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Fresh Spin On Logic

MIT team paves way for a spintronics microprocessor

3 min read

In the last few years, a new type of memory has begun to penetrate the market for nonvolatile data storage. The devices exploit a fundamental yet abstract and elusive property of ­electrons called spin. Because it ­underlies permanent magnetism, spin can be thought of as analogous to ­rotation, with a kind of nanoworld angular momentum. An electron’s spin is proportional to its magnetic momentum, and so when spin-polarized electrical currents flow through different types of magnetized metal, resistance changes can be exploited to store information.

Even more interesting would be a microprocessor using spin. In principle, a device that encoded information using the orientation of electrons could handle data thousands of times as fast as the present-day processors that rely only on charge. ”Instead of an electron being there or not there in the gate of a transistor—basically two pieces of information—think about an electron being able to hold a million pieces of information,” says David Awschalom, a physicist at the University of California at Santa Barbara who specializes in the development of magnetic semiconductors. In addition to being much faster, spintronics processors could be much smaller than present-day processors.

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The Transistor at 75

The past, present, and future of the modern world’s most important invention

2 min read
A photo of a birthday cake with 75 written on it.
Lisa Sheehan

Seventy-five years is a long time. It’s so long that most of us don’t remember a time before the transistor, and long enough for many engineers to have devoted entire careers to its use and development. In honor of this most important of technological achievements, this issue’s package of articles explores the transistor’s historical journey and potential future.

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