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ePaper created 2012-09-28, 09:46:25 | version 1.24.0
2|2012 Research in Jülich Mixed-phase clouds – made up of ice crystals and droplets of water – are important for climate models. Their proper- ties are the focus of attention in the VerDI campaign (“Ver- tical Distribution of Ice in Arctic Clouds”). In April, the Po- lar 5 research aircraft set off for the Arctic from the Canadian town of Inuvik in a mission coordinated by the University of Leipzig. On board was the NIXE-CAPS spec- trometer, which researchers from Forschungszentrum Jü- lich use to study cloud particles. Clouds trap the thermal radiation of the earth in the at- mosphere, while also reflecting the incident radiation of the sun, thus cooling the earth. The intensity of these ef- fects in mixed-phase clouds depends above all on the frac- tion of ice particles they contain. And this is what NIXE- CAPS measures. Using a laser, it determines the size of each individual cloud particle, and it can also distinguish droplets of water from ice crystals. This allows conclusions to be drawn on how much ice is present in clouds. Flight into Icy Clouds NEWS IN BRIEF 5 How can computer data be reli- ably stored and read out in fu- ture when computers are get- ting smaller and smaller? Scientists from Jülich, Hamburg and Kiel propose to make use of magnetic moments in chains of iron atoms. This would allow information to be transported on the nanoscale in a fast and energy-efficient manner over a wide temperature range, while remaining largely unaffected by external magnetic fields. Computers currently save data in magnetic domains on the hard drive referred to as bits. However, if the bits lie too close together, their magnetic fields overlap, making the writing and reading of data impossible. In order to make new functionalities possible, computer components will have to shrink even more. “Spin spirals” could provide an alternative method of trans- porting data in the tiniest of dimensions and allow information to be compressed even further in the future. This is what the researchers call the spiral arrangement of the magnetic proper- ties (spins) in chains of iron atoms. If one end of such a chain is connected to a magnetized object, then its magnetic orienta- tion can be read out at the other end, a few atoms and up to three hundred thousandths of a millimetre (30 nanometres) fur- ther away. This type of information transmission can be com- pared to a screw: the iron atoms are the screw, the spin the thread. If you turn the screw head, the revolution proceeds right to the tip and the position of the screw head provides informa- tion about the position of the tip. :: Spin Spirals for Computers of the Future Prof. Christian Kumpf and his team conduct research on the potential of organic molecular layers at Jülich’s Peter Grünberg Institute. Organic semiconductors are becoming common com- ponents in smartphones and televisions, for example, as organic light-emitting diodes (OLEDs). Their advan- tages compared to conventional materials: they are cheap to produce, can be flexibly shaped and are rela- tively insensitive to external influences. In principle, they could even be simply printed on plastic foils in fu- ture. However, many basic properties of the new gen- eration of semiconductor electronics are not yet fully understood. Physicists at Jülich have now discovered an unexpectedly strong bond between the organic lay- ers that form the basis for the novel electronic compo- nents. This knowledge could help the efficiency of the organic semiconductors to be selectively increased. In the past, scientists assumed that organic mate- rials only interacted among each other via weak van der Waals forces. Only in contact with certain metals did they also exhibit stronger bonding referred to as chemisorption. For the first time, the Jülich research- ers have now also demonstrated such chemisorption between two organic layers applied to a silver crystal by chemical vapour deposition. Such sandwich-like structures are also found in OLEDs and usually consist of several organic layers between two metallic conduc- tors. The semiconductor interfaces are of particular in- terest to the research community because component performance depends on how well contacts can be created with other organic and metallic conductors. The stronger the bond, the better electrons can pass from one material to the other – and the more power or light can be produced by solar cells or light-emitting diodes. :: Strong Bonds