Chaotic dynamics in spin torque nano oscillator driven by voltage feedback

• DOI: 10.48550/arxiv.2409.13220
• Publication Date: 2024-09-20
• Authors: Meenakshi Sravani; Swapnil Bhuktare
• Keywords: Dynamics

Non-linear dynamics, including auto-oscillations, chaotic and synchronization, are integral to physical biological applications can be excited in spintronic devices. In this study, we interested exploring the excitation of chaos using voltage feedback a spin torque nano oscillator Magnetic Tunnel Junction (MTJ). According Poincar\'e-Bendixson theorem, cannot arise two-dimensional system MTJ featuring two dynamic variables describing zenith azimuth angles magnetization. Hence, prefer as it creates multi-dimensional system, making interesting explore emergence such systems. Such is achieved by utilizing 3-terminal device consisting an with in-plane pinned layer (PL) out-of-plane free (FL) geometry. When DC current above critical threshold applied, FL's oscillating magnetization generates AC output through Magneto Resistance (TMR) effect. A fraction voltage, fed back after delay, modulates anisotropy via controlled magnetic (VCMA) effect, potentially driving precessional motion or dynamics death based on delay gain circuit. The observed regime has been studied evaluating Lyapunov exponent, bifurcation diagrams, Fourier spectral analysis reconstruction trajectory embedding phase space. find practical random number generators reservoir computing.