Researchers Create Battery-less Circuit

08/15/2011 |


Researchers in Virginia have created a circuit that uses so little energy that batteries are not even necessary.

A team from Virginia Commonwealth University has devised perhaps the world's most miserly integrated circuit. It could run merely by tapping the ambient energy from the environment.

The researchers created this circuit by combining two electron technologies: spintronics and straintronics.

 Rather than the traditional charge-based electronic switches that encode the basic 0s and 1s of computer lingo, spintronics harnesses the natural spin of electrons to store bits of data. Spin one way and you get a 0; switch the spin the other way and you get a 1. During switching, spintronics uses considerably less energy than charge-based electronics. However, when ramped up to usable processing speeds, much of that energy savings is lost in the mechanism through which the energy from the outside world is transferred to the magnet.

The solution is to use a special class of composite structure called multiferroics. These composite structures consist of a layer of material with close contact to a nonmagnet that changes shape in response to strain. When a tiny voltage is applied across the structure, it generates strain in one layer and is transferred to another layer. This strain rotates the direction of magnetism, achieving the flip.

With the proper choice of materials, the energy output can be as low as 0.4 attojoules, or about a billionth of a billionth of a joule. This proposed design would create an extremely low-power, yet high-density, non-volatile magnetic logic and memory system.

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