Materials

999 KiB

Open AccessReview

Role of Alloying Additions in Glass Formation and Properties of Bulk Metallic Glasses

by Na Chen, Laura Martin, Dmitri V. Luzguine-Luzgin and Akihisa Inoue

Materials 2010, 3(12), 5320-5339; https://doi.org/10.3390/ma3125320 - 21 Dec 2010

Cited by 59 | Viewed by 10636

Alloying addition, as a means of improving mechanical properties and saving on costs of materials, has been applied to a broad range of uses and products in the metallurgical fields. In the field of bulk metallic glasses (BMGs), alloying additions have also proven [...] Read more.

Alloying addition, as a means of improving mechanical properties and saving on costs of materials, has been applied to a broad range of uses and products in the metallurgical fields. In the field of bulk metallic glasses (BMGs), alloying additions have also proven to play effective and important roles in promoting glass formation, enhancing thermal stability and improving plasticity of the materials. Here, we review the work on the role of alloying additions in glass formation and performance improvement of BMGs, with focus on our recent results of alloying additions in Pd-based BMGs. Full article

(This article belongs to the Special Issue Amorphous Alloys)

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217 KiB

Open AccessArticle

Evaluation of Compatibility between Beetle-Killed Lodgepole Pine (Pinus Contorta var. Latifolia) Wood with Portland Cement

by Sorin A. Pasca, Ian D. Hartley, Matthew E. Reid and Ronald W. Thring

Materials 2010, 3(12), 5311-5319; https://doi.org/10.3390/ma3125311 - 17 Dec 2010

Cited by 18 | Viewed by 7964

Abstract

The compatibility of wood from mountain pine beetle (Dendroctonus ponderosa) killed lodgepole pine (Pinus contorta var. latifolia) with Portland cement was investigated based on time-since-death as a quantitative estimator, and the presence of blue-stained sapwood, brown rot, or white rot as qualitative indicators. [...] Read more.

The compatibility of wood from mountain pine beetle (Dendroctonus ponderosa) killed lodgepole pine (Pinus contorta var. latifolia) with Portland cement was investigated based on time-since-death as a quantitative estimator, and the presence of blue-stained sapwood, brown rot, or white rot as qualitative indicators. The exothermic behavior of cement hydration, maximum heat rate, time to reach this maximum, and total heat released within a 3.5–24 h interval were used for defining a new wood-cement compatibility index (CX). CX was developed and accounted for large discrepancies in assessing wood-cement compatibility compared to the previous methods. Using CX, no significant differences were found between fresh or beetle-killed wood with respect to the suitability for cement; except for the white rot samples which reached or exceeded the levels of incompatibility. An outstanding physicochemical behavior was also found for blue-stained sapwood and cement, producing significantly higher compatibility indices. Full article

(This article belongs to the Special Issue Innovative Materials in Civil Constructions)

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464 KiB

Open AccessReview

Membrane and Films Based on Novel Crown-Containing Dyes as Promising Chemosensoring Materials

by Sergei Yu. Zaitsev, Daria O. Solovieva and Ilia S. Zaitsev

Materials 2010, 3(12), 5293-5310; https://doi.org/10.3390/ma3125293 - 17 Dec 2010

Cited by 3 | Viewed by 7871

Abstract

This paper discusses several works on supramolecular systems such as monolayer and multilayer, polymer films of various crown-containing dyes, surface-active monomers and polymers. Design, production and investigation of the membrane nanostructures based on crown ethers is a rapidly developing field at the “junction” [...] Read more.

