bluuebunny/crossref_metadata_2025_split huggingface dataset:
Magnetic Domain Walls in Nanowires
Authors: Allenspach Rolf , Jubert Pierre-Olivier 
Published: February 2011

AbstractFor many decades, it was assumed that the characteristics of magnetic domain walls were determined by material properties and the walls were moved by magnetic fields.In the past few years, it has been shown that domain walls behave differently on the nanometer scale.Domain walls in small elements exhibit complex spin arrangements that strongly deviate from the wall types commonly encountered in magnetic thin-film systems, and they can be modified by changing the geometry of the element.Domain walls in nanowires can also be moved by injecting electrical current pulses.Whereas wall propagation is qualitatively explained by a spin transfer from the conduction electrons to the spins of the domain wall, important aspects of the observations cannot be explained by present models.Examples include the observation of a drastic transformation of the wall structure upon current injection and domain wall velocities that tend to be orders of magnitude smaller than anticipated from theory.
A Perspective on Modeling Materials in Extreme Environments: Oxidation of Ultrahigh-Temperature Ceramics
Authors: Bongiorno Angelo , Först Clemens J. , Kalia Rajiv K. , Li Ju , Marschall Jochen , Nakano Aiichiro , Opeka Mark M. , Talmy Inna G. , Vashishta Priya , Yip Sidney 
Published: February 2011

AbstractThe broader context of this discussion, based on a workshop where materials technologists and computational scientists engaged in a dialogue, is an awareness that modeling and simulation techniques and computational capabilities may have matured sufficiently to provide heretofore unavailable insights into the complex microstructural evolution of materials in extreme environments.As an example, this article examines the study of ultrahigh-temperature oxidation-resistant ceramics, through the combination of atomistic simulation and selected experiments.We describe a strategy to investigate oxygen transport through a multi-oxide scale—the protective layer of ultrahigh-temperature ceramic composites ZrB2-SiC and HfB2-SiC—by combining first-principles and atomistic modeling and simulation with selected experiments.
Low-Temperature Polycrystalline Silicon Thin-Film Transistors and Circuits on Flexible Substrates
Authors: van der Wilt P.C. , Kane M.G. , Limanov A.B. , Firester A.H. , Goodman L. , Lee J. , Abelson J.R. , Chitu A.M. , Im James S. 
Published: February 2011

AbstractLow-defect-density polycrystalline Si on flexible substrates can be instrumental in realizing the full potential of macroelectronics. Direct deposition or solid-phase crystallization techniques are often incompatible with polymers and produce materials with high defect densities. Excimer-laser annealing is capable of producing films of reasonable quality directly on polymer and metallic substrates. Sequential lateral solidification (SLS) is an advanced pulsed-laser-crystallization technique capable of producing Si films on polymers with lower defect density than can be obtained via excimer-laser annealing. Circuits built directly on polymers using these SLS films show the highest performance reported to date.
Theory of Nanocomposite Network Transistors for Macroelectronics Applications
Authors: Alam M.A. , Pimparkar N. , Kumar S. , Murthy J. 
Published: February 2011

AbstractA new class of nanocomposite network materials based on carbon nanotubes or silicon nanowires for thin-film transistors promises significant improvement in the performance of large-area electronics, or macroelectronics. Evaluation of this novel materials technology requires the development of device models. A multicomponent heterogeneous stick-percolation theory is used to show that the key features of this new transistor technology are the consequences of the percolating spatial geometry of the nanosticks (nanotubes, nanorods, or nanowires) that form the channel.
Biomaterials for Drug Delivery and Tissue Engineering
Authors: Langer Robert 
Published: February 2011

AbstractThe following article is an edited transcript based on the Von Hippel Award presentation by Robert Langer of the Massachusetts Institute of Technology on November 30, 2005, at the Materials Research Society Fall Meeting in Boston. Langer was honored with MRS's highest award for his “pioneering accomplishments in the science and application of biomaterials in drug delivery and tissue engineering, particularly in inventing the use of materials for protein and DNA delivery, and for his achievements in interdisciplinary research which have generated new medical products, created new fields of biomaterials science, and inspired research programs throughout the world.”
Isotopically Controlled Semiconductors
Authors: Haller Eugene E. 
Published: February 2011

