Digital logic using 3-terminal spin transfer torque devices

TL;DR

This paper introduces a novel digital logic implementation using three-terminal spin transfer torque devices with magnetic tunnel junctions, enabling functionally complete logic with resistive states that retain their information without power.

Contribution

It demonstrates for the first time that three-terminal spin transfer torque devices can be used to create functionally complete digital logic circuits with resistive states.

Findings

Devices can implement AND, NAND, OR, NOR gates without external circuitry

Resistive states retain information when unpowered

Threshold logic enables cascading and clocking of devices

Abstract

We demonstrate for the first time that functionally complete digital logic can be created by using three terminal devices each consisting of a magnetic tunnel junction (MTJ) and spin transfer torque (STT) element with a shared free magnetic layer. Rather than the output of devices being high or low voltage levels, logical states are represented as output resistances which retain their state when unpowered. By cascading and clocking devices using a multi-phase clock, threshold logic can be used to implement functionally complete digital logic. Using this approach, a single device can act as an AND, NAND, OR, or NOR gate without the need for external circuitry. Required device parameters and tolerances are discussed.