This paper discusses several works on supramolecular systems such as monolayer and multilayer, polymer films of various crown-containing dyes, surface-active monomers and polymers. Design, production and investigation of the membrane nanostructures based on crown ethers is a rapidly developing field at the “junction” of materials sciences and nanotechnology. These nanostructures can serve as convenient models for studying the self-organization and molecular recognition processes at interfaces that are typical for biomembranes. Based on the results obtained for such structures by absorption and fluorescence spectroscopy, atomic force and Brewster-angle microscopy, surface pressure and surface potential isotherm measurements, the possibility of developing micro- and nanomaterials possessing a set of specified properties (including chemosensor, photochromic and photorefractive materials) is demonstrated. Full article

(This article belongs to the Special Issue Advances in Dyes and Pigments)

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374 KiB

Open AccessArticle

Fabrication of Large Area Fishnet Optical Metamaterial Structures Operational at Near-IR Wavelengths

by Neilanjan Dutta, Iftekhar O. Mirza, Shouyuan Shi and Dennis W. Prather

Materials 2010, 3(12), 5283-5292; https://doi.org/10.3390/ma3125283 - 15 Dec 2010

Cited by 13 | Viewed by 9499

Abstract

In this paper, we demonstrate a fabrication process for large area (2 mm × 2 mm) fishnet metamaterial structures for near IR wavelengths. This process involves: (a) defining a sacrificial Si template structure onto a quartz wafer using deep-UV lithography and a dry [...] Read more.

In this paper, we demonstrate a fabrication process for large area (2 mm × 2 mm) fishnet metamaterial structures for near IR wavelengths. This process involves: (a) defining a sacrificial Si template structure onto a quartz wafer using deep-UV lithography and a dry etching process (b) deposition of a stack of Au-SiO₂-Au layers and (c) a ‘lift-off’ process which removes the sacrificial template structure to yield the fishnet structure. The fabrication steps in this process are compatible with today’s CMOS technology making it eminently well suited for batch fabrication. Also, depending on area of the exposure mask available for patterning the template structure, this fabrication process can potentially lead to optical metamaterials spanning across wafer-size areas. Full article

(This article belongs to the Special Issue Next Wave of Metamaterials)

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616 KiB

Open AccessArticle

Chemistry of the Fe₂O₃/BiFeO₃ Interface in BiFeO₃ Thin Film Heterostructures

by Miryam Arredondo, Quentin M. Ramasse, Kashinath Bogle and Valanoor Nagarajan

Materials 2010, 3(12), 5274-5282; https://doi.org/10.3390/ma3125274 - 14 Dec 2010

Cited by 7 | Viewed by 9561

Abstract

We investigate the interfacial chemistry of secondary Fe₂O₃ phases formed in a BiFeO₃ (BFO) layer in BFO/ La_0.67Sr_0.33MnO₃ (LSMO)/SrTiO₃ (STO) heterostructures. A combination of high-resolution spherical aberration corrected scanning TEM and spectroscopy results, [...] Read more.

We investigate the interfacial chemistry of secondary Fe₂O₃ phases formed in a BiFeO₃ (BFO) layer in BFO/ La_0.67Sr_0.33MnO₃ (LSMO)/SrTiO₃ (STO) heterostructures. A combination of high-resolution spherical aberration corrected scanning TEM and spectroscopy results, reveals that specific chemical and crystallographic similarities between Fe₂O₃ and BFO, enable the BFO layer to form a facile host for Fe₂O₃. Full article

(This article belongs to the Special Issue Advances in Ferroelectric & Piezoelectric Materials)

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773 KiB

Open AccessArticle

Structure Analyses of Fe-based Metallic Glasses by Electron Diffraction

by Akihiko Hirata and Yoshihiko Hirotsu

Materials 2010, 3(12), 5263-5273; https://doi.org/10.3390/ma3125263 - 13 Dec 2010

Cited by 13 | Viewed by 8140

Abstract

Nanoscale structural information of amorphous structures has become obtainable by using nanobeam electron diffraction in combination with high resolution imaging. In addition, accurate radial distribution function analysis using energy filter has also become available to know averaged amorphous structures. In this paper, we [...] Read more.

