Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Atomic-level crystal gazing

11.04.2011
Revelation of the crystallization mechanism that enables fast writing of data to DVDs shows potential for quicker data storage in the future

Some 300 exabytes (3 × 1020 bytes) of information were stored in electronic media—magnetic disks and tapes or optical disks—throughout the world by 2007. Yet, the demand for electronic storage grows daily, driving an ever-increasing need to pack data into smaller volumes in quicker time.


Figure 1: Pulses of light alter the atomic bonds (red) in the material AIST, enabling quick storage and deletion of data. Copyright : 2011 Masaki Takata

By studying how laser pulses alter the atomic structure of data-storage materials, a research team in Japan has uncovered a fundamental mechanism that could aid in the design of even faster information storage in the future[1]. The finding was published by Masaki Takata from the RIKEN SPring-8 Center, Harima, Shinji Kohara from the Japan Synchrotron Radiation Research Institute/SPring-8, Noboru Yamada from Panasonic Corporation and a team of scientists from Japan, Germany and Finland.

Rewritable memory, such as the random-access memory found in computers or on DVDs, is based on a phase change in specific types of materials in which the atoms change from one stable arrangement to another. Pulses of laser light can induce a phase change, a process known as ‘writing,’ and the material’s phase can be identified by ‘reading’ its signature optical properties.

To provide the first full understanding of the atomic structure of one such phase-change material, AgInSbTe (AIST)—often used in rewritable DVDs—Takata and his colleagues combined state-of-the-art materials-analysis techniques and theoretical modeling. A pulse of light can change AIST from an amorphous state, in which the atoms are disordered, into a crystalline phase in which the atoms are form an ordered-lattice structure. This process of crystallization happens in just a few tens of nanoseconds: the faster the crystallization, the faster data can be written and erased. No-one understood, however, why phase changes in AIST were so fast.

The teams’ analyses and modeling showed that AIST crystallizes in a different way to other commercially available phase-change materials. They found that crystallization of AIST is a simple process: the laser light excites the bonding electrons and causes them to move. A central atom of antimony (Sb) switches between one long (amorphous) and one short (crystalline) bond without any bond breaking (Fig. 1). “We hope to verify this bond-interchange model in the near future,” says Takata. “Crystallization is the storage-rate-limiting process in all phase-change materials, and an atomistic understanding of it is essential.”

The researchers also discovered that the absence of cavities within the crystal structure contributes to the faster writing speeds on AIST. This contrasts starkly with the alternative material germanium antimony telluride in which 10% of lattice sites in are empty.

The corresponding author for this highlight is based at the Structural Materials Science Laboratory, RIKEN SPring-8 Center

to nanosecond recrystallization dynamics in AgInSbTe phase-change materials'
Journal information
[1] Matsunaga, T., Akola, J., Kohara, S., Honma, T., Kobayashi, K., Ikenaga, E., Jones, R.O., Yamada, N., Takata, M. & Kojima, R. From local structure to nanosecond recrystallization dynamics in AgInSbTe phase-change materials. Nature Materials 10, 129–134 (2011)

gro-pr | Research asia research news
Further information:
http://www.rikenresearch.riken.jp/eng/research/6562
http://www.researchsea.com

Further reports about: Atomic-level DVD RIKEN SPring-8 atomic structure laser light

More articles from Information Technology:

nachricht Construction of practical quantum computers radically simplified
05.12.2016 | University of Sussex

nachricht UT professor develops algorithm to improve online mapping of disaster areas
29.11.2016 | University of Tennessee at Knoxville

All articles from Information Technology >>>

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 >>>