Effect of current-induced magnetic field on magnetization dynamics in spin-torque nano-oscillator with point-contact geometry

We show micromagnetic simulation results for spin-torque nano-oscillator (STNO) with point-contact geometry. Numerical results obtained from three different models are compared in order to investigate the effect of current-induced Oersted field and non-uniform current distribution on the characteristics of STNO. It is found that the Oersted field and non-uniform current distribution affect the frequency and precession mode both qualitatively and quantitatively. An anisotropic emission of spin-waves is observed only when considering the Oersted field properly. Our results suggest that a realistic consideration of the current distribution and consequent Oersted field distribution is of critical important to design STNOs and to understand the characteristics of STNOs.

► Micromagnetic simulation for spin-torque nano-oscillator (STNO) with point-contact geometry. ► Three different models with different current distribution and with/without Oersted field considered. ► Precession frequency and precession mode as a function of the current are analyzed. ► An anisotropic emission of spin-wave is observed due to the symmetry-breaking by the current-induced Oersted field.