The following article is an edited transcript based on the David Turnbull Lecture given by Eugene E. Haller (University of California, Berkeley) at the 2005 Materials Research Society Fall Meeting in Boston on November 29, 2005. The David Turnbull Lectureship is awarded to recognize the career of a scientist who has made outstanding contributions to understanding materials phenomena and properties through research, writing, and lecturing, as exemplified by the life work of David Turnbull. Haller was named the 2005 David Turnbull Lecturer for his “pioneering achievements and leadership in establishing the field of isotopically engineered semiconductors; for outstanding contributions to materials growth, doping and diffusion; and for excellence in lecturing, writing, and fostering international collaborations.”The scientific interest, increased availability, and technological promise of highly enriched isotopes have led to a sharp rise in the number of experimental and theoretical studies of isotopically controlled semiconductor crystals. This article reviews results obtained with isotopically controlled semiconductor bulk and thin–film heterostructures. Isotopic composition affects several properties, such as phonon energies, band structure, and lattice constant, in subtle, yet—for their physical understanding–significant ways. Large isotope-related effects are observed for thermal conductivity in local vibrational modes of impurities and after neutron transmutation doping. Spectacularly sharp photo-luminescence lines have been observed in ultrapure, isotopically enriched silicon crystals. Isotope multilayer structures are especially well suited for studies of simultaneous self-and dopant-diffusion. The absence of any chemical, mechanical, or electrical driving forces makes possible the study of an ideal random-walk problem, in which moving atoms go in random directions at random intervals. Isotopically controlled semiconductors may find applications in quantum computing, nanoscience, and spintronics.
Ultrafast Dynamics of Laser-Excited Solids
Authors: Reis D.A. , Gaffney K.J. , Gilmer G.H. , Torralva B. 
Published: February 2011

AbstractWe discuss recent experimental and theoretical results on ultrafast materials dynamics. Intense, femtosecond lasers can deposit energy in a time that is short compared with relaxation processes and can generate extremely large carrier densities that drive bond softening, nonthermal melting, and ablation. In particular, we present optical experiments on electronic softening of coherent phonons in bismuth and x-ray experiments on ultrafast disordering in indium antimonide that probe the bonding of the lattice under successively higher carrier concentrations. We review a number of molecular dynamics simulations and their assumptions, which address nonthermal melting. Large-scale molecular dynamics simulations elucidate the role of void formation in laser ablation.
Material Processing Using Femtosecond Lasers: Repairing Patterned Photomasks
Authors: Haight Richard , Longo Peter , Wagner Alfred 
Published: February 2011

AbstractThe use of ultrafast laser pulses is having an impact on materials processing in profound ways. “Machining” with femtosecond pulses affords considerable advantages over nanosecond pulses, such as subdiffraction-limited material ablation, where ablated spot dimensions are below that achievable when longer pulses are focused to the minimum spot size dictated by optical physics. These properties have been exploited to address what had become a critical problem in the semiconductor industry, the repair of patterned photomasks. We will describe how the fundamentals of femtosecond laser ablation have been implemented in a machine designed to repair photomasks. We will also describe experiments designed to deposit Cr metal onto fused-silica substrates using 100-fs, 400-nm light pulses at atmospheric pressure. Multiphoton dissociation of Cr(CO)6 adsorbed on fused-silica substrates initiates Cr deposition. The mechanisms for deposition on both transparent (fused silica) and absorbing (Cr metal) substrates are discussed. Finally, we describe experiments that were carried out to extend the photomask repair process to shorter wavelengths (below 200 nm) using light generated by frequency-mixing of ultrashort, 30-fs pulses in an Ar-filled capillary.
Dense Metal Membranes for the Production of High-Purity Hydrogen
Authors: Sholl David S. , Ma Y.H. 
Published: February 2011

