An efficient and green way to convert heat into electricity

A recent discovery could help scientists to develop more efficient ways to generate electricity from heat that would have been otherwise wasted, such as heat coming from car exhaust, industrial processes, and interplanetary space probes.

In principle, magnetic fields can be used to generate electricity. If we move a magnet through a coil or wire, the magnet pushes and pulls electrons that create an electrical current. Magnets themselves don’t have energy, but they can control energy currents through the created magnetic field.

The main problem with magnets is that when a magnet is heated up, it loses most of its magnetic properties and becomes a so-called paramagnet. Until this discovery, scientists believed that paramagnets couldn’t be used for generating electricity. In the new study, researchers found a way of designing thermoelectric semiconductors that can convert heat to electricity.

The tiny particles in paramagnets, so called paramagnons, ended up producing enough spin to push an electron, for only a billionth of a millionth of a second – apparently long enough to make paramagnets viable energy-harvesters. This breakthrough in the conventional understanding of magnetic properties could lead to more research into how magnets and energy interact to potentially facilitate electricity production from heat that is otherwise wasted and oftentimes harmful to the environment.