PRESS-NEWS.org - Press Release Distribution
PRESS RELEASES DISTRIBUTION

Silicon spin transistors heat up and spins last longer

The goal: Room-temperature spintronic computers

Silicon spin transistors heat up and spins last longer
2011-03-15
(Press-News.org) SALT LAKE CITY, March 15, 2011 - University of Utah researchers built "spintronic" transistors and used them to align the magnetic "spins" of electrons for a record period of time in silicon chips at room temperature. The study is a step toward computers, phones and other spintronic devices that are faster and use less energy than their electronic counterparts.

"Electronic devices mostly use the charge of the electrons - a negative charge that is moving," says Ashutosh Tiwari, an associate professor of materials science and engineering at the University of Utah. "Spintronic devices will use both the charge and the spin of the electrons. With spintronics, we want smaller, faster and more power-efficient computers and other devices."

Tiwari and Ph.D. student Nathan Gray report their creation of room-temperature, spintronic transistors on a silicon semiconductor this month in the journal Applied Physics Letters. The research - in which electron "spin" aligned in a certain way was injected into silicon chips and maintained for a record 276 trillionths of a second - was funded by the National Science Foundation.

"Almost every electronic device has silicon-based transistors in it," Gray says. "The current thrust of industry has been to make those transistors smaller and to add more of them into the same device" to process more data. He says his and Tiwari's research takes a different approach.

"Instead of just making transistors smaller and adding more of them, we make the transistors do more work at the same size because they have two different ways [electron charge and spin] to manipulate and process data," says Gray.

A Quick Spin through Spintronics

Modern computers and other electronic devices work because negatively charged electrons flow as electrical current. Transistors are switches that reduce computerized data to a binary code of ones or zeros represented by the presence or absence of electrons in semiconductors, most commonly silicon.

In addition to electric charge, electrons have another property known as spin, which is like the electron's intrinsic angular momentum. An electron's spin often is described as a bar magnet that points up or down, which also can represent ones and zeroes for computing.

Most previous research on spintronic transistors involved using optical radiation - in the form of polarized light from lasers - to orient the electron spins in non-silicon materials such as gallium arsenide or organic semiconductors at supercold temperatures.

"Optical methods cannot do that with silicon, which is the workhorse of the semiconductor and electronics industry, and the industry doesn't want to retool for another material," Tiwari says.

"Spintronics will become useful only if we use silicon," he adds.

The Experiment

In the new study, Tiwari and Gray used electricity and magnetic fields to inject "spin polarized carriers" - namely, electrons with their spins aligned either all up or all down - into silicon at room temperature.

Their trick was to use magnesium oxide as a "tunnel barrier" to get the aligned electron spins to travel from one nickel-iron electrode through the silicon semiconductor to another nickel-iron electrode. Without the magnesium oxide, the spins would get randomized almost immediately, with half up and half down, Gray says.

"This thing works at room temperature," Tiwari says. "Most of the devices in earlier studies have to be cooled to very low temperatures" - colder than 200 below zero Fahrenheit - to align the electrons' spins either all up or all down. "Our new way of putting spin inside the silicon does not require any cooling."

The experiment used a flat piece of silicon about 1 inch long, about 0.3 inches wide and one-fiftieth of an inch thick. An ultra-thin layer of magnesium oxide was deposited on the silicon wafer. Then, one dozen tiny transistors were deposited on the silicon wafer so they could be used to inject electrons with aligned spins into the silicon and later detect them.

Each nickel-iron transistor had three contacts or electrodes: one through which electrons with aligned spins were injected into the silicon and detected, a negative electrode and a positive electrode used to measure voltage.

During the experiment, the researchers send direct current through the spin-injector electrode and negative electrode of each transistor. The current is kept steady, and the researchers measure variations in voltage while applying a magnetic field to the apparatus

"By looking at the change in the voltage when we apply a magnetic field, we can find how much spin has been injected and the spin lifetime," Tiwari says.

A 328 Nanometer, 276 Picosecond Step for Spintronics

For spintronic devices to be practical, electrons with aligned spins need to be able to move adequate distances and retain their spin alignments for an adequate time.

During the new study, the electrons retained their spins for 276 picoseconds, or 276 trillionths of a second. And based on that lifetime, the researchers calculate the spin-aligned electrons moved through the silicon 328 nanometers, which is 328 billionths of a meter or about 13 millionths of an inch.

"It's a tiny distance for us, but in transistor technology, it is huge," Gray says. "Transistors are so small today that that's more than enough to get the electron where we need it to go."

