Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

The dance of crystal structures

10.11.2004


The word “crystal” is a technical term; iron and steel, for example, are crystals whereas glass is not. In fact, "crystal" means materials of a crystalline structure.



Just like any other kind of material, crystals can change their structure. For example, if the temperature rises sufficiently, it passes from a solid to a liquid state. But other, not so noticeable, structural changes also take place, such as those that occur in the solid state, itself. These changes are known as solid-to-solid phase transitions and are induced by changes in either temperature or pressure. Moreover, the electrical and magnetic properties of the crystals are affected during these transitions and are, thereby, of great interest for technology.

At the Leioa (Bizkaia) campus of the University of the Basque Country (EHU), a research team has been analysing solid-to-solid transitions of crystals. They selected a group of crystals known as double perovskites for this purpose. Prior to the analysis a certain amount of preparation work is required in the lab: the perovskites have to be synthesised.


Synthesis of crystals in the laboratory

The synthesis of crystals in the laboratory is not a simple process. First, the component powders of the crystal have to be mixed and compacted and then they have to be stabilised in the kiln. For example, to mention one method of synthesis, in order to obtain the Sr2NiWO6 perovskite, SrCO3, NiO and WO3 powders have to be blended. The result of the blend will also be a powder - perovskite powder.

But the resulting perovskite is not always the desired one and this is why it is necessary to characterise the compound obtained once it has been synthesised. That is, in this example, it has to be confirmed that it is, in fact Sr2NiWO6 perovskite and not another one, or, at least the same perovskite but with a few impurities.

Finally, once the desired perovskite has been obtained, various techniques are applied: X-ray diffraction, neutron diffraction, synchrotron radiation, Raman spectroscopy, etc. With all these, information about the crystal structure is obtained - location of the elements, their vibration frequency and a number of other properties. In order to carry this out, moreover, researchers have to travel to France and the United States, given that, in the University of the Basque Country, there is no synchotron; neither can Raman spectroscopy be carried out.

Solid structure is adaptable

So, the solid structure of the crystal is adaptable. But how? For example, when pressure increases, the structure of the crystal compacts so crystal atoms are nearer to each other. This may produce an increase in the vibration frequency of these atoms. At some point, the stability of the structure will break and change the location of components, thus, a solid-to-solid phase transition will have taken place.

Must be remenbered that these transitions are often accompanied by changes in the electrical and magnetic properties of the crystals: for example, the conductivity of the crystal can change when it reaches a certain temperature. The work at Leioa is targeting those values of temperature and pressure accompanied by transitions in the perovskites.

Garazi Andonegi | alfa
Further information:
http://www.elhuyar.com
http://www.basqueresearch.com

More articles from Physics and Astronomy:

nachricht Astronomers release most complete ultraviolet-light survey of nearby galaxies
18.05.2018 | NASA/Goddard Space Flight Center

nachricht A quantum entanglement between two physically separated ultra-cold atomic clouds
17.05.2018 | University of the Basque Country

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: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

Im Focus: Dozens of binaries from Milky Way's globular clusters could be detectable by LISA

Next-generation gravitational wave detector in space will complement LIGO on Earth

The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...

Im Focus: Entangled atoms shine in unison

A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.

The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...

Im Focus: Computer-Designed Customized Regenerative Heart Valves

Cardiovascular tissue engineering aims to treat heart disease with prostheses that grow and regenerate. Now, researchers from the University of Zurich, the Technical University Eindhoven and the Charité Berlin have successfully implanted regenerative heart valves, designed with the aid of computer simulations, into sheep for the first time.

Producing living tissue or organs based on human cells is one of the main research fields in regenerative medicine. Tissue engineering, which involves growing...

Im Focus: Light-induced superconductivity under high pressure

A team of scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg investigated optically-induced superconductivity in the alkali-doped fulleride K3C60under high external pressures. This study allowed, on one hand, to uniquely assess the nature of the transient state as a superconducting phase. In addition, it unveiled the possibility to induce superconductivity in K3C60 at temperatures far above the -170 degrees Celsius hypothesized previously, and rather all the way to room temperature. The paper by Cantaluppi et al has been published in Nature Physics.

Unlike ordinary metals, superconductors have the unique capability of transporting electrical currents without any loss. Nowadays, their technological...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

 
Latest News

Supersonic waves may help electronics beat the heat

18.05.2018 | Power and Electrical Engineering

Keeping a Close Eye on Ice Loss

18.05.2018 | Information Technology

CrowdWater: An App for Flood Research

18.05.2018 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>