal Structures, and Properties of Two Coordination Polymers Built from Imidazolyl and Carboxylate Ligands
by Xing-Zhe Guo, Zhi-You Zhang, Zi-Long Li, Shan-Shan Shi and Shui-Sheng Chen
Crystals 2017, 7(3), 73; https://doi.org/10.3390/cryst7030073 - 10 Mar 2017
Cited by 5 | Viewed by 4075
Abstract
Two new two-dimensional (2D) layer coordination polymers—namely, [Cd(L)2]n (1) and [Co(L)2(H2O)]n (2)—were synthesized by the reaction of corresponding metal salts with 3-(1H-imidazol-4-yl)benzoic acid (HL) incorporating 4-imidazolyl and [...] Read more.
Two new two-dimensional (2D) layer coordination polymers—namely, [Cd(L)2]n (1) and [Co(L)2(H2O)]n (2)—were synthesized by the reaction of corresponding metal salts with 3-(1H-imidazol-4-yl)benzoic acid (HL) incorporating 4-imidazolyl and carboxylate functional groups, and characterized by single-crystal X-ray diffraction, elemental analysis, IR spectroscopy, and powder X-ray diffraction (PXRD). Complex 1 is a 2D network with (4, 4) topology, while 2 is a typical 63-hcb topology net. Complex 1 exhibits intense light blue emission in the solid state at room temperature. Full article
(This article belongs to the Section Crystalline Materials)
Show Figures

Figure 1

5075 KiB  
Article
Interface Crystallization of Ceria in Porous Silica Films for Solar Applications
by Gundula Helsch and Joachim Deubener
Crystals 2017, 7(3), 80; https://doi.org/10.3390/cryst7030080 - 08 Mar 2017
Cited by 1 | Viewed by 4192
Abstract
Antireflective (AR) coatings with photocatalytic activity for solar cover glasses are extensively investigated at present, mostly in multilayer systems including titania. In this study, bifunctional single coats from porous silica in combination with up to 33 mol % ceria were prepared by sol–gel [...] Read more.
Antireflective (AR) coatings with photocatalytic activity for solar cover glasses are extensively investigated at present, mostly in multilayer systems including titania. In this study, bifunctional single coats from porous silica in combination with up to 33 mol % ceria were prepared by sol–gel dip-coating on low-iron soda-lime float glass. After heat treatment for one hour at 350 °C, the coated glasses were characterized. Solar transmittance decreased with increasing ceria content, whereas photocatalytic activity increases. Crystallization of cubic ceria was detected by grazing incidence X-ray diffraction. Chemical depth profiling by secondary neutral mass spectrometry revealed the enrichment of cerium at the coating surface as well as at the interface to the glass substrate. Self-assembled ceria crystallization at the interfaces resulted in a three-layered mesostructure of the coating, which was verified by field-emission scanning electron spectroscopy. Cubic ceria crystals at the interface act as a barrier for the sodium diffusion from the substrate, which prevents the poisoning of the photocatalyst, while those crystals at the surface act as an electron donor for photooxidation processes, both enabling adequate photocatalytic activity. The triple-layer architecture with the sequence of high/low/high refractive index materials allows for optical interference sustaining the AR-function. Full article
(This article belongs to the Special Issue Crystallization of Sol-Gel Derived Glasses)
Show Figures

Graphical abstract

2713 KiB  
Article
Synthesis, Crystal Structure, Magnetic Property and Photo-Induced Coloration of a One-Dimensional Chain Complex
by Qingguo Meng, Suqing Wang, Junhao Zhang, Rui Xun, Mingchao Chen and Jitao Lu
Crystals 2017, 7(3), 77; https://doi.org/10.3390/cryst7030077 - 08 Mar 2017
Cited by 60 | Viewed by 3796
Abstract
A novel photoactive complex was constructed from two non-photoactive ligands and cobalt (II) ions. Upon ultra violet (UV) irradiation (365 nm), the color of complex 1 changes from orange to violet. The ESR spectrum indicates that the photoactive phenomenon of complex 1 originates [...] Read more.
A novel photoactive complex was constructed from two non-photoactive ligands and cobalt (II) ions. Upon ultra violet (UV) irradiation (365 nm), the color of complex 1 changes from orange to violet. The ESR spectrum indicates that the photoactive phenomenon of complex 1 originates from an intermolecular energy transfer between the H5DDCPBA ligand and phenanthroline ligand. This photoactive complex shows high thermal stability according to the investigation of thermogravimetric analyses. In addition, the temperature dependence of magnetic susceptibilities for the orange complex 1 was also investigated systematically. Full article
(This article belongs to the Section Crystalline Materials)
Show Figures

