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.