Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Moving forward, spin goes sideways

10.10.2011
Improvements to specialized valves that separate spin and electron currents may lead to higher-density magnetic media

Building electronic devices that work without needing to actually transport electrons is a goal of spintronics researchers, since this could lead to: reduced power consumption, lower levels of signal noise, faster operation, and denser information storage. However, the generation of pure spin currents remains a challenge.

Now, YoshiChika Otani and colleagues at the RIKEN Advanced Science Institute, Wako, and five other research institutes in Japan and China, have produced a large spin current in an important spintronic device called a lateral spin valve.

Spintronic devices store information in the spin of electrons, rather than in their density or energy level. Information flows through the propagating waves of spin orientation, while electrical charges remain stationary. Inside a lateral spin valve, a current of electron spins—but not of electron charges—is injected into a nonmagnetic wire through a ferromagnetic contact.

The current travels down the wire, and creates an output voltage across a second ferromagnetic contact, which serves as the output of the device. This lateral arrangement is important because it allows charge and spin currents to flow independently and permits the use of multiple terminals. However, while a practical lateral spin valve would require a large output voltage, previous devices had produced only 1 microvolt or less.

To increase the output voltage of their device, Otani and colleagues concentrated on the quality of the junction between the two ferromagnetic contacts and the non-magnetic, silver wire. Between the wire and the ferromagnets made of nickel and iron, the researchers placed a thin layer of magnesium oxide, which served to increase the efficiency of spin injection. They found that the straightforward annealing of their device at 400 °C in a mostly nitrogen environment reduced the quantity of oxygen in this interfacial layer.

This lowered junction resistance by a factor of up to 1,000, and increased the efficiency of spin injection into the silver wire. As a result, the output voltage reached 220 microvolts, which is more than 100 times greater than that of existing devices. In addition, the research team was able to observe the injected spins rotating, of what is technically known as precessing, in response to a magnetic field along the entire length of their 6-micrometer silver wire, confirming high spin injection efficiency.

The spin valve could be further improved, says Otani, by using cobalt–iron ferromagnets, which are known to have greater spin injection efficiency than nickel–iron, with potential near-term application as sensors in high-density magnetic media.

The corresponding author for this highlight is based at the Quantum Nano-Scale Magnetics Team, RIKEN Advanced Science Institute

Reference:
Fukuma, Y., Wang, L., Idzuchi, H., Takahashi, S., Maekawa, S. & Otani, Y. Giant enhancement of spin accumulation and long-distance spin precession in metallic lateral spin valves. Nature Materials 10, 527–531 (2011).

gro-pr | Research asia research news
Further information:
http://www.riken.jp
http://www.researchsea.com

Further reports about: Advanced Investigator Grant MOVING RIKEN electron spin

More articles from Physics and Astronomy:

nachricht Further Improvement of Qubit Lifetime for Quantum Computers
09.12.2016 | Forschungszentrum Jülich

nachricht Electron highway inside crystal
09.12.2016 | Julius-Maximilians-Universität Würzburg

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Electron highway inside crystal

Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.

Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Researchers identify potentially druggable mutant p53 proteins that promote cancer growth

09.12.2016 | Life Sciences

Scientists produce a new roadmap for guiding development & conservation in the Amazon

09.12.2016 | Ecology, The Environment and Conservation

Satellites, airport visibility readings shed light on troops' exposure to air pollution

09.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>