[Very difficult] Chua's circuit (chaos circuit)

[pgboswell]

Here’s a challenge from Steve Mould: Can you design a spintronic equivalent of Chua’s circuit?

Chua’s circuit is a cool little circuit designed fairly recently, in 1983. It’s the simplest circuit that generates chaos. It oscillates, but not at a defined frequency. In fact, it’s just the opposite: It’s a nonperiodic oscillator.

As you can see from the Wikipedia article, the only unusual part it needs is a nonlinear element (N_R in the image above). Well, as you might have noticed, our transistor isn’t particularly linear. That is, the resistance of the path isn’t directly proportional to the voltage applied to the gate.

So the challenge is this: can you make the spintronic equivalent of Chua’s circuit OR can you make any sort of other nonperiodic oscillator?

[dther]

I think (?) this is Chua’s circuit? Spintronics Simulator

I don’t understand electronics nearly well enough to explain this properly, but from my understanding, the negative resistive element (R) can be simulated by the battery+transistor+junction construction towards the top: as positive voltage increases, the gate is more open, allowing more current from the battery to flow, but because it’s driven through the middle sprocket, the battery actually produces negative voltage, decreasing the current. The nonlinear element is a transistor negatively coupled to its own base, such that as voltage increases, resistance increases, resulting in non-linear negative resistance.