In this case, the new alloy — Ni45Co5Mn40Sn10 — undergoes a reversible phase transformation, in which one type of solid turns into another type of solid when the temperature changes, according to a news release from the University of Minnesota. Specifically, the alloy goes from being non-magnetic to highly magnetized. The temperature only needs to be raised a small amount for this to happen.
When the warmed alloy is placed near a permanent magnet, like a rare-earth magnet, the alloy’s magnetic force increases suddenly and dramatically. This produces a current in a surrounding coil, according to the researchers, led by aerospace engineering professor Richard James.
One possible application for this alloy is in automobile exhaust pipes, which vent a lot of heat that could be recycled into electric power for the battery. Read more at Popsci. http://www.popsci.com/technology/article/2011-06/new-alloy-can-convert-heat-directly-electricity -via reddit