Nanoscale structural information of amorphous structures has become obtainable by using nanobeam electron diffraction in combination with high resolution imaging. In addition, accurate radial distribution function analysis using energy filter has also become available to know averaged amorphous structures. In this paper, we introduce some applications of these techniques, especially to several Fe-based metallic glasses. On the basis of these results, we discuss a relationship between the glass structure and the glass stability in Fe-based metallic glasses Full article

(This article belongs to the Special Issue Amorphous Alloys)

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920 KiB

Open AccessReview

Bond Strength—Coordination Number Fluctuation Model of Viscosity: An Alternative Model for the Vogel-Fulcher-Tammann Equation and an Application to Bulk Metallic Glass Forming Liquids

by Masahiro Ikeda and Masaru Aniya

Materials 2010, 3(12), 5246-5262; https://doi.org/10.3390/ma3125246 - 10 Dec 2010

Cited by 42 | Viewed by 11791

Abstract

The Vogel-Fulcher-Tammann (VFT) equation has been used extensively in the analysis of the experimental data of temperature dependence of the viscosity or of the relaxation time in various types of supercooled liquids including metallic glass forming materials. In this article, it is shown [...] Read more.

The Vogel-Fulcher-Tammann (VFT) equation has been used extensively in the analysis of the experimental data of temperature dependence of the viscosity or of the relaxation time in various types of supercooled liquids including metallic glass forming materials. In this article, it is shown that our model of viscosity, the Bond Strength—Coordination Number Fluctuation (BSCNF) model, can be used as an alternative model for the VFT equation. Using the BSCNF model, it was found that when the normalized bond strength and coordination number fluctuations of the structural units are equal, the viscosity behaviors described by both become identical. From this finding, an analytical expression that connects the parameters of the BSCNF model to the ideal glass transition temperature T₀ of the VFT equation is obtained. The physical picture of the Kohlrausch-Williams-Watts relaxation function in the glass forming liquids is also discussed in terms of the cooperativity of the structural units that form the melt. An example of the application of the model is shown for metallic glass forming liquids. Full article

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526 KiB

Open AccessReview

Piezoelectric Materials Synthesized by the Hydrothermal Method and Their Applications

by Takeshi Morita

Materials 2010, 3(12), 5236-5245; https://doi.org/10.3390/ma3125236 - 9 Dec 2010

Cited by 34 | Viewed by 12225

Abstract

Synthesis by the hydrothermal method has various advantages, including low reaction temperature, three-dimensional substrate availability, and automatic polarization alignment during the process. In this review, powder synthesis, the fabrication of piezoelectric thin films, and their applications are introduced. A polycrystalline lead zirconate titanate [...] Read more.

Synthesis by the hydrothermal method has various advantages, including low reaction temperature, three-dimensional substrate availability, and automatic polarization alignment during the process. In this review, powder synthesis, the fabrication of piezoelectric thin films, and their applications are introduced. A polycrystalline lead zirconate titanate (PZT) thin film was applied to a micro ultrasonic motor, and an epitaxial lead titanate (PbTiO₃) thin film was estimated as a ferroelectric data storage medium. Ferroelectric and piezoelectric properties were successfully obtained for epitaxial PbTiO₃ films. As lead-free piezoelectric powders, KNbO₃ and NaNbO₃ powders were synthesized by the hydrothermal method and sintered together to form (K,Na)NbO₃ ceramics, from which reasonable piezoelectric performance was achieved. Full article

(This article belongs to the Special Issue Advances in Ferroelectric & Piezoelectric Materials)

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655 KiB

Open AccessReview

Morphologies, Preparations and Applications of Layered Double Hydroxide Micro-/Nanostructures

by Ye Kuang, Lina Zhao, Shuai Zhang, Fazhi Zhang, Mingdong Dong and Sailong Xu

Materials 2010, 3(12), 5220-5235; https://doi.org/10.3390/ma3125220 - 9 Dec 2010

Cited by 140 | Viewed by 19378

Abstract

Layered double hydroxides (LDHs), also well-known as hydrotalcite-like layered clays, have been widely investigated in the fields of catalysts and catalyst support, anion exchanger, electrical and optical functional materials, flame retardants and nanoadditives. This feature article focuses on the progress in micro-/nanostructured LDHs [...] Read more.

