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The solution to a 7-decade mystery is crystal-clear to FSU chemist
October 22, 2007A Florida State University researcher has helped solve a scientific mystery that stumped chemists for nearly seven decades. In so doing, his team's findings may lead to the development of more-powerful computer memories and lasers.
Naresh S. Dalal, the Dirac Professor of Chemistry and Biochemistry at FSU, recently collaborated with three colleagues, Jorge Lasave, Sergio Koval and Ricardo Migoni, all of the Universidad Nacional de Rosario in Argentina, to determine why a certain type of crystal known as ammonium dihydrogen phosphate, or ADP, behaves the way it does.
"ADP was discovered in 1938," Dalal said. "It was observed to have some unusual electrical properties that weren't fully understood -- and for nearly 70 years, scientists have been perplexed by these properties. Using the supercomputer at SCRI (FSU's Supercomputer Computations Research Institute), we were able to perform in-depth computational analyses that explained for the very first time what causes ADP to have these unusual properties."
ADP, like many crystals, exhibits an electrical phenomenon known as ferroelectricity. Ferroelectric materials are analogous to magnets in that they maintain a positively charged and a negatively charged pole below a certain temperature that is characteristic for each compound.
"Ferroelectric materials can stay in a given state of charge for a long time -- they retain their charge after the external electrical source is removed," Dalal said. "This has made ADP and other materials like it very useful for storing and transmitting data.
ADP is commonly used in computer memory devices, fiber optic technology, lasers and other electro-optic applications."
What researchers found perplexing about ADP was that it often displays a very different electrical phase -- one known as antiferroelectricity.
"With antiferroelectricity, one layer of molecules in a crystal has a plus and a minus pole, but in the next layer, the charges are reversed," Dalal said. "You see this reversal of charges, layer by layer, throughout the crystal."
Using the supercomputer at SCRI enabled Dalal and his colleagues to perform numerous highly complex calculations that couldn't be duplicated in a laboratory environment. For example, they were able to theoretically alter the angles of ADP's ammonium ions and then measure the effects on the crystal's electrical charge. That approach ultimately led to their solution to the seven-decade mystery.
"We found that the position of the ammonium ions in the compound, as well as the presence of stresses or defects in the crystal, determine whether it behaves in a ferroelectric or antiferroelectric manner," Dalal said.
The team's research is important for two main reasons, Dalal said: "First, this allows us to further understand how to design new materials with both ferroelectric and antiferroelectric properties. Doing so could open new doors for computer memory technology -- and possibly play a role in the development of quantum computers.
"Second, our research opens up new ways of testing materials," Dalal said. "Using supercomputers, we can quickly perform tests to see how materials would react under a variety of conditions. Many such tests can't even be performed in the lab."
Florida State University
ADP, like many crystals, exhibits an electrical phenomenon known as ferroelectricity. Ferroelectric materials are analogous to magnets in that they maintain a positively charged and a negatively charged pole below a certain temperature that is characteristic for each compound.
"Ferroelectric materials can stay in a given state of charge for a long time -- they retain their charge after the external electrical source is removed," Dalal said. "This has made ADP and other materials like it very useful for storing and transmitting data.
ADP is commonly used in computer memory devices, fiber optic technology, lasers and other electro-optic applications."
What researchers found perplexing about ADP was that it often displays a very different electrical phase -- one known as antiferroelectricity.
"With antiferroelectricity, one layer of molecules in a crystal has a plus and a minus pole, but in the next layer, the charges are reversed," Dalal said. "You see this reversal of charges, layer by layer, throughout the crystal."
Using the supercomputer at SCRI enabled Dalal and his colleagues to perform numerous highly complex calculations that couldn't be duplicated in a laboratory environment. For example, they were able to theoretically alter the angles of ADP's ammonium ions and then measure the effects on the crystal's electrical charge. That approach ultimately led to their solution to the seven-decade mystery.
"We found that the position of the ammonium ions in the compound, as well as the presence of stresses or defects in the crystal, determine whether it behaves in a ferroelectric or antiferroelectric manner," Dalal said.
The team's research is important for two main reasons, Dalal said: "First, this allows us to further understand how to design new materials with both ferroelectric and antiferroelectric properties. Doing so could open new doors for computer memory technology -- and possibly play a role in the development of quantum computers.
"Second, our research opens up new ways of testing materials," Dalal said. "Using supercomputers, we can quickly perform tests to see how materials would react under a variety of conditions. Many such tests can't even be performed in the lab."
Florida State University
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Vise squad: Putting the squeeze on a crystal leads to novel electronics
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'Instant on' computing
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Domain Walls that Conduct Electricity
The logic and memory functions of future electronic devices could shrink dramatically - to one or two nanometers (billionths of a meter) instead of the many tens of nanometers that characterize today's most advanced elements - if a way can be found to control domain walls, the ultrathin transition zones that separate regions of a material having different magnetic, electric, or other properties.
Capture of nanomagnetic 'fingerprints' a boost for next-generation information storage media
In the race to develop the next generation of storage and recording media, a major hurdle has been the difficulty of studying the tiny magnetic structures that will serve as their building blocks.
Polymer electric storage, flexible and adaptable
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Disorder enables extreme sensitivity in piezoelectric materials
A research team working at the National Institute of Standards and Technology (NIST) has found an explanation for the extreme sensitivity to mechanical pressure or voltage of a special class of solid materials called relaxors.
