This paper demonstrates the reversal of magnetization in bulk nickel using a single sub-picosecond laser pulse. Time-dependent electronic structure simulations reveal that ultrafast light-induced torques are the underlying mechanism, effective only with circularly polarized light on a plane containing the initial magnetization orientation. The study maps the laser pulse parameter space enabling magnetization switching and reveals rich intra-atomic orbital-dependent magnetization dynamics, including transient non-collinear states. These findings open avenues for efficient optically-based spintronic devices.

Hanan Hamamera, Filipe Souza Mendes Guimarães, Manuel dos Santos Dias, Samir Lounis