Layered double hydroxides (LDHs), also well-known as hydrotalcite-like layered clays, have been widely investigated in the fields of catalysts and catalyst support, anion exchanger, electrical and optical functional materials, flame retardants and nanoadditives. This feature article focuses on the progress in micro-/nanostructured LDHs in terms of morphology, and also on the preparations, applications, and perspectives of the LDHs with different morphologies. Full article

(This article belongs to the Special Issue Nanomaterials)

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319 KiB

Open AccessArticle

Positive and Negative Temperature Dependence in the Resistivity of Crystallized Zr-Fe-Ni Metallic Glasses

by Fathalla Hamed

Materials 2010, 3(12), 5212-5219; https://doi.org/10.3390/ma3125212 - 7 Dec 2010

Cited by 4 | Viewed by 8875

Abstract

Ni_0.25Fe_0.75Zr₃ metallic glassy ribbons were annealed in evacuated quartz ampoules beyond the crystallization temperatures (T_x ~655 K) over the range 773 to 1,173 K for varying periods of time. The resistivity of samples annealed over the temperature [...] Read more.

Ni_0.25Fe_0.75Zr₃ metallic glassy ribbons were annealed in evacuated quartz ampoules beyond the crystallization temperatures (T_x ~655 K) over the range 773 to 1,173 K for varying periods of time. The resistivity of samples annealed over the temperature range 923 to 1,073 K for periods less than four hours increased as a function of decreasing temperature, while it decreased for samples annealed for more than four hours or at temperatures below 923 K or above 1,073 K for any period of time. All the annealed samples were found to contain only Ni, Fe and Zr from energy dispersive X-ray (EDX) analyses. Full article

(This article belongs to the Special Issue Amorphous Alloys)

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1871 KiB

Open AccessArticle

In vitro Evaluation of Acyclovir/Chitosan Floating Systems

by Roberto Ruiz-Caro and María D. Veiga

Materials 2010, 3(12), 5195-5211; https://doi.org/10.3390/ma3125195 - 6 Dec 2010

Cited by 8 | Viewed by 8855

Abstract

Chitosan (CS) floating lyophilized formulations (L) for gastric drug delivery of acyclovir (ACV) have been developed. The freeze-dried formulations were obtained from acidic aqueous suspensions prepared with different ACV/CS ratios. No changes in ACV crystallinity were observed during X-ray diffraction powder studies as [...] Read more.

Chitosan (CS) floating lyophilized formulations (L) for gastric drug delivery of acyclovir (ACV) have been developed. The freeze-dried formulations were obtained from acidic aqueous suspensions prepared with different ACV/CS ratios. No changes in ACV crystallinity were observed during X-ray diffraction powder studies as a consequence of the manufacturing process. Considering that fed and fasted states modified the intragastric pH, swelling and in vitro dissolution studies were carried out in different acidic media (0.1 M HCl and progressive pH medium) in order to understand the influence of these physiological states on ACV/CS formulations. Swelling behavior of the floating lyophilized formulations was dependent on CS and ACV proportions within L and on medium nature due to pH dependent CS solubility. Furthermore, no interactions between ACV and CS were detected in solid state according to the X-ray studies. In vitro dissolution of ACV from L was influenced by the swelling behavior. However, it is feasible to optimize the ACV/CS ratios to achieve a desired formulation that releases the total quantity of ACV at a specific time. Moreover, floatability was assessed by buoyancy tests. The results demonstrated that the freeze-drying process achieved effective floating systems capable of remaining within the stomach while the total amount of ACV is released from L. Full article

(This article belongs to the Special Issue Chitins)

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745 KiB

Open AccessReview

Applications of Piezoelectric Materials in Structural Health Monitoring and Repair: Selected Research Examples

by Wen Hui Duan, Quan Wang and Ser Tong Quek

Materials 2010, 3(12), 5169-5194; https://doi.org/10.3390/ma3125169 - 6 Dec 2010

Cited by 113 | Viewed by 14346

Abstract

The paper reviews the recent applications of piezoelectric materials in structural health monitoring and repair conducted by the authors. First, commonly used piezoelectric materials in structural health monitoring and structure repair are introduced. The analysis of plain piezoelectric sensors and actuators and interdigital [...] Read more.