Landmark Modeling Study at Penn Reveals How Ferroelectric Computer Memory Works
A collaboration of University of Pennsylvania chemists and engineers has performed multi-scale modeling of ferroelectric domain walls and provided a new theory of behavior for domain-wall motion, the "sliding wall" that separates ferroelectric domains and makes high-density ferroelectric RAM (FeRAM) possible.
Colluding with colloids: Scientists make liquid crystal discovery
What do milk, paint, ink and liquid crystals have in common? Colloids. Findings of Kent State University scientists indicate that manipulating the size of colloids, micron-sized or nanometer-sized particles, can produce huge changes in the material properties of liquid crystals.
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Principles and Applications of Ferroelectrics and Related Materials (Oxford Classic Text in the Physical Sciences) by M. E. Lines (Author), A. M. Glass (Author) Standard text for studying ferroelectric and pyroelectric devices. Develops the modern theory of ferroelectricity in terms of soft modes and lattice dynamics, covering modern techniques of measurement such as x-ray, optic, and neutron scattering. First published in 1977. Softcover. |
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Ferroelectric Crystals by Franco Jona (Author), G. Shirane (Author) | |
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Physics of Ferroelectrics: A Modern Perspective (Topics in Applied Physics) by Karin M. Rabe (Author), Karin M. Rabe (Editor), Charles H. Ahn (Editor), Jean-Marc Triscone (Editor) During the past two decades, revolutionary breakthroughs have occurred in the understanding of ferroelectric materials, both from the perspective of theory and experiment. First principles approaches, including the Berry phase formulation of ferroelectricity, now allow accurate, quantitative predictions of material properties, and single crystalline thin films are now available for fundamental studies of these materials. In addition, the need for high dielectric constant insulators and nonvolatile memories in semiconductor applications has motivated a renaissance in the investigation of these materials. This book addresses the paradigmatic shifts in understanding brought about by these breakthroughs, including the consideration of novel fabrication methods of single crystalline... |
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Nanoscale Phenomena in Ferroelectric Thin Films (Multifunctional Thin Film Series) by Seungbum Hong (Editor) Nanoscale Phenomena in Ferroelectric Thin Films presents the recent advances in the field of nanoscale science and engineering of ferroelectric thin films. It consists of two main parts: electrical characterization in nanoscale ferroelectric capacitor, and nano domain manipulation and visualization in ferroelectric materials. Well-known leading experts both in relevant academia and industry over the world (U.S., Japan, Germany, Switzerland, Korea) were invited to contribute to each chapter. The objectives of the book are to provide the reader with the information needed to 1.) build, see and manipulate domain structures; 2.) understand the unexplained macroscopic phenomena; and 3.) create ferroelectric thin film that shows novel and significantly improved physical, chemical... |
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Ferroelectric Devices, Second Edition by Kenji Uchino (Author) Discover a Strategy to Develop Bestselling Ferroelectric Devices Updating its bestselling predecessor, Ferroelectric Devices, Second Edition assesses the last decade of developments—and setbacks—in the commercialization of ferroelectricity. Field pioneer and esteemed author Uchino provides insight into why this relatively nascent and interdisciplinary process has failed so far without a systematic accumulation of fundamental knowledge regarding materials and device development. Filling the informational void, this collection of information reviews state-of-the-art research and development trends reflecting nano and optical technologies, environmental regulation, and alternative energy sources. Like the first edition, which became a standard... |
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Ferroelectric Memories by James F. Scott (Author) Ferroelectric memories have changed in 10 short years from academic curiosities of the university research labs to commercial devices in large-scale production. This is the first text on ferroelectric memories that is not just an edited collection of papers by different authors. Intended for applied physicists, electrical engineers, materials scientists and ceramists, it includes ferroelectric fundamentals, especially for thin films, circuit diagrams and processsing chapters, but emphazises device physics. Breakdown mechanisms, switching kinetics and leakage current mechanisms have lengthly chapters devoted to them. The book will be welcomed by research scientists in industry and government laboratories and in universities. It also contains 76 problems for students, making it particularly... |
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Electromechanical Properties in Composites Based on Ferroelectrics (Engineering Materials and Processes) by Vitaly Yu. Topolov (Author), Christopher R. Bowen (Author) "Electromechanical Properties in Composites Based on Ferroelectrics" discusses the latest theoretical and experimental results on the effective electromechanical (piezoelectric, dielectric and elastic) properties in piezo-composites based on ferroelectrics. For the last decades, single-crystal, bulk ceramic and thin-film ferroelectrics have found a number of various applications as a result of their remarkable piezoelectric properties. Recent work in the field of smart materials demonstrates that both ferroelectricity and piezoelectricity represent an important link between solid state science and engineering. "Electromechanical Properties in Composites Based on Ferroelectrics" investigates the problem of prediction and non-monotonicity of the effective electromechanical properties in... |
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Ferroelectric Devices (Materials Engineering, 16) by Kenji Uchino (Author) A comprehensive introduction to the fundamentals of ferroelectrics, including available materials, device designs, drive/control techniques, and essential applications - examining high-permittivity dielectrics, piezoelectric devices, pyroelectric sensors, and electro-optic devices. It focuses on highly adaptive polycrystalline ceramics and other materials used in thin/thick film devices. The book features the author's exclusive device development method. |
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Ferroelectric semiconductors by V. M Fridkin (Author) | |
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Ferroelectric Polymers (Plastics Engineering, No 28) by Hari Singh Nalwa (Editor) Reflecting the explosion of information in the science of polar polymers--in both novel materials and industrial applications -- this outstanding reference covers the chemistry and physics of polymeric materials and their uses in the fields of electronics, photonics, and biomedical engineering. |
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