AbstractDense metal membranes are a well-developed technology for the production of high-purity hydrogen. The physical mechanism of hydrogen transport across metal films—dissociation of molecular hydrogen, diffusion of interstitial atomic hydrogen, and subsequent recombinative desorption of molecular hydrogen—means that metal membranes can have extremely high selectivities for hydrogen transport relative to other gases. We describe current experimental and theoretical trends in the development of metal alloy membranes for hydrogen purification in practical, chemically robust processes.
The Application of Computational Modeling to Pharmaceutical Materials Science
Authors: Wassgren Carl , Curtis Jennifer Sinclair 
Published: February 2011

AbstractComputational modeling is a ubiquitous technique in materials science, but until recently this approach has not been widely applied to the drug development process. The formation of particles, their kinematics, and their response to processing stresses are increasingly being studied using computational techniques (computational fluid dynamics and discrete element analysis). These computational techniques can be predictive tools to guide scientists who are designing pharmaceutical dosage forms with specific macroscopic properties. This article gives an overview of the types of computational methods that are used in pharmaceutical materials science and provides examples of their application to some problems from the literature and the authors' own work.
Silicon-Based Microchemical Systems: Characteristics and Applications
Authors: Jensen Klavs F. 
Published: February 2011

AbstractMicrofabrication techniques and scale-up by replication promise to transform classical batch-wise chemical laboratory procedures into integrated systems capable of providing new understanding and control of fundamental processes. Such integrated microchemical systems would enable rapid, continuous discovery and development of new products with the use of fewer resources and the generation of less waste. Additional opportunities exist for on-demand and on-site synthesis, with perhaps the first applications emerging in portable energy sources based on the conversion of hydrocarbons to hydrogen for miniaturized fuel cells.Microchemical systems can be realized in a wide range of materials including stainless steel, glass, ceramics, silicon, and polymers. The high mechanical strength, excellent temperature characteristics, and good chemical compatibility of silicon combined with the existing fabrication infrastructure for microelectromechanical systems (MEMS) offer advantages in fabricating chemical microsystems that are compatible with strong solvents and operate at elevated temperatures and pressures. Furthermore, silicon-based microsensors for flow, pressure, and temperature can readily be integrated into the systems.Microsystems for broad chemical applications should be discovery tools that can easily be applied by chemists and materials scientists while also having a convincing “scale-out” to at least small production levels. The interplay of both these capabilities is important in making microreaction technology successful. Perhaps the largest impact of microchemical systems will ultimately be the ability to explore reaction conditions and chemistry at conditions that are otherwise difficult to establish in the laboratory. Case studies are selected to illustrate microfluidic applications in which silicon adds advantages, specifically, integration of physical sensors and infrared spectroscopy, highthroughput experimentation in moisture-sensitive organic synthesis, controlled synthesis of nanoparticles (quantum dots), multiphase and heterogeneous catalytic reactions at elevated temperatures and pressures, and thermal management in the conversion of hydrocarbons to hydrogen.
Recent Developments in Bulk Thermoelectric Materials
Authors: Nolas George S. , Poon Joe , Kanatzidis Mercouri 
Published: February 2011

AbstractGood thermoelectric materials possess low thermal conductivity while maximizing electric carrier transport. This article looks at various classes of materials to understand their behavior and determine methods to modify or “tune” them to optimize their thermoelectric properties. Whether it is the use of “rattlers” in cage structures such as skutterudites, or mixed-lattice atoms such as the complex half-Heusler alloys, the ability to manipulate the thermal conductivity of a material is essential in optimizing its properties for thermoelectric applications.
Materials for Multilayer Recording
Authors: Milster Tom D. , Zhang Yan 
Published: February 2011

