The December 2022 issue of IEEE Spectrum is here!

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Flash of Brilliance or Flash in the Pan?

Giant planar Hall effect could be the next big thing in data storage

3 min read

The sensitivity of read-heads and the capacity of hard disks could in principle be more than 1000 times greater as a result of a new effect discovered by researchers at the California Institute of Technology (Pasadena) and the University of California, Santa Barbara. Those researchers, though, are the first to caution that much depends on whether the effect can be effectively harnessed.

They detected what is now called the giant planar Hall effect in thin films of gallium manganese arsenide—one of a new class of materials, ferromagnetic semiconductors, whose magnetic and electronic properties are susceptible to control. Hong Tang of Caltech performed many of the measurements that demonstrated the effect, obtained by careful doping of gallium arsenide with atoms of manganese.

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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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