New alloy can convert heat directly into electricity

A new alloy with unique properties can convert heat directly into electricity, according to researchers at the University of Minnesota. The alloy, a multiferroic composite of nickel, cobalt, manganese and tin, can be either non-magnetic and highly magnetic, depending on its temperature.

Multiferroic materials possess both magnetism and ferroelectricity, or a permanent electric polarization. Materials with both of these properties are very rare; check out this explainer from the National Institute of Standards and Technology if you’re interested in the electron orbital arrangements that cause these phenomena.

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. Watch a piece of the alloy leap over to a permanent magnet in the video clip below.


/Popular Science/