AbstractAn attractive feature of optical discs is their capacity. Recent research has indicated that the capacity of optical discs can be increased by using multiple layers of bitwise data. Layers are spaced along the depth dimension of the discs. Individual layers are recorded and information is retrieved in a manner that is very similar to conventional optical disc systems using a single layer. The data capacity of each layer is nearly equal to the capacity of a single layer, thus increasing the capacity of a disc by a factor equal to the number of layers. In fact, dual-layer optical discs are already commercially available. With some storage materials, it is possible to record hundreds of data layers. However, system engineering trade-offs, like readout speed, are of concern. More conventional – materials can also be used for multilayer recording, but the number of layers is limited by the transmission properties of each layer. This article reviews the materials systems for multilayer recording, the interplay between materials properties and performance, and the optical systems used for multilayer recording.
Spin-Polarized Current in Spin Valves and Magnetic Tunnel Junctions
Authors: Parkin Stuart 
Published: February 2011

AbstractSpin-polarized currents can be generated by spin-dependent diffusive scattering in magnetic thin-film structures or by spin-dependent tunneling across ultrathin dielectrics sandwiched between magnetic electrodes.By manipulating the magnetic moments of the magnetic components of these spintronic materials, their resistance can be significantly changed, allowing the development of highly sensitive magnetic-field detectors or advanced magnetic memory storage elements.Whereas the magneto-resistance of useful devices based on spin-dependent diffusive scattering has hardly changed since its discovery nearly two decades ago, in the past five years there has been a remarkably rapid development in both the basic understanding of spin-dependent tunneling and the magnitude of useful tunnel magnetoresistance values.In particular, it is now evident that the magnitude of the spin polarization of tunneling currents in magnetic tunnel junctions not only is related to the spin-dependent electronic structure of the ferromagnetic electrodes but also is considerably influenced by the properties of the tunnel barrier and its interfaces with the magnetic electrodes.Whereas the maximum tunnel magnetoresistance of devices using amorphous alumina tunnel barriers and 3d transition-metal alloy ferromagnetic electrodes is about 70% at room temperature, using crystalline MgO tunnel barriers in otherwise the same structures gives tunnel magnetoresistance values of more than 350% at room temperature.
Nanometer-Scale Laser Direct-Write Using Near-Field Optics
Authors: Grigoropoulos Costas P. , Hwang David J. , Chimmalgi Anant 
Published: February 2011

AbstractThis article summarizes research on laser-based processing and structuring of materials at the nanoscale using optical near-field schemes. Both apertureless and tapered fiber near-field scanning optical microscope probes can deliver highly confined irradiation at sufficiently high intensities to cause morphological and structural changes in materials at the nanometer level. The energy emitted by the probes and the absorption within the target material are predicted by carrying out calculations of the near-field electromagnetic distribution. The effects of shrinking laser beam dimensions compete with the energy diffusion into the target material. Experimental results have shown well-controlled subtractive material modification with minimum feature size in the neighborhood of 10 nm. Precise patterning can be achieved via laser-assisted chemical etching. Control of the nucleation of nanostructures via rapid melting and crystallization is demonstrated. The article concludes with an outlook to applications.
The State of the Art and Future Prospects for Laser Direct-Write for Industrial and Commercial Applications
Authors: Sugioka Koji , Gu Bo , Holmes Andrew 
Published: February 2011

AbstractLaser direct-write (LDW) is an established technology for manufacturing electronic and optoelectronic appliances such as cellular telephones, digital cameras, and notebook-type personal computers. One of the most successful applications is laser drilling of via holes on printed circuit boards for the manufacture of cellular telephones. Other practical applications include marking, dicing, trimming, repairing, patterning, bending, and rapid prototyping. In this article, the state of the art of LDW for industrial applications in Japan, the United States, and Europe is reviewed, and its future prospects are discussed.
The Evolution of Organometallic Complexes in Organic Light-Emitting Devices
Authors: Thompson Mark 
Published: February 2011