Graphical abstract

1868 KiB  
Article
Cobalt-Substituted Seven-Layer Aurivillius Bi8Fe4Ti3O24 Ceramics: Enhanced Ferromagnetism and Ferroelectricity
by Zhiwei Lei, Tong Chen, Weigu Li, Min Liu, Wen Ge and Yalin Lu
Crystals 2017, 7(3), 76; https://doi.org/10.3390/cryst7030076 - 08 Mar 2017
Cited by 9 | Viewed by 4218
Abstract
In this work, Aurivillius-phase Bi8Fe4-xCoxTi3O24 (7-BFCT, 0 ≤ x ≤ 0.4) powders and ceramics were successfully prepared by the combination of citrate combustion and hot-press methods. X-ray diffraction (XRD) and high-resolution transmission electron [...] Read more.
In this work, Aurivillius-phase Bi8Fe4-xCoxTi3O24 (7-BFCT, 0 ≤ x ≤ 0.4) powders and ceramics were successfully prepared by the combination of citrate combustion and hot-press methods. X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) indicate a successful synthesis of the pure phase of the 7-BFCT ceramics, and all the samples showed a good seven-layer structure of the Aurivillius phase. Partial Fe substituted by Co was found to be effective to enhance both ferromagnetic and ferroelectric properties at room temperature, and the largest remnant magnetization (2Mr) of ~0.69 emu/g was revealed at the composition of x = 0.4. Zero field cooling and field cooling (ZFC-FC) magnetization measurement confirmed its magnetic transition occurring at a high temperature of ~750 K. Correspondingly, the enhanced ferroelectric properties of such Co-substituted ceramics were also investigated. Full article
(This article belongs to the Special Issue Multiferroics Crystals)
Show Figures

Graphical abstract

2078 KiB  
Article
Ferroelectric Liquid Crystal Dammann Grating by Patterned Photoalignment
by Fan Fan, Lishuang Yao, Xiaoqian Wang, Liangyu Shi, Abhishek K. Srivastava, Vladimir G. Chigrinov, Hoi-Sing Kwok and Shuangchun Wen
Crystals 2017, 7(3), 79; https://doi.org/10.3390/cryst7030079 - 06 Mar 2017
Cited by 22 | Viewed by 5896
Abstract
In this article, a ferroelectric liquid crystal (FLC) dammann grating (DG) is demonstrated based on the patterned photoalignment technology. By applying low electric field (10 V) on the FLC DG, the grating can switch between a diffractive state with 7 × 7 optical [...] Read more.
In this article, a ferroelectric liquid crystal (FLC) dammann grating (DG) is demonstrated based on the patterned photoalignment technology. By applying low electric field (10 V) on the FLC DG, the grating can switch between a diffractive state with 7 × 7 optical spots array and a non-diffractive state, depending on the polarity of electric field. The FLC DG shows very fast switching speed with switching on time and off time to be only 81 μs and 59 μs respectively. Comparing with other fast LC DGs such as the ones based on blue phase LC or dual-frequency LC, the switching speed of the proposed FLC DG is about one order faster, which provides great potential and perspective for the FLC DG to be applied in a broad range of optical applications such as optical communication and beam shaping. Full article
(This article belongs to the Special Issue Micro and Nano Patterned Substrates for Liquid Crystal Alignment)
Show Figures

