11-11/12 :: November/December 2011

nanotimes News in Brief

plains. Similar effects can be seen in manganite cry- stals: “We knew that magnetic properties of manga- nites 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 in- fluence the critical temperature and magnetic field strength, at which the phase transition takes place. For technological applications, this opens up exci- ting new possibilities.

Hena Das, G. Sangiovanni, A. Valli, K. Held, and T. Sa- ha-Dasgupta: Size Control of Charge-Orbital Order in Half-Doped Manganite La0.5Ca0.5MnO3, In: Physical Review Letters, Vol. 107(2011), Article 197202 [5 pages], DOI:10.1103/PhysRevLett.107.197202: http://dx.doi.org/10.1103/PhysRevLett.107.197202

The Monami-Project: http://www.iacs.res.in/monami/Home.html

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“To construct some sort of nanoscale device com- prised of molecules, one needs to understand how those molecules will interact with one another.

“Typically, a useful device would be one in which the molecules arrange themselves in some perfectly ordered, regular manner. What we have studied here is almost the complete opposite – we have purposely tried to make the assemblies of molecules as random as possible.

“However, if we can gain a complete understanding of how randomness and disorder arises in these types of molecular structures, we can better under- stand how to eradicate that disorder when we want to create something functional.”

http://www.nottingham.ac.uk/physics/index.aspx

Scientists at The University of Nottingham have discovered a way to control how tiny flat mole- cules fit together in a seemingly random pattern. The researchers have been studying molecules which resemble tiny rhombus/diamond shaped tiles, with a side length of around 2nm. The fundamental research has shown that they can prompt the ‘tiles’ to form a range of random patterns by adjusting the conditions in which the experiment is con- ducted. Lead author Dr. Andrew Stannard, in the University’s School of Physics and Astronomy said:

Zhen Xu & Chao Gao at Zhejiang University, China, report that “soluble, chemically oxidized graphene or graphene oxide sheets can form chiral liquid crystals in a twist-grain-boundary phase-like model with simultaneous lamellar ordering and long-range helical frustrations. Aqueous graphene oxide liquid crystals were continuously spun into metres of macroscopic graphene oxide fibres.” © Nature

Zhen Xu, Chao Gao: Graphene chiral liquid crystals and macroscopic assembled fibres, In: Nature Communica- tions, Vol. 2(2011), December 06, 2011, Article number: 571, DOI:10.1038/ncomms1583: http://dx.doi.org/10.1038/ncomms1583