Nonlinear Dynamics of an Antiferromagnetic Spintronic Oscillator

We study nonlinear dynamics of the spintronic nanosized antiferromagnetic terahertz oscillator consisting of an antiferromagnetic layer with easy-plane anisotropy (hematite) and a normal-metal (platinum) layer. Normal oscillation frequencies, namely, ferromagnetic and antiferromagnetic (terahertz) ones, are found. Their dependence on the value of a static magnetic field parallel to the sample plane is obtained. An approximate mathematical model in the form of the equations for the Néel-vector rotation angle in the azimuthal plane is developed for describing the oscillator dynamics. The adjustment characteristic, i.e., the dependence of the antiferromagnetic-mode frequency on the value of the direct current flowing in the platinum layer is obtained.