Spin waves carry energy from cold to hot

Heat normally flows from hot to cold, but now physicists in Japan and Germany have shown that spin waves can reverse the flow. The team fired microwaves at one end of a crystal, which instead of heating up, stayed cool. Meanwhile, some distance away at the other end of the crystal, the temperature rose – with heat being transported from the cool end to the hot end by spin waves. The team believes that the results could lead to the development of new devices that use heat and spin to store and process information.