When an electric current flows in a material, the coupling of the electrons’ spin and orbital angular momentum causes spin-up electrons to bend in one direction and spin-down electrons in the other, both transverse to the charge current. That phenomenon is known as the spin Hall effect (see Physics Today, February 2005, page 17). Eiji Saitoh (Tohoku University), Sadamichi Maekawa (now at the Japan Atomic Energy Agency), and their colleagues have used that effect and its inverse—the creation of a charge current from a transverse spin current—as the basis for a counterintuitive demonstration: the transmission of a DC electrical signal a macroscopic distance through an insulator.
To read the rest of the article, click here.