Selective optical excitation of high and low-frequency oscillation modes in NiO using double pump optical pulses

Abstract

Antiferromagnetic materials have the potential to enable high-speed processing in spintronic devices within the terahertz range owing to their ultrafast spin dynamics. NiO has attracted significant attention due to its Néel temperature being above room temperature in recent years. However, separating its two resonance modes remains a critical challenge, which is expected to be achieved by optical excitation. Micromagnetic simulations reveal that selective excitation of NiO resonance modes can be controlled via the polarization and time interval of the double pump optical pulse. The two oscillation modes can be probed by measuring the charge current components along different NiO/Pt heterostructure axes with the inverse spin Hall effect. This work unravels the physical conditions for the excitation of individual resonance modes in NiO, laying the foundation for the development of ultrafast opto-spintronic devices based on antiferromagnetic materials.