The paper reviews the recent applications of piezoelectric materials in structural health monitoring and repair conducted by the authors. First, commonly used piezoelectric materials in structural health monitoring and structure repair are introduced. The analysis of plain piezoelectric sensors and actuators and interdigital transducer and their applications in beam, plate and pipe structures for damage detection are reviewed in detail. Second, an overview is presented on the recent advances in the applications of piezoelectric materials in structural repair. In addition, the basic principle and the current development of the technique are examined. Full article

(This article belongs to the Special Issue Advances in Ferroelectric & Piezoelectric Materials)

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402 KiB

Open AccessReview

Thermotropic and Thermochromic Polymer Based Materials for Adaptive Solar Control

by Arno Seeboth, Ralf Ruhmann and Olaf Mühling

Materials 2010, 3(12), 5143-5168; https://doi.org/10.3390/ma3125143 - 6 Dec 2010

Cited by 175 | Viewed by 23047

Abstract

The aim of this review is to present the actual status of development in adaptive solar control by use of thermotropic and organic thermochromic materials. Such materials are suitable for application in smart windows. In detail polymer blends, hydrogels, resins, and thermoplastic films [...] Read more.

The aim of this review is to present the actual status of development in adaptive solar control by use of thermotropic and organic thermochromic materials. Such materials are suitable for application in smart windows. In detail polymer blends, hydrogels, resins, and thermoplastic films with a reversible temperature-dependent switching behavior are described. A comparative evaluation of the concepts for these energy efficient materials is given as well. Furthermore, the change of strategy from ordinary shadow systems to intrinsic solar energy reflection materials based on phase transition components and a first remark about their realization is reported. Own current results concerning extruded films and high thermally stable casting resins with thermotropic properties make a significant contribution to this field. Full article

(This article belongs to the Special Issue Solar Energy Materials)

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268 KiB

Open AccessReview

Dyes as Photoinitiators or Photosensitizers of Polymerization Reactions

by Jean-Pierre Fouassier, Fabrice Morlet-Savary, Jacques Lalevée, Xavier Allonas and Christian Ley

Materials 2010, 3(12), 5130-5142; https://doi.org/10.3390/ma3125130 - 2 Dec 2010

Cited by 122 | Viewed by 12147

Abstract

A short but up-to-date review on the role of dyes in the photoinitiation processes of polymerization reactions is presented. Radical and cationic reactions are largely encountered in the radiation curing and the imaging areas for use in traditional coating applications as well as [...] Read more.

A short but up-to-date review on the role of dyes in the photoinitiation processes of polymerization reactions is presented. Radical and cationic reactions are largely encountered in the radiation curing and the imaging areas for use in traditional coating applications as well as in high tech sectors such as nanofabrication, computer-to-plate processing, laser direct imaging, manufacture of optical elements, etc. Recent promising developments concerned with the introduction of the silyl radical chemistry that enhances the polymerization efficiency are also discussed. Full article

(This article belongs to the Special Issue Advances in Dyes and Pigments)

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1260 KiB

Open AccessArticle

Calcium Phosphate Bone Cements Including Sugar Surfactants: Part Two—Injectability, Adhesive Properties and Biocompatibility

by Ariane Bercier, Stéphane Gonçalves, Helène Autefage, Fabienne Briand-Mesange, Olivier Lignon and Juliette Fitremann

Materials 2010, 3(12), 5111-5129; https://doi.org/10.3390/ma3125111 - 2 Dec 2010

Cited by 8 | Viewed by 9426

Abstract

Addition of sugar surfactants, sucrose fatty acid esters and alkylpolyglucosides to a calcium phosphate cement, designed for bone reconstruction, is described. Thanks to their adsorption at the surface of the calcium phosphate particles, the sugar surfactants allowed a full injectability and brought a [...] Read more.

