Physicists prove the existence of magnetically charged spin battery

March 12th, 2009 - 3:30 pm ICT by ANI  

Washington, March 12 (ANI): An International team of physicists has been able to prove the existence of a spin battery, a battery that is charged by applying a large magnetic field to nano-magnets in a device called a magnetic tunnel junction (MTJ).

Developed by researchers at the University of Miami and at the Universities of Tokyo and Tohoku, in Japan, the new technology is a step towards the creation of computer hard drives with no moving parts, which would be much faster, less expensive and use less energy than current ones.

The device, created by University of Miami Physicist Stewart E. Barnes, of the College of Arts and Sciences and his collaborators, can store energy in magnets rather than through chemical reactions.

Like a winding up toy car, the spin battery is wound up by applying a large magnetic field.

We had anticipated the effect, but the device produced a voltage over a hundred times too big and for tens of minutes, rather than for milliseconds as we had expected, Barnes said.

That this was counterintuitive is what lead to our theoretical understanding of what was really going on, he added.

The secret behind this technology is the use of nano-magnets to induce an electromotive force. It uses the same principles as those in a conventional battery, except in a more direct fashion.

The energy stored in a battery, be it in an iPod or an electric car, is in the form of chemical energy.

When something is turned on, there is a chemical reaction which occurs and produces an electric current.

The new technology converts the magnetic energy directly into electrical energy, without a chemical reaction.

The electrical current made in this process is called a spin polarized current and finds use in a new technology called spintronics.

The new discovery advances our understanding of the way magnets work and its immediate application is to use the MTJs as electronic elements which work in different ways to conventional transistors.

Although the actual device has a diameter about that of a human hair and cannot even light up an LED (light-emitting diode), the energy that might be stored in this way could potentially run a car for miles. (ANI)

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