Graphical abstract

985 KiB  
Article
Unexpected Au Alloying in Tailoring In-Doped SnTe Nanostructures with Gold Nanoparticles
by Samuel Atherton, Benjamin Steele and Satoshi Sasaki
Crystals 2017, 7(3), 78; https://doi.org/10.3390/cryst7030078 - 06 Mar 2017
Cited by 3 | Viewed by 4098
Abstract
Materials with strong spin-orbit interaction and superconductivity are candidates for topological superconductors that may host Majorana fermions (MFs) at the edges/surfaces/vortex cores. Bulk-superconducting carrier-doped topological crystalline insulator, indium-doped tin telluride (In-SnTe) is one of the promising materials. Robust superconductivity of In-SnTe nanostructures has [...] Read more.
Materials with strong spin-orbit interaction and superconductivity are candidates for topological superconductors that may host Majorana fermions (MFs) at the edges/surfaces/vortex cores. Bulk-superconducting carrier-doped topological crystalline insulator, indium-doped tin telluride (In-SnTe) is one of the promising materials. Robust superconductivity of In-SnTe nanostructures has been demonstrated recently. Intriguingly, not only 3-dimensional (3D) nanostructures but also ultra-thin quasi-2D and quasi-1D systems can be grown by the vapor transport method. In particular, nanostructures with a controlled dimension will give us a chance to understand the dimensionality and the quantum confinement effects on the superconductivity of the In-SnTe and may help us work on braiding MFs in various dimensional systems for future topological quantum computation technology. With this in mind, we employed gold nanoparticles (GNPs) with well-identified sizes to tailor In-SnTe nanostructures grown by vapor transport. However, we could not see clear evidence that the presence of the GNPs is necessary or sufficient to control the size of the nanostructures. Nevertheless, it should be noted that a weak correlation between the diameter of GNPs and the dimensions of the smallest nanostructures has been found so far. To our surprise, the ones grown under the vapor–liquid–solid mechanism, with the use of the GNPs, contained gold that is widely and inhomogeneously distributed over the whole body. Full article
(This article belongs to the Special Issue Topological Crystalline Insulators: Current Progress and Prospects)
Show Figures

Figure 1

2739 KiB  
Article
Synthesis, Crystal Structure and Catalytic Activity of a 1D Chained Ca(II) Coordination Polymer with 3,5-Bis(4-pyridylmethoxy)benzoate Ligand
by Li-Hua Wang, Xin Wang and Xi-Shi Tai
Crystals 2017, 7(3), 72; https://doi.org/10.3390/cryst7030072 - 06 Mar 2017
Cited by 9 | Viewed by 3770
Abstract
A new 1D chained Ca(II) coordination polymer—namely, [CaL2(H2O)2]n (HL = 3,5-bis(4-pyridylmethoxy)benzoic acid)—was synthesized though the reaction of Ca(ClO4)2·4H2O, 3,5-bis(4-pyridylmethoxy)benzoic acid and NaOH in H2O/CH3CH2OH [...] Read more.
A new 1D chained Ca(II) coordination polymer—namely, [CaL2(H2O)2]n (HL = 3,5-bis(4-pyridylmethoxy)benzoic acid)—was synthesized though the reaction of Ca(ClO4)2·4H2O, 3,5-bis(4-pyridylmethoxy)benzoic acid and NaOH in H2O/CH3CH2OH (v:v = 1:2) solution. Its structure was determined by elemental analysis, infrared spectrum, and single-crystal XRD. Structural analyses show that each Ca(II) ion is eight-coordinated by six oxygen atoms of four 3,5-bis(4-pyridylmethoxy)benzoate ligands and two oxygen atoms of two coordinated H2O molecules to form a square-antiprismatic CaO8 polyhedron. The Ca(II) complex displays a 1D chained structure constructed by the bridging effect of the bidentate carboxyl group of 3,5-bis(4-pyridylmethoxy)benzoate ligand. The catalytic activity of the Ca-complex was tested for the preparation of propargylamine in the A3 coupling reaction. Full article
(This article belongs to the Section Crystalline Materials)
Show Figures

