Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

What makes nanowires so attractive

14.07.2009
Chinese-German team clearly identifies semiconducting nanowires with intrinsic ferromagnetic characteristics / Publication comes out today in "Nature Nanotechnology"

For a Chinese-German research team the "force of attraction" of minute nanowires is not only based on their special scientific interests: Physicists of the Chinese University of Hongkong and the Friedrich Schiller University Jena were able to prove for the first time that cobalt doped nanowires made from zinc oxide have intrinsic ferromagnetic characteristics - and therefore in principle work like tiny bar magnets.

The scientists around Prof. Dr. Quan Li (Hong Kong) and Prof. Dr. Carsten Ronning (Jena) will publish the results of their research in the current online edition of the well renowned journal "Nature Nanotechnology".

For that Prof. Ronning and his Jena team used their know-how about the preparation of semiconductor nanostructures and their optical characteristics, and doped zinc oxide wires. These were then examined for their magnetic properties by the Chinese colleagues around Prof. Li - an acknowledged expert in the field of electron microscopy. The innovative combination of two analytical methods - transmission electron microscopy and electron magnetic chiral dichroism - is responsible for the surprising outcome. "We realized that cobalt doping gives intrinsic ferromagnetic properties while iron does not", comments Prof. Li. Further investigations must now clarify where these differences come from.

The production of magnetic semiconducting nanowires has so far been basic research, as Quan Li emphasizes. But medium term "we might be able to help push open the door to spintronics". "Spintronics" is a new field in semiconductor physics: While traditional semiconductor electronics is based on the electrons' electrical charge, spintronics additionally uses the spin, the angular momentum, of the electrons. "That momentum can occur in two directions resulting in a magnetic moment", explains Prof. Ronning.

This new development could bring real advantages: Common electronic components need 10.000 to 100.000 electrons for a single switching action. Semiconductor components switching only the spin of electrons need only one electron to transport the necessary information. "That means that spintronic semiconductors could switch much faster than common electronic components", says Quan Li. Furthermore they would need only a fraction of the energy.

The precondition for a further development of spintronics however is, that semiconductors with intrinsic ferromagnetic characteristics can be produced at all. Intense worldwide research has been conducted for about a decade - so far with moderate success: There has not been a method clearly proving intrinsic ferromagnetism so far. Thanks to the current results the physicists have taken the field an important step further.

The original publication Z. H. Zhang, Xuefeng Wang, J. B. Xu, S. Muller, C. Ronning & Quan Li. Evidence of intrinsic ferromagnetism in individual dilute magnetic semiconducting nanostructures can be found under: http://www.nature.com/doifinder/10.1038/nnano.2009.181

Contact:
Prof. Dr. Quan Li
Department of Physics, The Chinese University of Hong Kong
Phone: + (852) 2609 6323
Email: liquan[at]phy.cuhk.edu.hk
http://www.phy.cuhk.edu.hk/qli/
Prof. Dr. Carsten Ronning
Institute for Solid State Physics, Friedrich Schiller University Jena
Phone: + (49) 3641 947300
Email: carsten.ronning[at]uni-jena.de
http://www.nano.uni-jena.de/en

Dr. Ute Schönfelder | idw
Further information:
http://www.nano.uni-jena.de/en
http://www.phy.cuhk.edu.hk/qli/
http://www.nature.com/doifinder/10.1038/nnano.2009.181

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: LaserTAB: More efficient and precise contacts thanks to human-robot collaboration

At the productronica trade fair in Munich this November, the Fraunhofer Institute for Laser Technology ILT will be presenting Laser-Based Tape-Automated Bonding, LaserTAB for short. The experts from Aachen will be demonstrating how new battery cells and power electronics can be micro-welded more efficiently and precisely than ever before thanks to new optics and robot support.

Fraunhofer ILT from Aachen relies on a clever combination of robotics and a laser scanner with new optics as well as process monitoring, which it has developed...

Im Focus: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Fraunhofer ISE Pushes World Record for Multicrystalline Silicon Solar Cells to 22.3 Percent

25.09.2017 | Power and Electrical Engineering

Usher syndrome: Gene therapy restores hearing and balance

25.09.2017 | Health and Medicine

An international team of physicists a coherent amplification effect in laser excited dielectrics

25.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>