Abstract: The magnetization of a magnetic material can be reversed by electric currents that transport spin angular momentum. This was predicted in magnetic tunnel junctions — two metallic ferromagnetic layers separated by a thin insulating barrier — by John Slonczewski in 1989 and demonstrated experimentally about a decade later. This discovery has had an enormous impact on magnetism research and technology, as prior to this the primary means to reorient the magnetization of a magnet was by applying magnetic fields (dating to 1819 and Oersted!). In this talk I will highlight some of the physics and applications enabled by the discovery of spin-transfer torques. This includes experiments that explore the spin-torque switching mechanisms of perpendicularly magnetized magnetic tunnel junctions, the device used in spin-transfer torque magnetic random-access memories. I will also discuss spin torques associated with spin-orbit coupling in ferromagnetic metals. 

Bio: Andrew Kent is a Professor of Physics and Director of the Center for Quantum Phenomena at New York University. His research interests are in the physics of magnetic nanostructures, nanomagnetic devices and magnetic information storage.