Four-State Straintronics: Extremely Low Power Nanomagnetic Logic Using Multiferroics With Biaxial Anisotropy

The authors had previously theoretically demonstrated that multiferroic nanomagnetic logic can be clocked in ∼1 GHz with few 100 kT/bit power dissipation which is ∼3 orders of magnitude more energy efficient than current CMOS transistor technology that dissipates several 100,000 kT/bit.. In this work, we propose the more novel concept of 4-state logic by numerically demonstrating the feasibity of an ultra low-power 4-state NOR logic gate using multiferroic nanomagnets with biaxial magnetocrystalline anisotropy. Here, the logic bits are encoded in the magnetization orientation of a nanoscale magnetostrictive layer elastically coupled to a piezoelectric layer. The piezoelectric layer can be clocked with a small electrostatic potential (∼0.2 V) to switch the magnetization of the magnetic layer. We also address logic propagation, where the accurate and unidirectional transfer of data from an input nanomagnet along an array of nanomagnets is needed. This is accomplished by devising an effective clocking scheme to the nanomagnet array, which allows for the realization of feasible logic circuits. Ultimately, this technology would enable higher order information processing, such as pattern recognition, to be performed in parallel at very high speeds while consuming extremely low power. Potential applications include high-density logic circuits, associative memory and neuromorphic computing.