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Seminar | Materials Science Division

Spin-Orbit Torque: Using Relativity to Extract Angular Momentum from Crystals and Make New Quantum Devices

MSD Seminar

Abstract: Information and communications technology is predicted to account for 10-20% of the world’s electricity consumption within a decade. Alleviating this rise in power consumption requires rethinking the way we electronically process and store information. Spintronics, or spin electronics, offers a possible solution to this problem by using pure spin currents or spin waves rather than conventional charge currents to manipulate information. A key ingredient in spintronics is spin-orbit coupling: the relativistic coupling between a particle’s spin and orbital moments. Spin-orbit coupling permits conduction electrons to extract a virtually unlimited amount of angular momentum from the crystal lattice, potentially enabling energy efficient information processing.

In this talk, I will discuss the electrical manipulation of a ferromagnet’s magnetization through spin-orbit coupling. This phenomenon, known as spin-orbit torque, could help harness all the advantages of different electronic memories (e.g., speed, nonvolatility, radiation hardness) into one device. I will also discuss theoretical calculations and experimental evidence of novel spin current generation at material interfaces and in ferromagnets. These spin-orbit driven phenomena create exciting new possibilities for current-controlled magnetization dynamics with attractive applications for information processing.