This article is an edited transcript of the MRS Medal presentation given by Mark Thompson (University of Southern California) on November 28, 2006, at the Materials Research Society Fall Meeting in Boston. Thompson was awarded the Medal for the “development of highly efficient heavy-metal phosphor complexes.” The MRS Medal recognizes a specific outstanding recent discovery or advancement which is expected to have a major impact on the progress of any materials-related field.Successful research efforts have led to improvements in the internal efficiencies of organic light-emitting devices (OLEDs) from 25% to 100%. The electroluminescence process in OLEDs involves the formation of both singlet and triplet excitons, formed in a ratio of 1:3. There is a drive to improve spin statistics by developing compounds in which triplet excitons, in addition to singlet excitons, can be used efficiently. Success with the incorporation of heavy-metal–based phosphors into OLEDs, in which the strong spin-orbit coupling of the metal atom allows for efficient molecular phosphorescence from triplet excitons, resulted in the identification and synthesis of an iridium complex, fac-tris-phenylpyridine iridium, with internal efficiencies of 100%. This, in turn, has led to the synthesis of more than 100 iridium- and platinum-based compounds, which have become the most efficient light-emitting compounds yet discovered. Intellectual property from Thompson's research in this field has led to more than 50 U.S. patents and substantial entrepreneurial investment toward commercial applications and devices.
The Materials Science of Cosmetics
Authors: Schnittger Steven , Sinha Moitreyee 
Published: February 2011

AbstractThe cosmetics industry is increasingly using sophisticated materials and technologies in their products and to measure their effectiveness. Understanding how these products interact with skin, adhere to skin, and deliver a benefit or create a visible effect leads to better and safer products. An understanding of the optics and mechanics of skin and the cosmetics–skin interface is important for achieving various visual and functional effects. This issue reviews the underlying science and the technical challenges behind the development of materials for the personal care and cosmetics industry.
Nanotechnology and Related Safety Issues for Delivery of Active Ingredients in Cosmetics
Authors: Somasundaran P. , Mehta Somil C. , Rhein Linda , Chakraborty Soma 
Published: February 2011

AbstractNature exhibits a variety of remarkable phenomena that are useful but difficult to imitate in real life. Examples are the “touch me not” plant (Mimosa pudica), which folds up upon being attacked, or microbes that deposit on ocean vessels even under hostile conditions. Understanding the mechanisms governing these phenomena can prove powerful for developing new classes of cosmetic products. This article examines the development of novel materials with functional properties such as controlled delivery and the deposition of sensory attributes (fragrances, flavors, etc.) desirable in cosmetic products. Particularly, systems based on polymer/surfactant chemistry are explored for achieving transport and release of cosmetic and pharmaceutical molecules at desired rates. The hybrid polymers and nanogel particle systems discussed here represent new classes of materials with nanodomains that can be tuned to extract and deliver cosmetic attributes by means of changes in natural parameters such as temperature and pH. While the safety of existing nanomaterials marketed for decades has not been an issue, methods are urgently needed to validate the toxicological safety of future nanomaterials.
Challenges in Cosmetic Formulations: Appearance, Long Wear, and Comfort
Authors: Maitra Prithwiraj , Brahms John 
Published: February 2011

AbstractCosmetics are products that are designed to maintain or improve visual appearance when applied to skin. Skin is a mechanically flexible substrate that changes in chemical and surface properties during the course of the day. Sebum (an oily substance secreted by the sebaceous glands) and perspiration (a secretion of mostly salt water by the eccrine glands) as well as environmental insults work counter to the desired benefits of cosmetics on physical appearance. Recent advances in the ability to control morphology and chemical properties have led to novel materials that in turn have enabled the development of cosmetics that provide, on the one hand, a more natural look, and on the other, unique and unprecedented visual effects. Progress in understanding skin biomechanics and surface properties lead to product formulations with unprecedented wear and performance characteristics. This article reviews recent advances in the ability to control the optical, bulk, and surface properties of materials, and their application to improved cosmetic formulations.