"Those are very good numbers," Tiwari says. "These numbers are almost 10 times bigger than what we need [for spintronic devices] and two times bigger than if you use aluminum oxide" instead of the magnesium oxide in his study.

He says Dutch researchers previously were able to inject aligned spins into silicon using aluminum oxide as the "tunneling medium," but the new study shows magnesium oxide works better.

The new study's use of electronic spin injection is much more practical than using optical methods such as lasers because lasers are too big for chips in consumer electronic devices, Tiwari says.

He adds that spintronic computer processors require little power compared with electronic devices, so a battery that may power an electronic computer for eight hours might last more than 24 hours on a spintronic computer.

Gray says spintronics is "the next big step to push the limits of semiconductor technology that we see in every aspect of our lives: computers, cell phones, GPS (navigation) devices, iPods, TVs."



INFORMATION:

University of Utah Public Relations
201 Presidents Circle, Room 308
Salt Lake City, Utah 84112-9017
(801) 581-6773 fax: (801) 585-3350
www.unews.utah.edu


[Attachments] See images for this press release:
Silicon spin transistors heat up and spins last longer

ELSE PRESS RELEASES FROM THIS DATE:

Parental monitoring of opposite-gender child may decrease problem drinking in young adults

2011-03-15
Young adults whose parents monitor their social interactions may be less likely to display impulsive behavior traits and to have alcohol-related problems, a new study suggests. The level of monitoring is linked to parenting style, and the link is stronger with the parent of the opposite gender. This study is one of the first to explore the link between parenting style and parental monitoring, as well as to explore the monitoring style of each parent individually, says Julie A. Patock-Peckham, Ph.D., Assistant Professor of Psychology & Neuroscience at Baylor University ...

New research demonstrates language learners' creativity

2011-03-15
(Washington, DC) New research published in Language, the journal of the Linguistic Society of America (LSA) firmly establishes that language learning goes well beyond simple imitation, and in fact that language learners are quite creative and remarkably smart. Not only are learners able to generalize grammatical restrictions to new words in a category – in this case, made-up adjectives – but they also do not learn these restrictions in situations where they can be attributed to some irrelevant factor. This point is driven home in an article, "Learning what not to say: ...

Nursing home boom in China has little government involvement

2011-03-15
PROVIDENCE, R.I. [Brown University] — A nursing home industry is booming in China as a rapid increase in the proportion of its elderly population forces a nationwide shift from traditional family care to institutional care, according to new research by Brown University gerontologists. The study, led by Zhanlian Feng, assistant professor of community health, and published online in the Journal of the American Geriatrics Society, is the first systematic documentation of the growth and operation of nursing homes in Chinese cities. The demographics driving the trend, however, ...

Particle Characterization Ensures Consistent Roller Compaction Processes

2011-03-15
Roller Compaction Process Optimization using FBRM Particle Characterization In roller compaction, particle distribution is recognized as one of the most critical parameters affecting downstream process performance and product quality. The particle distribution affects the following unit operations: (graphic) A roller compaction process is designed to yield consistent downstream tablet compression resulting in uniform dissolution and content uniformity. A successful process produces a granule with consistent particle size distribution, density and porosity control. ...

Tampa Hip Hop Artist "Prophit" New Single "This My Club" Featured In Action Thriller Film "Limitless"

2011-03-15
Limitless, a paranoia-fueled action thriller about an unpublished writer whose life is transformed by a top-secret smart drug that allows him to use 100% of his brain and become a perfect version of himself. His enhanced abilities soon attract shadowy forces that threaten his new life in this darkly comic and provocative film. "This was a great opportunity for me and my manager Mathew Steele to secure a spot in a film such as Limitless" states Prophit. "I'm learning the importance of building relationships with the right people in this business", he further states. In ...

Lighthouse for the Blind-Saint Louis Partnering with Zep, Inc. and Envision, Inc. In Manufacturing Venture that Will Employ Blind & Visually Impaired People

2011-03-15
Lighthouse for the Blind-Saint Louis, a not-for-profit corporation that assists legally blind people maintain dignity and independence by offering Employment, Education and Support Services, announces a partnership agreement with Zep, Inc. of Atlanta, Georgia, and Envision, Inc. of Wichita, Kansas, to manufacture a new line of co-branded aerosol metered air freshener products. John Thompson, President, Lighthouse for the Blind-St. Louis, said, "This new partnership with Zep, Inc. and Envision should have a profound impact on our ability to grow our business and expand ...

DIG Coaching Practice presents "Quantitative Electroencephalography and Diagnosing ADHD. Say What?" March 23 on Attention Talk Radio with host Jeff Copper and Dr. Michael Linden.

