The most basic elements of a logical computing system are switching devices that can be cascaded to process information. This requires a circuit structure mechanism through which the output of each switching device is used as the input to another switching device. The unique switching mechanisms that characterize spintronic and bio-inspired computing elements provide new opportunities and challenges for the development of computing systems. In particular, new mechanisms are required through which switching devices can modulate the switching behavior of other similar devices. However, it is important to eschew CMOS amplification and control circuits to maximally exploit emerging technologies and computing paradigms.
In this presentation, recent progress will be evaluated with an emphasis on computing element interconnection, and several novel techniques for integrating directly-cascaded spintronic and bio-inspired computing elements will be described. Spin-diode logic leverages magnetoresistive nanodevices controlled by magnetic fields, particularly with graphene nanoribbons through the all-carbon spin logic paradigm. Emitter-coupled spin-transistor logic (ECSTL) extends this concept to magnetoresistive transistors, enabling highly compact circuits. The complementary magnetic tunnel junction logic (CMAT) structure enables non-volatile computation, with charge pulses between logic gates enabling direct cascading. Lastly, bio-inspired stochastic circuits incorporate conflicting information to efficiently perform Bayesian inference.