Figure 1

5186 KiB  
Article
The Effect of Trimethylaluminum Flow Rate on the Structure and Optical Properties of AlInGaN Quaternary Epilayers
by Dongbo Wang, Gang Liu, Shujie Jiao, Lingping Kong, Teren Liu, Tong Liu, Jinzhong Wang, Fengyun Guo, Chunyang Luan and Zhenghao Li
Crystals 2017, 7(3), 69; https://doi.org/10.3390/cryst7030069 - 06 Mar 2017
Cited by 4 | Viewed by 4375
Abstract
In this work, a series of quaternary AlxInyGa1−x−yN thin films have been successfully achieved using metal organic chemical vapor deposition (MOCVD) method with adjustable trimethylaluminum (TMA) flows. Surface morphology and optical properties of AlxIny [...] Read more.
In this work, a series of quaternary AlxInyGa1−x−yN thin films have been successfully achieved using metal organic chemical vapor deposition (MOCVD) method with adjustable trimethylaluminum (TMA) flows. Surface morphology and optical properties of AlxInyGa1−x−yN films have been evaluated. The indium segregation effect on the enhancement of UV luminescence emission in AlxInyGa1-x-yN films with increasing TMA flows was investigated. Our results shed some lights on future optical materials design and LED/LD applications. Full article
(This article belongs to the Special Issue Crystal Growth for Optoelectronic and Piezoelectric Applications)
Show Figures

Figure 1

1647 KiB  
Article
A Reversible Single-Crystal to Single-Crystal Thermal Phase Transformation of 3-(2-Bromo-4-(1-methylethyl)phenyl)-1,1-dimethyl urea
by Benson M. Kariuki and Gamal A. El-Hiti
Crystals 2017, 7(3), 75; https://doi.org/10.3390/cryst7030075 - 04 Mar 2017
Cited by 2 | Viewed by 3954
Abstract
3-(2-Bromo-4-(1-methylethyl)phenyl)-1,1-dimethylurea was synthesized and structurally characterized at 296 K, 200 K and 140 K. A reversible thermal phase transformation was observed at ~170–180 K. On cooling, the structure transforms from a monoclinic to a triclinic crystal system. The isopropyl group is disordered above [...] Read more.
3-(2-Bromo-4-(1-methylethyl)phenyl)-1,1-dimethylurea was synthesized and structurally characterized at 296 K, 200 K and 140 K. A reversible thermal phase transformation was observed at ~170–180 K. On cooling, the structure transforms from a monoclinic to a triclinic crystal system. The isopropyl group is disordered above the phase transition temperature but is ordered below the transition temperature. Full article
Show Figures

Graphical abstract

4609 KiB  
Article
Numerical Study of the Thermal and Flow Fields during the Growth Process of 800 kg and 1600 kg Silicon Feedstock
by Thi Hoai Thu Nguyen, Jyh Chen Chen, Chieh Hu, Chun Hung Chen, Yen Hao Huang, Huang Wei Lin, Andy Yu, Bruce Hsu, Michael Yang and Ray Yang
Crystals 2017, 7(3), 74; https://doi.org/10.3390/cryst7030074 - 03 Mar 2017
Cited by 6 | Viewed by 4191
Abstract
Two-dimensional (2D) transient numerical simulations are performed to investigate the evolution of the thermal and flow fields during the growth of multi-crystalline silicon ingots with two different silicon feedstock capacities, 800 kg and 1600 kg. The simulation results show that there are differences [...] Read more.
Two-dimensional (2D) transient numerical simulations are performed to investigate the evolution of the thermal and flow fields during the growth of multi-crystalline silicon ingots with two different silicon feedstock capacities, 800 kg and 1600 kg. The simulation results show that there are differences in the structure of the melt flow. In the 1600 kg case, there is a reduction in the concavity of the crystal-melt interface near the crucible wall and an increase in the convexity of the interface at higher solidification fractions. Moreover, the Voronkov ratios, which are indicative of the formation of defects, become lower during the solidification process. Full article
(This article belongs to the Special Issue Global Modeling in Crystal Growth)
Show Figures

