Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Argonne scientists use unique diamond anvils to view oxide glass structures under pressure

14.11.2007
Researchers at the U.S. Department of Energy's Argonne National Laboratory have used a uniquely-constructed perforated diamond cell to investigate oxide glass structures at high pressures in unprecedented detail.

Argonne physicist Chris Benmore and postdoctoral appointee Qiang Mei, along with colleagues at the University of Arizona, used microscopic laser-perforated diamond anvil cells to generate pressures of up to 32 gigapascals (GPa) – roughly one-tenth the pressure at the center of the Earth. By "squashing" vitreous (glassy) arsenic oxide samples between the anvils, the researchers were able to determine the mechanism behind the structure's atypical behavior under high-pressure.

This research may have far-reaching affects in the geophysical sciences, Benmore said, because oxide glasses and liquids represent a significant percentage of the materials that make up the Earth. For example, knowing the atomic structure of oxide materials at high pressures may give scientists a window on the behaviors of magma during the formation of the early Earth and moon. "We now have a technique where we can look a lot of different silicate glasses that are relevant to the Earth's process and at the complex behaviors of the melts that formed the Earth’s mantle," he said.

During their investigation, Benmore and Mei noticed that if arsenic oxide was subjected to high pressures the material underwent an unusual transformation at about 20 GPa, as the color of the compound changed from transparent to red. However, they did not know the atomic cause for this behavior.

By performing x-ray pair distribution function experiments at Argonne's Advanced Photon Source (APS), however, Benmore and Mei were able to see the atomic reconfiguration that produced the color change. Arsenic oxide, at normal pressures, typically exists in isolated molecular "cages" in which four arsenic atoms are surrounded by three oxygen atoms apiece – each of the six oxygen atoms is bounded to two arsenic atoms. When the pressure rose above 20 GPa, however, many of these molecular cages collapsed, creating new isomers in which each arsenic atom was bonded to six oxygen atoms.

Regular diamond anvils could not be used because they caused a great deal of background scattering that obscured the signal from the material. Previous experiments on vitreous materials had used mechanically drilled diamond anvil cells to create the high pressures, but these routinely failed at pressures above 15 GPa. This experiment involved one of the first-ever uses of laser-perforated diamond anvils combined with micro-focused high energy x-ray diffraction techniques, which have the ability to generate high pressures without also producing background noise.

Benmore hopes to extend his research to liquid oxides and silicates by heating them pass their melting points. By doing so, he expects to gain a better understanding of the structural transition, which is expected to occur more abruptly and be reversible in the liquid phases of these materials.

Angela Hardin | EurekAlert!
Further information:
http://www.anl.gov

More articles from Materials Sciences:

nachricht Beyond conventional solution-process for 2-D heterostructure
22.06.2018 | Science China Press

nachricht Graphene assembled film shows higher thermal conductivity than graphite film
22.06.2018 | Chalmers University of Technology

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Temperature-controlled fiber-optic light source with liquid core

In a recent publication in the renowned journal Optica, scientists of Leibniz-Institute of Photonic Technology (Leibniz IPHT) in Jena showed that they can accurately control the optical properties of liquid-core fiber lasers and therefore their spectral band width by temperature and pressure tuning.

Already last year, the researchers provided experimental proof of a new dynamic of hybrid solitons– temporally and spectrally stationary light waves resulting...

Im Focus: Overdosing on Calcium

Nano crystals impact stem cell fate during bone formation

Scientists from the University of Freiburg and the University of Basel identified a master regulator for bone regeneration. Prasad Shastri, Professor of...

Im Focus: AchemAsia 2019 will take place in Shanghai

Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.

Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...

Im Focus: First real-time test of Li-Fi utilization for the industrial Internet of Things

The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.

Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.

Im Focus: Sharp images with flexible fibers

An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.

Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Munich conference on asteroid detection, tracking and defense

13.06.2018 | Event News

2nd International Baltic Earth Conference in Denmark: “The Baltic Sea region in Transition”

08.06.2018 | Event News

ISEKI_Food 2018: Conference with Holistic View of Food Production

05.06.2018 | Event News

 
Latest News

Graphene assembled film shows higher thermal conductivity than graphite film

22.06.2018 | Materials Sciences

Fast rising bedrock below West Antarctica reveals an extremely fluid Earth mantle

22.06.2018 | Earth Sciences

Zebrafish's near 360 degree UV-vision knocks stripes off Google Street View

22.06.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>