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.2009.181Contact:
Dr. Ute Schönfelder | idw
Astronomers release most complete ultraviolet-light survey of nearby galaxies
18.05.2018 | NASA/Goddard Space Flight Center
A quantum entanglement between two physically separated ultra-cold atomic clouds
17.05.2018 | University of the Basque Country
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...
The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...
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...
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...
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...
02.05.2018 | Event News
13.04.2018 | Event News
12.04.2018 | Event News
18.05.2018 | Power and Electrical Engineering
18.05.2018 | Information Technology
18.05.2018 | Information Technology