Chemistry Times
Recent News |  Archives |  Tags |  About |  Newsletter |  Submit News |  Links |  Subscribe to ChemistryTimes.com RSS Feed Subscribe


More Articles
Rediscovering Venus to find faraway earthsRediscovering Venus to find faraway earths

Archaeologists discover bronze remains of Iron Age chariotArchaeologists discover bronze remains of Iron Age chariot

Researchers resolve the Karakoram glacier anomaly, a cold case of climate scienceResearchers resolve the Karakoram glacier anomaly, a cold case of climate science

Fish tale: New study evaluates antibiotic content in farm-raised fishFish tale: New study evaluates antibiotic content in farm-raised fish

New 3-D display technology promises greater energy efficiencyNew 3-D display technology promises greater energy efficiency

Researchers break nano barrier to engineer the first protein microfiberResearchers break nano barrier to engineer the first protein microfiber

Structure of an iron-transport protein revealedStructure of an iron-transport protein revealed

First step: From human cells to tissue-engineered esophagusFirst step: From human cells to tissue-engineered esophagus

Magnetic mirrors enable new technologies by reflecting light in uncanny waysMagnetic mirrors enable new technologies by reflecting light in uncanny ways

Lift weights, improve your memoryLift weights, improve your memory

Spiders: Survival of the fittest groupSpiders: Survival of the fittest group

Autophagy helps fast track stem cell activationAutophagy helps fast track stem cell activation

Myelin vital for learning new practical skillsMyelin vital for learning new practical skills

More physical activity improved school performanceMore physical activity improved school performance

Engineering new vehicle powertrainsEngineering new vehicle powertrains

Around the world in 400,000 years: The journey of the red foxAround the world in 400,000 years: The journey of the red fox

Active aging is much more than exerciseActive aging is much more than exercise

Study: New device can slow, reverse heart failureStudy: New device can slow, reverse heart failure

Are the world's religions ready for ET?Are the world's religions ready for ET?

Gut bacteria, artificial sweeteners and glucose intoleranceGut bacteria, artificial sweeteners and glucose intolerance

Recreating the stripe patterns found in animals by engineering synthetic gene networksRecreating the stripe patterns found in animals by engineering synthetic gene networks

Laying the groundwork for data-driven scienceLaying the groundwork for data-driven science

Hold on, tiger momHold on, tiger mom

Nature's designs inspire research into new light-based technologiesNature's designs inspire research into new light-based technologies

Missing piece found to help solve concussion puzzleMissing piece found to help solve concussion puzzle

Biologists delay the aging process by 'remote control'Biologists delay the aging process by 'remote control'

Geography matters: Model predicts how local 'shocks' influence U.S. economyGeography matters: Model predicts how local 'shocks' influence U.S. economy

Identified for the first time what kind of explosive has been used after the detonationIdentified for the first time what kind of explosive has been used after the detonation

Copied from nature: Detecting software errors via genetic algorithmsCopied from nature: Detecting software errors via genetic algorithms

Creating electricity with caged atoms (10/2/2013)

Tags:
cerium, conductivity, electrons, elements, energy, gold, heat, materials, research, silicon, temperature, thermal conductivity, thermoelectric materials, thermoelectrics
Clathrates: Tiny cages enclosing single atoms are shown. -  TU Vienna
Clathrates: Tiny cages enclosing single atoms are shown. - TU Vienna

A lot of energy is wasted when machines turn hot, unnecessarily heating up their environment. Some of this thermal energy could be harvested using thermoelectric materials; they create electric current when they are used to bridge hot and cold objects. At the Vienna University of Technology (TU Vienna), a new and considerably more efficient class of thermoelectric materials can now be produced. It is the material's very special crystal structure that does the trick, in connection with an astonishing new physical effect; in countless tiny cages within the crystal, cerium atoms are enclosed. These trapped magnetic atoms are constantly rattling the bars of their cage, and this rattling seems to be responsible for the material's exceptionally favourable properties.

Cerium Cages from the Mirror Oven

"Clathrates" is the technical term for crystals, in which host atoms are enclosed in cage-like spaces. "These clathrates show remarkable thermal properties", says Professor Silke Bühler-Paschen (TU Vienna). The exact behaviour of the material depends on the interaction between the trapped atoms and the cage surrounding them. "We came up with the idea to trap cerium atoms, because their magnetic properties promised particularly interesting kinds of interaction", explains Bühler-Paschen.

For a long time, this task seemed impossible. All earlier attempts to incorporate magnetic atoms such as the rare-earth metal cerium into the clathrate structures failed. With the help of a sophisticated crystal growth technique in a mirror oven, Professor Andrey Prokofiev (TU Vienna) has now succeeded in creating clathrates made of barium, silicon and gold, encapsulating single cerium atoms.

