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Highlights

Highlights

Schematic of the spin transport device. The large arrows show the configuration of the magnetic electrodes. The small arrows show the electron spins in the semiconductor. The electron spins can be read out using an ordinary voltmeter (V), or with an optical Kerr microscope (shown focusing on the device).
Schematic of the spin transport device. The large arrows show the configuration of the magnetic electrodes. The small arrows show the electron spins in the semiconductor. The electron spins can be read out using an ordinary voltmeter (V), or with an optical Kerr microscope (shown focusing on the device).
Mar 15, 2007
University of Minnesota - Twin Cities

Electrical Detection of Spin Transport in Semiconductors

In semiconductor spintronics, the spin of the electron carries information for both storage and data processing. To some extent, the electron spin can be viewed as a miniature bar magnet that interacts with a magnetic field inside the semiconductor. The orientation of the bar magnet acts as a "bit" of information. Many laboratory demonstrations of spintronics have relied on sophisticated optical techniques for reading out the spin state of electrons.
Figure 1. (Upper left) Architecture of the ion gel gated OTFT employing poly 3-hexylthiophene (P3HT) as the semiconductor and an ion gel as the high capacitance gate dielectric. (Upper right) Structure of the ionic liquid and block copolymer used to form the ion gel. (Bottom) Transient response of the OTFT to a stepped voltage input (VIN 0 to - 3V). When VD is -1V (blue trace), VOUT (blue) is 0 to -1 V. When VD is 0 V, VOUT is not modulated, as expected. Importantly, the period of the input signal is 2 ms, and the operating voltages are low.
Figure 1. (Upper left) Architecture of the ion gel gated OTFT employing poly 3-hexylthiophene (P3HT) as the semiconductor and an ion gel as the high capacitance gate dielectric. (Upper right) Structure of the ionic liquid and block copolymer used to form the ion gel. (Bottom) Transient response of the OTFT to a stepped voltage input (VIN 0 to - 3V). When VD is -1V (blue trace), VOUT (blue) is 0 to -1 V. When VD is 0 V, VOUT is not modulated, as expected. Importantly, the period of the input signal is 2 ms, and the operating voltages are low.
Mar 15, 2007
University of Minnesota - Twin Cities

Ion Gel-Gated Polymer Thin Film Transistors

A major goal of organic electronics is the development of new kinds of solution processable organic dielectric materials that can serve as gate insulators in organic thin film transistors (OTFTs).
Feb 8, 2007
University of Wisconsin - Madison

Materials Stiffer Than Diamond

T. Jaglinski, D. Kochmann, D. Stone and R.S. Lakes
For hardness and stiffness, it's long been thought that nothing beats diamond. But Roderic Lakes and Don Stone, from the University of Wisconsin MRSEC and their colleagues have made a material that is almost ten times stiffer, by embedding small particles of barium titanate in a matrix of tin.
Feb 8, 2007
Princeton University

New Superconductor Found by Sprinkling Cu Atoms

Feb 8, 2007
Princeton University

Industry/International: Nanowire Grids Polarize Ultraviolet Light

The increased speed and power of microelectronic devices has come from a steady reduction in the size of their constituent features, which has been achieved by using progressively shorter wavelengths for the photolithography used in their fabrication. Today, the most advanced production photolithography uses 193 nm ultraviolet (UV) light from an ArF excimer laser.
Jan 25, 2007
Massachusetts Institute of Technology

A New MIT-Wide Vehicle for MRSEC Knowledge Outreach

The MIT MRSEC, in collaboration with the Materials Processing Center (MPC) and the Department of Materials Science and Engineering (DMSE), has launched a new MIT-wide materials website...The MIT MRSEC, in collaboration with the Materials Processing Center (MPC) and the Department of Materials Science and Engineering (DMSE), has launched a new MIT-wide materials website designed to help interested parties navigate the diverse and sometimes confusing labyrinth of departments, labs and centers (and associated user facilities) on campus involved in materials research.
Jan 22, 2007
University of Wisconsin - Madison

Materials Integration for Micro-Controlled 3D Culture of Human Embryonic Stem Cells

Mohr J.C., de Pablo J.J., and Palecek S.P.
Human embryonic stem cells (hESCs) hold vast promise in science and medicine because of their potential to replicate indefinitely and their capability to differentiate to any cell type found in the adult. Many environmental cues, including soluble factors and intercellular signals, affect hESC differentiation and self-renewal decisions.
Jan 16, 2007
Massachusetts Institute of Technology

Quantum Dot “Sandwiches" Emit White Light

Members of IRG-III of the MIT MRSEC have demonstrated a light emitting device application of such quantum dots. They show that white light can be generated in a layered device that combines organic semiconductor layers with a single monolayer of quantum dots. The composition and the sizes of the quantum dots were chosen to cover the color spectrum required for the perception of white light, as in an incandescent light bulb. The ability to synthesize nanomaterials with nearly atomic precision
Jan 16, 2007
Massachusetts Institute of Technology

Nanocoatings Harvest Water from Fog

In the Namib Desert in Namibia, Africa, a tiny beetle is able to convert microscopic droplets of water present in a morning fog into larger sized droplets that are directed into the beetle's mouth to quench a
Figure 1. Schematic of the spin arrangement in an Fe / Cr thin film bilayer. The wavelength of the spin density wave in the Cr changes continuously as the temperature is varied. This leads to an oscillation in the magnitude of the Cr interface spin with temperature, and therefore an oscillating exchange bias.
Figure 1. Schematic of the spin arrangement in an Fe / Cr thin film bilayer. The wavelength of the spin density wave in the Cr changes continuously as the temperature is varied. This leads to an oscillation in the magnitude of the Cr interface spin with temperature, and therefore an oscillating exchange bias.
Jan 10, 2007
University of Minnesota - Twin Cities

Probing Spin Density Waves

Magnetism in metallic films and interfaces has been intensively studied since the discovery of Giant MagnetoResistance (GMR) in the late 1980s. This effect enabled fabrication of high sensitivity magnetic field sensors for the read heads in magnetic hard disks, revolutionizing magnetic recording. GMR occurs in structures where an ultra-thin "non-magnetic" film is sandwiched between two magnets, Fe / Cr / Fe being a popular example. Although often ignored, the weak magnetism of the Cr film is fascinating in its own right.

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