Light-driven atomic rotations excite magnetic waves
Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how the ultrafast light-induced modulation of the atomic positions in a material can control its magnetization. An international research team led by Andrea Cavalleri from the Max Planck Institute for the Structure and Dynamics of Matter at CFEL in Hamburg used terahertz light pulses to excite pairs of lattice vibrations in a magnetic crystal. These short bursts of light caused the lattice ions to rotate around their equilibrium positions, acting as an ultrafast effective magnetic field on the electronic spins to coherently drive a magnetic wave. These findings represent an important hallmark on how light interacts with matter and establish a novel approach in the control of magnetization at terahertz speed, making the research potentially relevant for magnetic storage technologies.