Symmetry and the macroscopic dynamics of antiferromagnetic materials in the presence of spin-polarized current

Antiferromagnetic (AFM) materials with zero or vanishingly small macroscopic magnetization are nowadays the constituent elements of spintronic devices. However, the possibility to use them as active elements that show nontrivial and controllable magnetic dynamics is still discussible. In the present paper we extend the phenomenologic theory [Andreev and Marchenko, Sov. Phys. Usp. 23, 21 (1980)] of macroscopic dynamics in AFM materials for the cases typical for spin-valve devices. In particular, we consider the solidlike magnetic dynamics of AFM materials with strong exchange coupling in the presence of a spin-polarized current and give the general expression for the current-induced Rayleigh dissipation function in terms of the rotation vector for different types of AFMs. Based on the analysis of linearized equations of motion we predict the current-induced spin reorientation and AFM resonance, and find the values of critical currents in terms of AFMR frequencies and damping constants. The possibility of a current-induced spin-diode effect and second-harmonic generation in the AFM layer is also shown.