Electricity from Temperature Differences

The thermoelectric properties of the novel material have been tested. Thermoelectrics work when they connect something hot with something cold: "The thermal motion of the electrons in the material depends on the temperature", explains Bühler-Paschen. "On the hot side, there is more thermal motion than on the cold side, so the electrons diffuse towards the colder region. Therefore, a voltage is created between the two sides of the thermoelectric material."

Experiments show that the cerium atoms increase the material's thermopower by 50%, so a much higher voltage can be obtained. Furthermore, the thermal conductivity of clathrates is very low. This is also important, because otherwise the temperatures on either side would equilibrate, and no voltage would remain.

The World's Hottest Kondo Effect

"The reason for these remarkably good material properties seem to lie in a special kind of electron-electron correlation - the so-called Kondo effect", Silke Bühler-Paschen believes. The electrons of the cerium atom are quantum mechanically linked to the atoms of the crystal. Actually, the Kondo effect is known from low temperature physics, close to absolute zero temperature. But surprisingly, these quantum mechanical correlations also play an important role in the novel clathrate materials, even at a temperature of hundreds of degrees Celcius.

"The rattling of the trapped cerium atoms becomes stronger as the temperature increases", says Bühler-Paschen. "This rattling stabilizes the Kondo effect at high temperatures. We are observing the world's hottest Kondo effect."

More Research for Better and Cheaper Clathrates

The research team at TU Vienna will now try to achieve this effect also with different kinds of clathrates. In order to make the material commercially more attractive, the expensive gold could possibly be substituted by other metals, such as copper. Instead of cerium, a cheaper mixture of several rare-earth elements could be used. There are high hopes that such designer clathrates can be technologically applied in the future, to turn industrial waste heat into valuable electrical energy.

Note: This story has been adapted from a news release issued by the Vienna University of Technology

Post Comments:

Search
New Articles
Novel 3D printing process enables metal additive manufacturing for consumer marketNovel 3D printing process enables metal additive manufacturing for consumer market

Can plants edge out petroleum as raw material for textiles and plastics?

ORNL thermomagnetic processing method provides path to new materialsORNL thermomagnetic processing method provides path to new materials

'Reverse engineering' materials for more efficient heating and cooling'Reverse engineering' materials for more efficient heating and cooling

Li-ion batteries contain toxic halogens, but environmentally friendly alternatives exist

Thermodiffusion in weightlessness

Watching the hidden life of materialsWatching the hidden life of materials

A GPS from the chemistry setA GPS from the chemistry set

Getting the salt out

Strengthening thin-film bonds with ultrafast data collectionStrengthening thin-film bonds with ultrafast data collection

Ph.D. designs new devices based on metamaterials

An effective, cost-saving way to detect natural gas pipeline leaks

Super stable garnet ceramics may be ideal for high-energy lithium batteriesSuper stable garnet ceramics may be ideal for high-energy lithium batteries

New insights on carbonic acid in waterNew insights on carbonic acid in water

Researchers reach 'paradigm shift' in understanding potassium channels



Archives
November 2014
October 2014
September 2014
August 2014
July 2014
June 2014
May 2014
April 2014
March 2014
February 2014
January 2014
December 2013
November 2013
October 2013
September 2013
August 2013
July 2013
June 2013
May 2013
April 2013
March 2013
February 2013
January 2013
December 2012
November 2012
October 2012
September 2012
August 2012
July 2012
June 2012
May 2012
April 2012
March 2012
February 2012
January 2012
December 2011
November 2011
October 2011
September 2011
August 2011
July 2011
June 2011
May 2011
April 2011
March 2011
February 2011
January 2011
December 2010
November 2010
October 2010
September 2010
August 2010
July 2010
June 2010
May 2010
April 2010
March 2010
February 2010
January 2010
December 2009
November 2009
October 2009
September 2009
August 2009
July 2009
June 2009
May 2009
April 2009
March 2009
February 2009
January 2009
December 2008
November 2008
October 2008
September 2008
August 2008
July 2008
June 2008
May 2008
April 2008
March 2008
February 2008
January 2008
December 2007
November 2007
October 2007
September 2007
August 2007


Science Friends
Agricultural Science
Astronomy News
Sports Tech
Biology News
Biomimicry Science
Cognitive Research
Tissue Engineering
Cancer Research
Cybernetics Research
Electonics Research
Forensics Report
Fossil News
Genetic Archaeology
Genetics News
Geology News
Microbiology Research
Nanotech News
Parenting News
Physics News


  Archives |  Submit News |  Advertise With Us |  Contact Us |  Links
Use of this site constitutes acceptance of our Terms of Service and Privacy Policy. All contents © 2000 - 2015 Web Doodle, LLC. All rights reserved.