Hybrid Spintronics/CMOS Logic Circuits Using All-Optical-Enabled Magnetic Tunnel Junction

Abstract

Spintronics is one of the emerging fields for next-generation low power, high endurance, nonvolatile, and area efficient memory technology. Spin torque transfer (STT), spin orbit torque (SOT), and electric field assisted switching mechanisms have been used to switch magnetization in various spintronic devices. However, their operation speed is fundamentally limited by the spin precession time that typically ranges in 10-400 ps. Such a time constraint severely limits the possible operation of these devices in highspeed systems. Optical switching using ultrashort laser pulses, on the other hand, is able to achieve subpicosecond switching operation in magnetic tunnel junctions (MTJs). In this paper, all optically switched (AOS) MTJ has been used to design high speed and low power hybrid MTJ/CMOS based logic circuits such as AND/NAND, XOR/XNOR, and full adder. Owing to the ultra-fast switching operation of AOS-MTJ, the circuit level results show that the energy and speed of AOS-MTJ based logic circuits are improved by 85% and 97%, respectively, when compared to STT based circuits. In comparison to SOT based designs, the proposed logic circuits show 10% and 91% improvement in energy efficiency and speed, respectively.