Coherent control of antiferromagnetism in NiO

Coherent control of the antiferromagnetic (AFM) order parameter of NiO is achieved by sequences of optical pump pulses modifying the magnetic anisotropy. The modification allows reversible switching of the AFM order parameter between hard- and easy-axis states. The switching frequency is determined by the magnetic anisotropy only and can therefore be higher than in the case of ferromagnetic spin precession. For NiO frequencies up to 100 GHz are achieved. Possibilities for device application are discussed.