Figure 1

8604 KiB  
Article
Enhanced Thermoelectric Properties of Graphene/Cu2SnSe3 Composites
by Degang Zhao, Xuezhen Wang and Di Wu
Crystals 2017, 7(3), 71; https://doi.org/10.3390/cryst7030071 - 28 Feb 2017
Cited by 28 | Viewed by 5976
Abstract
Cu2SnSe3 material is regarded as a potential thermoelectric material due to its relatively high carrier mobility and low thermal conductivity. In this study, graphene was introduced into the Cu2SnSe3 powder by ball milling, and the bulk graphene/Cu [...] Read more.
Cu2SnSe3 material is regarded as a potential thermoelectric material due to its relatively high carrier mobility and low thermal conductivity. In this study, graphene was introduced into the Cu2SnSe3 powder by ball milling, and the bulk graphene/Cu2SnSe3 thermoelectric composites were prepared by spark plasma sintering. The graphene nanosheets distributed uniformly in the Cu2SnSe3 matrix. Meanwhile, some graphene nanosheets tended to form thick aggregations, and the average length of these aggregations was about 3 μm. With the fraction of graphene increasing, the electrical conductivity of graphene/Cu2SnSe3 samples increased greatly while the Seebeck coefficient was decreased. The introduction of graphene nanosheets can reduce the thermal conductivity effectively resulting from the phonon scattering by the graphene interface. When the content of graphene exceeds a certain value, the thermal conductivity of graphene/Cu2SnSe3 composites starts to increase. The achieved highest figure of merit (ZT) for 0.25 vol % graphene/Cu2SnSe3 composite was 0.44 at 700 K. Full article
(This article belongs to the Special Issue Materials Processing and Crystal Growth for Thermoelectrics)
Show Figures

Figure 1

4471 KiB  
Article
Effect of Diazotated Sulphonated Polystyrene Films on the Calcium Oxalate Crystallization
by Patricio Vásquez-Quitral, Javier Toledo Arana, Maria Cristina Miras, Diego Fernando Acevedo, Cesar Alfredo Barbero and Andrónico Neira-Carrillo
Crystals 2017, 7(3), 70; https://doi.org/10.3390/cryst7030070 - 28 Feb 2017
Cited by 5 | Viewed by 5491
Abstract
Pathological crystallization of calcium oxalate (CaOx) inside the urinary tract is called calculi or kidney stone (Urolithiasis). CaOx exhibits three crystalline types in nature: CaOx monohydrate COM, dihydrate COD and trihydrate COT. COD and COM are often found in urinary calculi, particularly COM. [...] Read more.
Pathological crystallization of calcium oxalate (CaOx) inside the urinary tract is called calculi or kidney stone (Urolithiasis). CaOx exhibits three crystalline types in nature: CaOx monohydrate COM, dihydrate COD and trihydrate COT. COD and COM are often found in urinary calculi, particularly COM. Langmuir monolayers, membrane vesicles, phospholipids’ micelles, among others, have been adopted as simplified biomimetic template-models to study in vitro the urolithiasis through CaOx. The nucleation and crystal growth of COM on self-assembled lipid monolayers have revealed that the negatively charged phosphatidylserine interface is a strong promoter of COM. Herein, we describe the synthesis and physicochemical characterization of diazotated sulphonated polystyrene films (DSPFs), prepared from various aminocompounds varying their polarity degree i.e., polar, non-polar and acidic DSPF derivatives. We also used these DSPFs as polymeric templates in crystallization experiments of CaOx in vitro. Images obtained by optical microscopy and scanning electron microscopy confirmed the precipitation of COM crystals on the DSPF surface. The employment of functionalized polymeric films as templates for CaOx crystallization represents a viable approach for understanding inorganic mineralization. Full article
(This article belongs to the Special Issue Membrane-Assisted Crystallization)
Show Figures

