TECHNOVA                                                       

New Magnetic Organic Molecules may Herald Malleable Computer Memory
by Shubham Agrawal
Birla Institute of Technology and Sciences, Pilani

Strong, flexible, lightweight and cheap, plastics have acquired an additional attribute in recent years: the ability to function as semiconductors, forming diodes and transistors in plastic integrated circuits. Now, as the first plastic electronics products are hitting the market in displays that use organic light-emitting diodes, the stage is set for a new era of pervasive computing with polymers. Plastics may never match the sheer processing speed and miniaturization of silicon, but they will be able to go places that silicon cannot reach: ultracheap radio-frequency identification tags; low-end, high-volume data storage; displays that are inexpensive, even disposable, or that can be wrapped around a wall column; and wearable computing. Other uses for conductive plastics include photocells, chemical sensors and pressure-sensitive materials  

A new family of magnetic molecules may point the way to computer memory that can be bent and flexed like plastic 

A group has synthesized three carbon-based (organic) nickel compounds that become magnetic spontaneously at room temperature--an extremely rare find. If researchers can figure out how these materials form and how to control that process, they might be able to turn similar compounds into pliable magnetic plastics.

Past examples of magnetic organic materials were either unstable in air or were mostly made of metal, making them unsuitable for linking together into a plastic, says chemist Robin Hicks of the University of Victoria, British Columbia.

the new molecules themselves could not be formed into plastics because they clump into loose powders that do not dissolve. But Hicks says that finding three related molecules suggests there are many others waiting to be found. "We have the ability in principle to change in relatively subtle ways the structure of the organic," he says, such as to make it more soluble.

The discovery was partly accidental. The researchers were mixing organic nitrogen-rich compounds with nickel atoms and water. Normally during such reactions, multiple organic molecules will attach to each metal ion, so a relatively small amount of nickel should have been needed. But Hicks says his postdoc, Rajsapan Jain, noticed that the chemicals were not completely used up in the reaction, so they kept adding nickel to see what would happen. They ended up with a mudlike powder in their test tubes.

The group seems to have discovered an entirely new route to magnetic molecules, says experimental physicist Christopher Landee of Clark University, who was not part of the study.

Although Hicks's team could not determine the exact structure of the molecules or how they formed, they found that, in this case, each organic molecule ended up with two nickels. Hicks says the magnetism probably stems from one lone (unpaired) electron on the nickel ion, which would therefore be positively charged, and another on the organic molecule, giving it a negative charge.

To be magnetic a molecule has to have isolated electrons, which act like tiny bar magnets. Normally electrons pair up and cancel out each other's magnetism, but Hicks says the organic molecules used in the experiment were selected because they can tolerate extra electrons.

"It's the first big step forward in 10 years, and that's what's encouraging about it," says Landee. "There will be a lot of chemists going back into the lab."

Long-awaited discovery of stable organic molecules that magnetize at room temperature

A key advantage of organic transistors over silicon is their ease of fabrication. Building a state-of-the-art silicon chip takes weeks of work using complex and expensive processes such as photolithography and vacuum deposition, carried out under high temperatures in ultraclean rooms. In comparison, organic transistors can be made using faster, cheaper processes under less carefully controlled conditions. Finally, there is the promise of "roll-to-roll" fabrication similar to the continuous printing presses that revolutionized publishing.