Addition of sugar surfactants, sucrose fatty acid esters and alkylpolyglucosides to a calcium phosphate cement, designed for bone reconstruction, is described. Thanks to their adsorption at the surface of the calcium phosphate particles, the sugar surfactants allowed a full injectability and brought a very good workability. Injectability was measured by monitoring force-distance curves. With some of the selected sugar surfactants adhesive properties of the cement pastes were also observed, which were measured by tack tests. Finally, some properties related to biological applications are described, including gentamicine release and osteoblast viability experiments. The whole study demonstrates that addition of these mild surfactants improved several properties of the calcium phosphate cement, without impairing function. Full article

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801 KiB

Open AccessReview

Control of Mechanical Properties of Thermoplastic Polyurethane Elastomers by Restriction of Crystallization of Soft Segment

by Ken Kojio, Mutsuhisa Furukawa, Yoshiteru Nonaka and Sadaharu Nakamura

Materials 2010, 3(12), 5097-5110; https://doi.org/10.3390/ma3125097 - 1 Dec 2010

Cited by 82 | Viewed by 12971

Abstract

Mechanical properties of thermoplastic polyurethane elastomers based on either polyether or polycarbonate (PC)-glycols, 4,4’-dipheylmethane diisocyanate (1,1’-methylenebis(4-isocyanatobenzene)), 1,4-butanediol, were controlled by restriction of crystallization of polymer glycols. For the polyether glycol based-polyurethane elastomers (PUEs), poly(oxytetramethylene) glycol (PTMG), and PTMG incorporating dimethyl groups (PTG-X) and [...] Read more.

Mechanical properties of thermoplastic polyurethane elastomers based on either polyether or polycarbonate (PC)-glycols, 4,4’-dipheylmethane diisocyanate (1,1’-methylenebis(4-isocyanatobenzene)), 1,4-butanediol, were controlled by restriction of crystallization of polymer glycols. For the polyether glycol based-polyurethane elastomers (PUEs), poly(oxytetramethylene) glycol (PTMG), and PTMG incorporating dimethyl groups (PTG-X) and methyl side groups (PTG-L) were employed as a polymer glycol. For the PC-glycol, the randomly copolymerized PC-glycols with hexamethylene (C₆) and tetramethylene (C₄) units between carbonate groups with various composition ratios (C₄/C₆ = 0/100, 50/50, 70/30 and 90/10) were employed. The degree of microphase separation and mechanical properties of both the PUEs were investigated using differential scanning calorimetry, dynamic viscoelastic property measurements and tensile testing. Mechanical properties could be controlled by changing the molar ratio of two different monomer components. Full article

(This article belongs to the Special Issue Thermoplastic Elastomers)

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682 KiB

Open AccessArticle

Volumetrical Characterization of Sheet Molding Compounds

by Alfredo Calvimontes, Karina Grundke and Anett Müller

Materials 2010, 3(12), 5083-5096; https://doi.org/10.3390/ma3125083 - 1 Dec 2010

Cited by 2 | Viewed by 7514

Abstract

For a comprehensive study of Sheet Molding Compound (SMC) surfaces, topographical data obtained by chromatic confocal imaging were submitted systematically for the development of a profile model to understand the formation of cavities on the surface. In order to qualify SMC surfaces and [...] Read more.

For a comprehensive study of Sheet Molding Compound (SMC) surfaces, topographical data obtained by chromatic confocal imaging were submitted systematically for the development of a profile model to understand the formation of cavities on the surface. In order to qualify SMC surfaces and to predict their coatability, a characterization of cavities is applied. To quantify the effect of surface modification treatments, a new parameter (Surface Relative Smooth) is presented, applied and probed. The parameter proposed can be used for any surface modification of any solid material. Full article

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9827 KiB

Open AccessReview

Mn-doped Ge and Si: A Review of the Experimental Status

by Shengqiang Zhou and Heidemarie Schmidt

Materials 2010, 3(12), 5054-5082; https://doi.org/10.3390/ma3125054 - 26 Nov 2010

Cited by 31 | Viewed by 10420

Abstract

Diluted ferromagnetic semiconductors (FMS) are in the focus of intense research due to their potential applications in spintronics and their striking new physical properties. So far Mn-doped III-V compound semiconductors such as GaMnAs are the most important and best understood ones, but they [...] Read more.

