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The Sciences

Superconductors + Flux Tubes = Levitating Frozen Puck

80beatsBy Veronique GreenwoodOctober 20, 2011 8:21 PM


Sign up for our email newsletter for the latest science news When you freeze a chunk of sapphire coated in yttrium barium copper oxide, what do you get? A puck that can whiz around a magnetic track like a hovercraft. When the oxide gets very cold, it becomes a superconductor and actively repels magnets, with the result that when it's placed over a large enough magnet, it levitates. As the Tel Aviv University team behind this video explains, despite the puck's aversion to magnetic fields, the thinness of the oxide layer on it means that the field does manage to penetrate it a little. But only in tiny columns called flux tubes. The puck doesn't like having those flux tubes moved around in it, which happens whenever it moves. And in order to minimize the shifting of the flux tubes, it...floats. It's a phenomenon called quantum locking. No alien tech or magic required. We do wonder, though, if the levitating puck has ever met the levitating frog, pictured below. Or his buddy, the levitating (heavily sedated) mouse.

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