Fig. 1. Chaotic attractor for Sprott-R system. (a) x-y; (b) x-z

Fig. 2. "8"type voltammetric characteristic curve of cubic magneto memristor

Fig. 3. Sprott-R chaotic system with memristor

Fig. 4. Chaotic attractor for system (7). (a) x-y; (b) x-z; (c) x-w; (d) y-z

Fig. 5. The Lyapunov exponential spectrum (a) and bifurcation diagram (b) of system (7) change with $a$ and $a\in [\mathrm{0.4,2.4}]$

Fig. 6. Projection of system (7) on x-y plane with $a$. (a) $a=\mathrm{0.45}$; (b) $a=\mathrm{1.15}$; (c) $a=\mathrm{1.45}$; (d) $a=\mathrm{1.75}$; (e) $a=\mathrm{2.1}$;(f) $a=\mathrm{2.25}$

Fig. 7. The Lyapunov exponential spectrum (a) and bifurcation diagram (b) of system (7) change with b and $b\in [\mathrm{0.1},\mathrm{2.1}]$

Fig. 8. Projection of system (7) on x-y plane with $b$. (a) $b=\mathrm{0.3}$; (b) $b=\mathrm{1.1}$; (c) $b=\mathrm{1.5}$

Fig. 9. Bifurcation diagram of the system with different parameters under different initial conditions (The red and blue lines represent the initial conditions $[-\mathrm{4},-\mathrm{2,3},\mathrm{4}]$ and $[-\mathrm{4},-\mathrm{2,8},\mathrm{4}]$. )

Fig. 10. Lyapunov exponential spectrum of system (7) with different initial conditions $[-\mathrm{4},-\mathrm{2,3},\mathrm{4}]$ (a) and $[-\mathrm{4},-\mathrm{2,8},\mathrm{4}]$ (b) ( L1, L2 respectively represent the two larger of the four Lyapunov indices and L1＞L2. )

Fig. 11. Projection on x-y plane of multiple coexisting attractors. (a) $a=\mathrm{0.41}$; (b) $a=\mathrm{0.9}$; (c) $a=\mathrm{2}$

Fig. 12. Projection (a) of Chaos attractor for system (7) and wave diagram (b) on x-y plane with $m$

Fig. 13. Four-dimensional output signal bifurcation diagram of system (7) with $m\in (\mathrm{10,60})$. (a) x-m; (b) y-m; (c) z-m; (d) w-m

Fig. 14. Projection (a) of system (7) and wave diagram (b) on x-y plane with $m>\mathrm{60}$

Fig. 15. Memristive chaotic system circuit diagram (a) and memristor's equivalent circuit (b)

Fig. 16. Circuit simulation results. (a) x-y; (b) x-z; (c) x-w; (d) y-z