"A computer hard disk reader that uses a GMR sensor is equivalent to a jet flying at a speed of 30,000 kilometers (19,500 miles) per hour ... at a height of just one meter above the ground, and yet being able to see and catalogue every single blade of grass it passes over," [Ben Murdin, a physics professor at the University of Surrey in southeast England] said.And sort of like a B-movie franchise, researchers keep uncovering new, more powerful forms of magnetoresistance: colossal magnetoresistance, ballistic magnetoresistance and (my personal favorite) extraordinary magnetoresistance, to name three. Mere giant magnetoresistance, which debuted in commercial hard drives back in 1998, represented the first example of so-called spintronics, or electronics based not on charge but spin, the property of an electron that makes it act like a tiny bar magnet. Physicists have started thinking that more exotic magnetic effects (like that spin Hall effect mentioned above) might allow them to build quantum computers that run on spin. This year's physics Nobel should remind us that the notion of uninterruptible technological progress embodied in Moore's law doesn't just happen by magic. It takes researchers like Fert and Gruenberg working today to keep those trends moving as each new decade rolls around. Related links: SciAm explained vertical hard drives in the August, 2006, installment of Working Knowledge (available for a fee) and looked at other efforts to push hard disk density in this 2005 profile, "Kryder's Law." Read more about the growing field of spintronics in last month's feature story, "The Diamond Age of Spintronics," and the 2002 feature, "Spintronics." In May I wrote about a way to control spin in silicon. And let's not forget the room temperature spin Hall effect.
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