Ultrafast antiferromagnetic domain switching in NiO induced by spin transfer torques.

NiO is a prototypical antiferromagnet with a characteristic resonance frequency in the THz range. Using the spin transfer torque mechanism, we describe antiferromagnetic switching at this frequency, thus opening the possibility to speed up current logic of electronic devices by several orders of magnitude. We use atomistic spin dynamics simulations taking into account the crystallographic structure of NiO and in particular using a magnetic anisotropy respecting its symmetry. Sub-picosecond S-domain switching between the six allowed stable spin directions is found for reasonably achievable spin currents. We thus describe a simple procedure for picosecond writing of a six state memory and comment on the consequences for a possible NiO based antiferromagnetic oscillator.