Diluted ferromagnetic semiconductors (FMS) are in the focus of intense research due to their potential applications in spintronics and their striking new physical properties. So far Mn-doped III-V compound semiconductors such as GaMnAs are the most important and best understood ones, but they are ferromagnetic only at well below room temperature. An interesting alternative could be magnetic semiconductors based on elemental semiconductors, also owing to their compatibility with Si microelectronics. In the last decades, considerable amount of work has been devoted to fabricate Mn-doped Ge and Si FMS. In this article, the structural, magnetic and magneto-transport properties of Mn-doped Ge and Si will be reviewed. Full article

(This article belongs to the Special Issue Ferromagnetic Semiconductors)

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2058 KiB

Open AccessReview

Application of Nanostructures in Electrochromic Materials and Devices: Recent Progress

by Jin Min Wang, Xiao Wei Sun and Zhihui Jiao

Materials 2010, 3(12), 5029-5053; https://doi.org/10.3390/ma3125029 - 26 Nov 2010

Cited by 103 | Viewed by 15702

Abstract

The recent progress in application of nanostructures in electrochromic materials and devices is reviewed. ZnO nanowire array modified by viologen and WO₃, crystalline WO₃ nanoparticles and nanorods, mesoporous WO₃ and TiO₂, poly(3,4-ethylenedioxythiophene) nanotubes, Prussian blue nanoinks and [...] Read more.

The recent progress in application of nanostructures in electrochromic materials and devices is reviewed. ZnO nanowire array modified by viologen and WO₃, crystalline WO₃ nanoparticles and nanorods, mesoporous WO₃ and TiO₂, poly(3,4-ethylenedioxythiophene) nanotubes, Prussian blue nanoinks and nanostructures in switchable mirrors are reviewed. The electrochromic properties were significantly enhanced by applying nanostructures, resulting in faster switching responses, higher stability and higher optical contrast. A perspective on the development trends in electrochromic materials and devices is also proposed. Full article

(This article belongs to the Special Issue Solar Energy Materials)

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554 KiB

Open AccessArticle

Probing the Nanodomain Origin and Phase Transition Mechanisms in (Un)Poled PMN-PT Single Crystals and Textured Ceramics

by Aneta Slodczyk and Philippe Colomban

Materials 2010, 3(12), 5007-5028; https://doi.org/10.3390/ma3125007 - 25 Nov 2010

Cited by 63 | Viewed by 11810

Abstract

Outstanding electrical properties of solids are often due to the composition heterogeneity and/or the competition between two or more sublattices. This is true for superionic and superprotonic conductors and supraconductors, as well as for many ferroelectric materials. As in PLZT ferroelectric materials, the [...] Read more.

Outstanding electrical properties of solids are often due to the composition heterogeneity and/or the competition between two or more sublattices. This is true for superionic and superprotonic conductors and supraconductors, as well as for many ferroelectric materials. As in PLZT ferroelectric materials, the exceptional ferro- and piezoelectric properties of the PMN-PT ((1−x)PbMg_1/3Nb_2/3O₃−xPbTiO₃) solid solutions arise from the coexistence of different symmetries with long and short scales in the morphotropic phase boundary (MPB) region. This complex physical behavior requires the use of experimental techniques able to probe the local structure at the nanoregion scale. Since both Raman signature and thermal expansion behavior depend on the chemical bond anharmonicity, these techniques are very efficient to detect and then to analyze the subtitle structural modifications with an efficiency comparable to neutron scattering. Using the example of poled (field cooling or room temperature) and unpoled PMN-PT single crystal and textured ceramic, we show how the competition between the different sublattices with competing degrees of freedom, namely the Pb-Pb dominated by the Coulombian interactions and those built of covalent bonded entities (NbO₆ and TiO₆), determine the short range arrangement and the outstanding ferro- and piezoelectric properties. Full article

(This article belongs to the Special Issue Advances in Ferroelectric & Piezoelectric Materials)

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Materials, Volume 3, Issue 12 (December 2010) – 20 articles , Pages 5007-5339

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