Figure 1

8410 KiB  
Article
Structures, Photophysical Properties, and Growth Patterns of Methylurea Coordinated Ni(II) and Mn(II) Complexes
by Wenting Wang, Zhihuang Xu, Liwang Ye, Genbo Su and Xinxin Zhuang
Crystals 2017, 7(3), 68; https://doi.org/10.3390/cryst7030068 - 28 Feb 2017
Cited by 2 | Viewed by 6012
Abstract
Four coordinated complexes MnxNi(1−x)(C2H6N2O)6SO4 (x=0, 0.33, 0.75, 0.90) were synthesized and characterized. Single-crystal X-ray analysis revealed that the complexes belong to the trigonal crystal family, R-3c space group. Spiral and [...] Read more.
Four coordinated complexes MnxNi(1−x)(C2H6N2O)6SO4 (x=0, 0.33, 0.75, 0.90) were synthesized and characterized. Single-crystal X-ray analysis revealed that the complexes belong to the trigonal crystal family, R-3c space group. Spiral and terraced nucleus growth modes were observed by atomic force microscopy (AFM) in the crystals. Thermogravimetric analysis (TGA) and differential thermal analysis (DTA) measurements showed their excellent thermostability until 200 °C. UV–vis spectra revealed that the transmission peaks of these crystals have a slight bathochromic shift compared to nickel sulfate hexahydrate (NSH), and the transmittance in the UV range increased as the proportion of Mn2+ increased. With their photophysical properties remaining similar, the much higher heat endurance is rendering these crystals better suitable for UV light filter (ULF) applications. Full article
Show Figures

Graphical abstract

3259 KiB  
Article
Single Crystal Growth of Multiferroic Double Perovskites: Yb2CoMnO6 and Lu2CoMnO6
by Hwan Young Choi, Jae Young Moon, Jong Hyuk Kim, Young Jai Choi and Nara Lee
Crystals 2017, 7(3), 67; https://doi.org/10.3390/cryst7030067 - 27 Feb 2017
Cited by 18 | Viewed by 6961
Abstract
We report on the growth of multiferroic Yb2CoMnO6 and Lu2CoMnO6 single crystals which were synthesized by the flux method with Bi2O3. Yb2CoMnO6 and Lu2CoMnO6 crystallize in a [...] Read more.
We report on the growth of multiferroic Yb2CoMnO6 and Lu2CoMnO6 single crystals which were synthesized by the flux method with Bi2O3. Yb2CoMnO6 and Lu2CoMnO6 crystallize in a double-perovskite structure with a monoclinic P21/n space group. Bulk magnetization measurements of both specimens revealed strong magnetic anisotropy and metamagnetic transitions. We observed a dielectric anomaly perpendicular to the c axis. The strongly coupled magnetic and dielectric states resulted in the variation of both the dielectric constant and the magnetization by applying magnetic fields, offering an efficient approach to accomplish intrinsically coupled functionality in multiferroics. Full article
(This article belongs to the Special Issue Multiferroics Crystals)
Show Figures

Figure 1

3466 KiB  
Article
Ni-Co Alloy and Multisegmented Ni/Co Nanowire Arrays Modulated in Composition: Structural Characterization and Magnetic Properties
by Miguel Méndez, Silvia González, Víctor Vega, Jose M. Teixeira, Blanca Hernando, Carlos Luna and Víctor M. Prida
Crystals 2017, 7(3), 66; https://doi.org/10.3390/cryst7030066 - 26 Feb 2017
Cited by 38 | Viewed by 7239
Abstract
Design of novel multisegmented magnetic nanowires can pave the way for the next generation of data storage media and logical devices, magnonic crystals, or in magneto-plasmonics, among other energy conversion, recovery, and storage technological applications. In this work, we present a detailed study [...] Read more.
Design of novel multisegmented magnetic nanowires can pave the way for the next generation of data storage media and logical devices, magnonic crystals, or in magneto-plasmonics, among other energy conversion, recovery, and storage technological applications. In this work, we present a detailed study on the synthesis, morphology, structural, and magnetic properties of Ni, Co, and Ni-Co alloy and multisegmented Ni/Co nanowires modulated in composition, which were grown by template-assisted electrodeposition employing nanoporous anodic aluminum oxide as patterned templates. X-ray diffraction, and scanning and high-resolution transmission electron microscopies allowed for the structural, morphological, and compositional investigations of a few micrometers long and approximately 40 nm in diameter of pure Ni and Co single elements, together with multisegmented Ni/Co and alloyed Ni-Co nanowires. The vibrating sample magnetometry technique enabled us to extract the main characteristic magnetic parameters for these samples, thereby evaluating their different anisotropic magnetic behaviors and discuss them based on their morphological and structural features. These novel functional magnetic nanomaterials can serve as potential candidates for multibit magnetic systems in ultra-high-density magnetic data storage applications. Full article
(This article belongs to the Special Issue Advance in Crystalline Thin Wires)
Show Figures

