Ultrafast antiferromagnetic switching in NiO induced by spin transfer torques
Théophile Chirac, Jean-Yves Chauleau, Pascal Thibaudeau, Olena Gomonay, M. Viret
Abstract
NiO is a prototypical antiferromagnet with a characteristic resonance frequency in the THz range. From atomistic spin dynamics simulations that take into account the crystallographic structure of NiO, and in particular a magnetic anisotropy respecting its symmetry, we describe antiferromagnetic switching at THz frequency by a spin transfer torque mechanism. Subpicosecond $S$-state switching between the six allowed stable spin directions is found for reasonably achievable spin currents, like those generated by laser induced ultrafast demagnetization. A simple procedure for picosecond writing of a six-state memory is described, thus opening the possibility to speed up current logic of electronic devices by several orders of magnitude.