ABSTRACT
This chapter provides an overview of extremely energy-efficient multiferroic nanomagnetic switches, comprising piezoelectric and magnetostrictive layers. Dipole coupling between such Bennett-clocked nanomagnetic switches was also shown to propagate information unidirectionally along a chain while dissipating a few 100 kT/bit at a ~1 GHz clock rate. The piezoelectric layer (PZT) of the multiferroic nanomagnet was 40 nm thick and the magnetostrictive layer (Terfenol-D) was 6 nm thick. Bennett clocking was implemented by applying tiny rectangular voltage pulses of ~15 mV amplitude across the piezoelectric layer of the multiferroic nanomagnet that generated strain and rotated the magnetization of the magnetostrictive layer by ~90°. Transistors switch by moving electrical charge into or out of their active regions. Neuromorphic hardware implemented with transistors and other charge-based devices like memristors have been stymied by the difficulty of implementing synapses with low power consumption.