Graphical abstract

5274 KiB  
Article
A 130 GHz Electro-Optic Ring Modulator with Double-Layer Graphene
by Lei Wu, Hongxia Liu, Jiabin Li, Shulong Wang, Sheng Qu and Lu Dong
Crystals 2017, 7(3), 65; https://doi.org/10.3390/cryst7030065 - 26 Feb 2017
Cited by 13 | Viewed by 8044
Abstract
The optical absorption coefficient of graphene will change after injecting carriers. Based on this principle, a high-speed double-layer graphene electro-optic modulator with a ring resonator structure was designed in this paper. From the numerical simulations, we designed a modulator. Its optical bandwidth is [...] Read more.
The optical absorption coefficient of graphene will change after injecting carriers. Based on this principle, a high-speed double-layer graphene electro-optic modulator with a ring resonator structure was designed in this paper. From the numerical simulations, we designed a modulator. Its optical bandwidth is larger than 130 GHz, the switching energy is 0.358 fJ per bit, and the driven voltage is less than 1.2 V. At the same time, the footprint of the proposed modulator is less than 10 microns squared, which makes the process compatible with the Complementary Metal Oxide Semiconductors (CMOS) process. This will provide the possibility for the on-chip integration of the photoelectric device. Full article
Show Figures

Graphical abstract

229 KiB  
Editorial
Quo Vadis Quasicrystals?
by Enrique Maciá Barber
Crystals 2017, 7(3), 64; https://doi.org/10.3390/cryst7030064 - 24 Feb 2017
Cited by 3 | Viewed by 4209
Abstract
This Special Issue aims at gaining a deeper understanding on the relationship between the underlying structural order and the resulting physical properties in aperiodic systems, including quasicrystalline and related complex metallic alloys, photonic quasicrystals, and other structures exhibiting long-range aperiodic order. This Special [...] Read more.
This Special Issue aims at gaining a deeper understanding on the relationship between the underlying structural order and the resulting physical properties in aperiodic systems, including quasicrystalline and related complex metallic alloys, photonic quasicrystals, and other structures exhibiting long-range aperiodic order. This Special Issue contains 12 papers which highlight recent developments in quasiperiodic crystal structure, photonic quasicrystals and related optical devices, the intrinsic electrical, thermal, and mechanical properties of icosahedral and decagonal metallic alloys, and the nature of chemical bonding in intermetallic compounds, from a multidisciplinary perspective. In light of the results presented in the contributions collected in this Special Issue, we can confidently expect that new insights into the interdisciplinary science of quasicrystals will be gained in the years to come, providing a sharper picture of their structures and related physical properties, and spurring further progress in practical issues related to both materials engineering science and nanotechnology. Full article
(This article belongs to the Special Issue Structure and Properties of Quasicrystals 2016)
8281 KiB  
Review
Novel Dilute Bismide, Epitaxy, Physical Properties and Device Application
by Lijuan Wang, Liyao Zhang, Li Yue, Dan Liang, Xiren Chen, Yaoyao Li, Pengfei Lu, Jun Shao and Shumin Wang
Crystals 2017, 7(3), 63; https://doi.org/10.3390/cryst7030063 - 24 Feb 2017
Cited by 71 | Viewed by 9088
Abstract
Dilute bismide in which a small amount of bismuth is incorporated to host III-Vs is the least studied III-V compound semiconductor and has received steadily increasing attention since 2000. In this paper, we review theoretical predictions of physical properties of bismide alloys, epitaxial [...] Read more.
Dilute bismide in which a small amount of bismuth is incorporated to host III-Vs is the least studied III-V compound semiconductor and has received steadily increasing attention since 2000. In this paper, we review theoretical predictions of physical properties of bismide alloys, epitaxial growth of bismide thin films and nanostructures, surface, structural, electric, transport and optic properties of various binaries and bismide alloys, and device applications. Full article
Show Figures

Figure 1

Previous Issue
Next Issue
Back to TopTop