Sub-picosecond magnetization reversal in fully ferromagnetic spin valves

The discovery of spin-transfer torque (STT) has paved the way for controlling the magnetization direction in magnetic devices within nanoseconds using an electrical current solely. However, current-induced STT switching below a few hundred picoseconds with low power consumption while maintaining high thermal stability is challenging. Ultra-short optical pulses can induce spin angular momentum transfer in a ferromagnetic spin valve, resulting in different demagnetization time depending on its magnetic configuration within less than a picosecond. However, magnetization reversal in ferromagnetic spin valves by a single femtosecond laser pulse has not been achieved. Here we demonstrate an optically induced sub-picosecond magnetization reversal in archetypical rare-earth-free spin valves of [Pt/Co]/Cu/[Co/Pt] that are used for current-induced STT switching. Our findings may provide a new route to ultrafast magnetization reversal by further bridging concepts from spintronics and ultrafast magnetism.