2011-03-15
DIG Coaching Practice presents Attention Talk Radio with host, Jeff Copper, attention coach, and Dr. Michael Linden on quantitative electroencephalography (QEEG) in the diagnosis of attention deficit hyperactivity disorder (ADHD). Dr. Linden addresses the pitfalls of diagnosing ADHD based only on symptoms and the advantages of using QEEG to accurately diagnose ADHD. Dr. Michael Linden is a licensed clinical psychologist, marriage, family and child therapist, and a BCIA Fellow and nationally certified neurofeedback and biofeedback therapist since 1984. He is the director ...

Blog Family Media - Moms 4 Sale Create Ultimate Classified Site for Moms

2011-03-15
Blog Family Media, a new on the scene media group, forged together in the idea of giving moms the advantage and power when it comes to purchases; has created a classified website and exclusive networking site. These two sites give moms the venue for posting their own classified, seeking a classified and connecting with other moms âEUR" without the âEURœickâEUR factor of most mainstream sites. Moms 4 Sale (www.moms4sale.com) is your standard issues classified listing website but with one major component âEUR" âEURœ4 Moms, By MomsâEUR. Moms 4 Sale gives moms a safe venue ...

MyCUsurvey.com National Member Satisfaction Research Reveals Credit Unions Have Less Appeal for Younger Members

2011-03-15
MyCUsurvey.com (www.mycusurvey.com), a new online, low-cost, phone and web-based member research tool designed specifically for the credit union industry, today revealed the results of its first national survey of credit union member satisfaction nationwide. The survey of 5,000 credit union members across the country was conducted in late fall 2010 and is designed to provide a benchmark against which MyCUsurvey.com customers can gauge their own credit union's performance. The most recent survey reveals three key factors that show credit unions are at risk and need to dramatically ...

Williams Travel and Cruises to participate in first-ever "National Plan a Vacation Week" March 15-21st

2011-03-15
This week marks the official launch of National Plan a Vacation Week, a new nationally registered annual event. Dana Williams of Williams Travel and Cruises is one of the select travel agents to participate in this travel agent extravaganza, which showcases the best vacation experiences during this important travel booking window. Williams Travel and Cruises has their own personal micro-website as part of the event: http://www.planavacationweek.com/williamstravel. National Plan a Vacation Week enables anyone looking forward to planning their vacations access to great ...

LAST 30 PRESS RELEASES:

Call for papers: 14th Asia-Pacific Conference on Transportation and the Environment (APTE 2025)

A novel disturbance rejection optimal guidance method for enhancing precision landing performance of reusable rockets

New scan method unveils lung function secrets

Searching for hidden medieval stories from the island of the Sagas

Breakthrough study reveals bumetanide treatment restores early social communication in fragile X syndrome mouse model

Neuroscience leader reveals oxytocin's crucial role beyond the 'love hormone' label

Twelve questions to ask your doctor for better brain health in the new year

Microelectronics Science Research Centers to lead charge on next-generation designs and prototypes

Study identifies genetic cause for yellow nail syndrome

New drug to prevent migraine may start working right away

Good news for people with MS: COVID-19 infection not tied to worsening symptoms

Department of Energy announces $179 million for Microelectronics Science Research Centers

Human-related activities continue to threaten global climate and productivity

Public shows greater acceptance of RSV vaccine as vaccine hesitancy appears to have plateaued

Unraveling the power and influence of language

Gene editing tool reduces Alzheimer’s plaque precursor in mice

TNF inhibitors prevent complications in kids with Crohn's disease, recommended as first-line therapies

Twisted Edison: Bright, elliptically polarized incandescent light

Structural cell protein also directly regulates gene transcription

Breaking boundaries: Researchers isolate quantum coherence in classical light systems

Brain map clarifies neuronal connectivity behind motor function

Researchers find compromised indoor air in homes following Marshall Fire

Months after Colorado's Marshall Fire, residents of surviving homes reported health symptoms, poor air quality

Identification of chemical constituents and blood-absorbed components of Shenqi Fuzheng extract based on UPLC-triple-TOF/MS technology

'Glass fences' hinder Japanese female faculty in international research, study finds

Vector winds forecast by numerical weather prediction models still in need of optimization

New research identifies key cellular mechanism driving Alzheimer’s disease

Trends in buprenorphine dispensing among adolescents and young adults in the US

Emergency department physicians vary widely in their likelihood of hospitalizing a patient, even within the same facility

Firearm and motor vehicle pediatric deaths— intersections of age, sex, race, and ethnicity

[Press-News.org] Silicon spin transistors heat up and spins last longer
The goal: Room-temperature spintronic computers