Department of Physics
Condensed Matter Seminar

Abstract: In conventional electronics, silicon chips process information by controlling the flow of charge through a network of gates, which is is then stored by encoding it in the orientation of magnetic domains of a computer hard disk. The key obstacle to a more intimate integration of magnetic materials into devices and circuit processing information is a lack of efficient means to control their magnetization. This is usually achieved with an external magnetic field or by the injection of spin-polarized currents. The latter can be significantly enhanced in materials whose ferromagnetic properties are mediated by charge carriers. Among these materials, conductors lacking spatial inversion symmetry couple charge currents to spin by intrinsic spin-orbit interactions, inducing nonequilibrium spin polarization. We show that magnetization of a ferromagnet can be reversibly manipulated by the spin-orbit-induced polarization of carrier spins generated by unpolarized currents. We demonstrate domain rotation and hysteretic switching of magnetization between two orthogonal easy axes in a model ferromagnetic semiconductor. Alexander Chernyshov, Mason Overby, Xinyu Liu, Jacek K Furdyna, Yuli Lyanda-Geller, and Leonid P. Rokhinson, Nature Physics Published online: 2 August 2009 | doi:10.1038/nphys1362