HP made headlines when it developed the memristor, a long-theorized, but never proven fourth electronic circuit element. Called by some the "holy grail" of electronics research, the element held great promise for creating cheaper, more efficient memory.
Since the development memristor research has boomed, and researchers with the National Institute of Standards and Technology now have reported an exciting development -- a flexible memristor. To develop it, research combined polymer sheets (similar chemically and physically to transparencies) and titanium dioxide (a common ingredient in sunscreen). Best of all, rather than using expensive deposition equipment for the titanium dioxide, an experimental sol gel process was used. Under this process, the material in liquid form is spun, then allowed to set into a solid, similar to Jell-O.
States NIST researcher Nadine Gergel-Hackett, "We wanted to make a flexible memory component that would advance the development and metrology of flexible electronics, while being economical enough for widespread use. Because the active component of our device can be fabricated from a liquid, there is the potential that in the future we can print the entire memory device as simply and inexpensively as we now print a slide on an overhead transparency."
Intriguingly, while the researchers did not set out to create a memristor, it appears they have created one. A memristor is technically a resistor that changes its resistance depending on the amount of current that is sent through it—and retains this resistance even after the power is turned off. It is considered a fourth circuit element in addition to resistors, capacitors, and inductors. The device indeed holds the properties of a memristor, and the team appears to have created the first flexible memristor.
The resulting memristor can run on only 10 volts and maintains memory even when powered off. It was flexed 4,000 times and still remained functionality.
The researchers now plan to fully explore the possibilities of the patent-pending technology. They hope to also find applications for the new technology, including memory for flexible MP3 players and for flexible medical sensors, such as heart rate or blood sugar monitors.
A paper on the research has been published in the journal IEEE Electron Device Letters.
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