The “spin Seebeck effect” is the rearrangement of the electrons according to their spins when one side of a magnetized nickel-iron rod is being heated. This “spin” effect is based on the original Seebeck effect, discovered in the 1800s by Johann Seebeck, which consists in the phenomenon of voltage apparition between two unequally-heated ends of a conducting rod. This is due to the electrons that move from the hot side to the cooler one.
Eiji Saitoh from the Keio University in Yokohama, Japan and other researchers have researched the spin Seebeck effect and published their findings in the journal Nature.
The spin Seebeck effect is similar to the original Seebeck effect, but it affects the electron spin, the quantum physics equivalent of north-south magnetic alignment. Eiji Saitoh experimented with a heated magnetized metal (nickel-iron), and found out that the electrons with up spins (aligned with the rod’s magnetic field) created an agglomeration on the hot side, while the ones with down spins (unaligned to the rod’s magnetic field), created an agglomeration on the cooler side.
The work is by now purely experimental, and this “magnetic battery” produces a “spin voltage”. This discovery can offer a ground for other devices that could use this effect, such as information storage systems, where the magnetic storage of information would be preferred because there isn’t any energy lost in form of heat, because all electrons are aligned and the thermal noise would be much less. This would allow for much smaller computer chips, which in effect could reduce the power consumption and raise the speed.
“The spin Seebeck effect allows us to pass a pure spin current, a flow of electron spins without electric currents, over a long distance,” the authors wrote in their study. “These innovative capabilities will invigorate spintronics research.”