NIST

The US National Institute of Standards and Technology (NIST) and its partners in the US Nanoelectronic Computing Research (nCORE) consortium have awarded $10.3 million over four years to establish a spintronics research center in Mineesota.

The Center for Spintronic Materials in Advanced Information Technologies (SMART) will be led by and housed at the University of Minnesota Twin Cities and will include researchers from the Massachusetts Institute of Technology, Pennsylvania State University, Georgetown University and the University of Maryland.

Researchers from the NIST in the US and the University of Tokyo have discovered a metallic antiferromagnet (Mn₃Sn) that exhibits a large magneto-optic Kerr (MOKE) effect, despite a vanishingly small net magnetization at room temperature.

Compared to ferromagnetic materials, metallic antiferromagnets allow for faster dynamics and more densely packed spintronic devices due to the weak interactions between antiferromagnetic cells. The researchers believe that such materials hold promise for future antiferromagnetic spintronic devices, where the magnetic state could transduced optically and switched either optically or by applying current.

Mark Stiles, from the NIST's Center for Nanoscale science and technology, gave an interesting lecture titled "Spin Current: the Torque Wrench of Spintronics" in which he discussed spintronics challenges, especially for spin-torque MRAM devices:

Researchers from the National Institute of Standards and Technology (NIST) developed a new microscope, called a heterodyne magneto-optic microwave microscope (H-MOMM) that can measure the collective dynamics of elecrons spins. The microscope can measure the spin in individual magnets as small as 100 nanometers in diameter.

The NIST researchers used the H-MOMM to quantify, for the first time, the spin relaxation process—or damping—in individual nanomagnets. The results suggest that designing spintronic devices to have uniform spin waves could dramatically reduce the energy required to write a bit. They say that these results are "groundbreaking".

Researchers from the National Institute of Standards and Technology (NIST) and University of Colorado Boulder (CU) developed a new chip that uses microfluidics and magnetic switches to trap and transport magnetic beads. This low-power device may be useful for medical devices. This technology may also lead us towards "MRAM" chips used for molecular and cellular manipulation.

In the past, magnetic particle transport chips required continuous power and even cooling. This new technology manages to overcome the power and heat issues, and offers random-access two-dimensional control and non-volatile memory. The prototype chip uses 12 spin valves (commonly used as magnetic sensors in HD read heads) which are optimized for magnetic trapping. Pulses of electric current are used to switch individual spin valve magnets “on” to trap a bead, or “off” to release it, and thereby move the bead down a ladder formed by the two lines. The beads start out suspended in salt water above the valves before being trapped in the array.

Researchers from Argonne National Laboratory (ANL) and the National Institute of Standards and Technology (NIST) developed a new custom-made material that enabled them to performs measurements important for the emerging field of oxide spintronics.

The team engineered a highly ordered version of a magnetic oxide compound that naturally has two randomly distributed elements: lanthanum and strontium. The team members from ANL have mastered a technique for laying down the oxides one atomic layer at a time, allowing them to construct an exceptionally organized lattice in which each layer contains only strontium or lanthanum, so that the interface between the two components could be studied.

Paul Haney and Mark Stiles from the NIST Center for Nanoscale Science and Technology (CNST) developed a new theory of current-induced torques that generalizes the relationship between spin transfer torques, total angular momentum current, and mechanical torques. This new theory is also applicable to more materials than previous theories.

The basic idea is that there are two types of current-induced torques: a mechanical torque acting on the lattice, and a spin transfer torque (STT) acting on the magnetization. STT is a known phenomenon that is the basic of several technologies such as STT-MRAM and nanoscale microwave oscillators.

Researchers working at the National Institute of Standards and Technology (NIST) have demonstrated for the first time the existence of a key magnetic—as opposed to electronic—property of specially built semiconductor devices. This discovery raises hopes for even smaller and faster gadgets that could result from magnetic data storage in a semiconductor material, which could then quickly process the data through built-in logic circuits controlled by electric fields.

In a new paper, researchers from NIST, Korea University and the University of Notre Dame have confirmed theorists’ hopes that thin magnetic layers of semiconductor material could exhibit a prized property known as antiferromagnetic coupling—in which one layer spontaneously aligns its magnetic pole in the opposite direction as the next magnetic layer. The discovery of antiferromagnetic coupling in metals was the basis of the 2007 Nobel Prize in Physics, but it is only recently that it has become conceivable for semiconductor materials. Semiconductors with magnetic properties would not only be able to process data, but also store it.

Researchers at the National Institute of Standards and Technology have made the first confirmed “spintronic” device incorporating organic molecules, a potentially superior approach for innovative electronics that rely on the spin, and associated magnetic orientation, of electrons. The physicists created a nanoscale test structure to obtain clear evidence of the presence and action of specific molecules and magnetic switching behavior.

Spintronic devices usually are made of inorganic materials. The use of organic molecules may be preferable, because electron spins can be preserved for longer time periods and distances, and because these molecules can be easily manipulated and self-assembled. However, until now, there has been no experimental confirmation of the presence of molecules in a spintronic structure. The new NIST results are expected to assist in the development of practical molecular spintronic devices.

A gyromagnetic effect discovered by Albert Einstein and Dutch physicist Wander Johannes de Haas - the rotation of an object caused by a change in magnetization - has been measured at micrometer-scale dimensions for the first time at the National Institute of Standards and Technology (NIST). The new method may be useful in the development and optimization of thin film materials for read heads, memories and recording media for magnetic data storage and spintronics, an emerging technology that relies on the spin of electrons instead of their charge as in conventional electronics.