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Week 4/2010: Memory without electricity

Why do the physical characteristics of matter change when it is moulded into thin films or minuscule clusters? This is a hot research topic in modern physics.

An interesting example of this phenomenon is amorphisation, the loss of crystal structure. When embedded in an amorphic matrix, nanoparticles lose their crystal structure more easily than do larger pieces of matter. According to research conducted by Tommi Järvi, nanoparticles can be amorphisised more effortlessly, even without the amorphic matrix.

Industry is interested in amorphisation because the electrical conductivity of matter decreases considerably after the crystal structure disintegrates.

“Transforming nanoparticles from crystalline to amorphic, and vice versa, may well be the most promising method to produce flash-type memories that can retain the stored information without electricity,” Järvi says, describing applications under development around the world.

In his doctoral thesis, completed in November 2009, Järvi showed how crystal structures can be disintegrated using radiation, even in compounds that cannot otherwise be amorphisised. In his research, this applied to nanoparticles made of a mixture of iron and platinum.

Using a number of methods, Järvi has studied how nanoparticles react to ionic radiation. Ionic bombardment can be used to, for example, control the epitaxiality of nanoparticles; in other words, to align the crystalline structure of nanoclusters with that of the underlying surface. This improves the durability and electrical conductivity of metallic thin films.

Järvi is currently working as a postdoctoral researcher at the Fraunhofer Institute for Manufacturing Technology and Applied Materials Research in Germany. He says that it is too early to even guess at all the practical applications of nanotechnology. Scientists have only scratched the surface of the opportunities in thin films, to name just one example.

Text: Kimmo Luukkonen
Translation: AAC Global
Photo: Wikipedia/ Alchemist-hp (http://www.pse-mendelejew.de/) Richard Bartz

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