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 New NASA study improves search for habitable worlds
20.10.2017 | NASA/Goddard Space Flight Center

nachricht Physics boosts artificial intelligence methods
19.10.2017 | California Institute of Technology

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: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Terahertz spectroscopy goes nano

20.10.2017 | Information Technology

Strange but true: Turning a material upside down can sometimes make it softer

20.10.2017 | Materials Sciences

NRL clarifies valley polarization for electronic and optoelectronic technologies

20.10.2017 | Interdisciplinary Research

VideoLinks
B2B-VideoLinks
More VideoLinks >>>