Living metals

Apr 22, 2005

Using Synchrotron x-ray microbeams, a research team from the Max Planck Institute for Metals Research in Stuttgart and the ESRF has been able to observe for the first time that the microscopic structure of a crystalline material fluctuates in time. The results are just shed in Science Express with the title: Scaling in the Time Domain: Universal Dynamics of Order Fluctuations in Fe3Al.

The research team investigated a metal alloy, composed of iron and aluminium. When the structure of such a crystalline material changes upon heating, x-ray scientists can observe this by means of a diffraction experiment: One class of interference peaks associated with the low-temperature structure disappears, while another class of x-ray peaks belonging to the new structure may emerge. For a fixed temperature, however, the x-ray diffraction pattern has hitherto always been found to be static according to standard textbook wisdom. The novel observation is now that this x-ray diffraction pattern shows fluctuations in time when the beam is focused to a very small size of a few micrometers. This gives clearcut evidence that temporal structural fluctuations on an atomic scale are present in the crystal. By using a very small beam, the number of the temporal fluctuations "seen" by the x-ray beam is so small that these fluctuations now become visible as x-ray intensity fluctuations.

This discovery helps to shed light on a very fundamental aspect in the theory of condensed matter, namely to understand and predict how a given material reacts upon external perturbations like changes in temperature, pressure, magnetic or electric fields. Solid state theorists predicted a long time ago that the way that a material responds to these changes of external conditions is governed by these temporal fluctuations in the system. For the iron-aluminium alloy that was studied, these experimental results can be used for a test of the existence of universal, materials-independent laws in the dynamics of microscopic fluctuations.

Living metals

The figure shows the experiment schematically. A parallel beam is focused in a very thin area of the sample. Due to fluctuations in the material, the intensity of the diffracted x-ray beam fluctuates in time. The experiment was carried out on the ID22 beamline of the ESRF using a focused beam of 2x2 µm2 and probing a sample volume of 2x2x2 µm3. This challenging experiment became feasible thanks to the highly stable beam of the ESRF, the advances in sample preparation which allowed scientists to obtain very small sample volume and the accurately controlled experimental conditions (temperature, purity of the sample).

Source: European Synchrotron Radiation Facility

Explore further: Ultrafast imaging of complex systems in 3D at near atomic resolution nears

add to favorites email to friend print save as pdf

Related Stories

People finding their 'waze' to once-hidden streets

9 hours ago

When the people whose houses hug the narrow warren of streets paralleling the busiest urban freeway in America began to see bumper-to-bumper traffic crawling by their homes a year or so ago, they were baffled.

Identity theft victims face months of hassle

9 hours ago

As soon as Mark Kim found out his personal information was compromised in a data breach at Target last year, the 36-year-old tech worker signed up for the retailer's free credit monitoring offer so he would ...

Observers slam 'lackluster' Lima climate deal

9 hours ago

A carbon-curbing deal struck in Lima on Sunday was a watered-down compromise where national intransigence threatened the goal of a pact to save Earth's climate system, green groups said.

Your info has been hacked. Now what do you do?

9 hours ago

Criminals stole personal information from tens of millions of Americans in data breaches this past year. Of those affected, one in three may become victims of identity theft, according to research firm Javelin. ...

New Bond script stolen in Sony hack

9 hours ago

An "early version" of the screenplay for the new James Bond film was the latest victim of a massive hacking attack on Sony Pictures Entertainment, its producers said in a statement on their website Sunday.

Ag-tech could change how the world eats

14 hours ago

Investors and entrepreneurs behind some of the world's newest industries have started to put their money and tech talents into farming - the world's oldest industry - with an audacious agenda: to make sure there is enough ...

Recommended for you

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.