Featured Research

from universities, journals, and other organizations

Big success with tiny crystals

Date:
December 7, 2011
Source:
Vienna University of Technology, TU Vienna
Summary:
A little piece of iron wire is magnetic – just like a huge iron rod. When it comes to material properties, size usually does not matter. Surprisingly, researchers from Austria and India have now discovered that some materials show very unusual behavior, when they are studied in the form of tiny crystals. This could now lead to new materials with tailor-made electronic and magnetic properties.

Magnetism - large and small.
Credit: Image courtesy of Vienna University of Technology, TU Vienna

Tiny crystals exhibit unexpected properties. Researchers from the Vienna University of Technology and the University of Calcutta can now explain why.

A little piece of iron wire is magnetic -- just like a huge iron rod. When it comes to material properties, size usually does not matter. Surprisingly, researchers from Austria and India have now discovered that some materials show very unusual behavior, when they are studied in the form of tiny crystals. This could now lead to new materials with tailor-made electronic and magnetic properties.

Different Size Changes Material Properties

Material properties such as electrical conductivity, magnetic properties or the melting point do not depend on an object's size and shape. "In India, however, an experiment recently showed that special manganese oxides -- so called manganites -- exhibit completely different properties, when their size is reduced to tiny grains," Karsten Held explains.

A team of scientists from the Vienna University of Technology (Austria) and the University of Calcutta (India) investigated this phenomenon -- and the new effect could be explained in computer simulations. In a crossover from large crystals to smaller crystals, the distribution of the electrons changes, and so does their energy. This, in turn, changes the electrical and magnetic properties of the crystal. "The phenomenon of quantum entanglement plays a very important role here," says Professor Karsten Held. "We cannot think of the electrons as classical particles, moving independently of each other, on well-separated paths. The electrons can only be described collectively." By changing their size, the properties of the manganite-crystals can now be harnessed. Larger crystals are insulators, and they are not magnetic. Tiny crystal pieces on the other hand turn out to be metallic ferromagnets.

Important for Industrial Applications

Phase transitions, at which important material properties change, play a major role in technological applications: "When data is read from a hard-drive with a reading head, a transition between a conducting and a non-conducting state is used," Karsten Held explains. Similar effects can be seen in manganite crystals: "We knew that magnetic properties of manganites depend on the temperature and the magnetic field," says Tanusri Saha-Dasgupta, a material scientist at the Univeristy of Calcutta. "But now we know that these transitions can also be controlled by altering the size of the crystals." By changing the granular size of the crystals, the scientists can influence the critical temperature and magnetic field strength, at which the phase transition takes place. For technological applications, this opens up exciting new possibilities.

Huge Computational Effort

The manganite crystals studied by the Austro-Indian research team are only some three to fifteen billionths of a meter wide -- but still they consist of hundreds or thousands of atoms. Simulating their behavior on a computer is therefore still a great challenge. "The quantum mechanical equations we are dealing with here can only be solved with extremely powerful computer clusters," says PhD-student Angelo Valli. "Fortunately, the computer cluster VSC at the Vienna University of Technology provides us with remarkable computing power."


Story Source:

The above story is based on materials provided by Vienna University of Technology, TU Vienna. Note: Materials may be edited for content and length.


Journal Reference:

  1. Das et al. Size Control of Charge-Orbital Order in Half-Doped Manganite La0.5Ca0.5MnO3. Phys. Rev. Lett., 107, 197202 (2011)

Cite This Page:

Vienna University of Technology, TU Vienna. "Big success with tiny crystals." ScienceDaily. ScienceDaily, 7 December 2011. <www.sciencedaily.com/releases/2011/11/111129091333.htm>.
Vienna University of Technology, TU Vienna. (2011, December 7). Big success with tiny crystals. ScienceDaily. Retrieved July 25, 2014 from www.sciencedaily.com/releases/2011/11/111129091333.htm
Vienna University of Technology, TU Vienna. "Big success with tiny crystals." ScienceDaily. www.sciencedaily.com/releases/2011/11/111129091333.htm (accessed July 25, 2014).

Share This




More Matter & Energy News

Friday, July 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

TSA Administrator on Politics and Flight Bans

TSA Administrator on Politics and Flight Bans

AP (July 24, 2014) TSA administrator, John Pistole's took part in the Aspen Security Forum 2014, where he answered questions on lifting of the ban on flights into Israel's Tel Aviv airport and whether politics played a role in lifting the ban. (July 24) Video provided by AP
Powered by NewsLook.com
Creative Makeovers for Ugly Cellphone Towers

Creative Makeovers for Ugly Cellphone Towers

AP (July 24, 2014) Mobile phone companies and communities across the country are going to new lengths to disguise those unsightly cellphone towers. From a church bell tower to a flagpole, even a pencil, some towers are trying to make a point. (July 24) Video provided by AP
Powered by NewsLook.com
Algonquin Power Goes Activist on Its Target Gas Natural

Algonquin Power Goes Activist on Its Target Gas Natural

TheStreet (July 23, 2014) When The Deal's Amanda Levin exclusively reported that Gas Natural had been talking to potential suitors, the Ohio company responded with a flat denial, claiming its board had not talked to anyone about a possible sale. Lo and behold, Canadian utility Algonquin Power and Utilities not only had approached the company, but it did it three times. Its last offer was for $13 per share as Gas Natural's was trading at a 60-day moving average of about $12.50 per share. Now Algonquin, which has a 4.9% stake in Gas Natural, has taken its case to shareholders, calling on them to back its proposals or, possibly, a change in the target's board. Video provided by TheStreet
Powered by NewsLook.com
Robot Parking Valet Creates Stress-Free Travel

Robot Parking Valet Creates Stress-Free Travel

AP (July 23, 2014) 'Ray' the robotic parking valet at Dusseldorf Airport in Germany lets travelers to avoid the hassle of finding a parking spot before heading to the check-in desk. (July 23) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

    Health News

      Environment News

        Technology News



          Save/Print:
          Share:

          Free Subscriptions


          Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

          Get Social & Mobile


          Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

          Have Feedback?


          Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
          Mobile: iPhone Android Web
          Follow: Facebook Twitter Google+
          Subscribe: RSS Feeds Email Newsletters
          Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins