Low-power Spin Valve Logic using Spin-transfer Torque with Automotion of Domain Walls

TL;DR

This paper introduces a low-power, non-volatile spin valve logic scheme using spin-transfer torque and domain wall automotion, enabling scalable, energy-efficient digital computation with improved electromigration resistance.

Contribution

It proposes a novel spin valve logic device utilizing domain wall automotion and optimized device sizing, demonstrating lower current operation and enhanced scalability over previous non-local spin valve schemes.

Findings

Simulated buffer, inverter, and majority gate demonstrate functionality.

Achieved lower current density operation compared to previous schemes.

Enhanced energy efficiency and electromigration resistance.

Abstract

A novel scheme for non-volatile digital computation is proposed using spin-transfer torque (STT) and automotion of magnetic domain walls (DWs). The basic computing element is composed of a lateral spin valve (SV) with two ferromagnetic (FM) wires served as interconnects, where DW automotion is used to propagate the information from one device to another. The non-reciprocity of both device and interconnect is realized by sizing different contact areas at the input and the output as well as enhancing the local damping mechanism. The proposed logic is suitable for scaling due to a high energy barrier provided by a long FM wire. Compared to the scheme based on non-local spin valves (NLSVs) in the previous proposal, the devices can be operated at lower current density due to utilizing all injected spins for local magnetization reversals, and thus improve both energy efficiency and resistance to electromigration. This device concept is justified by simulating a buffer, an inverter, and a 3-input majority gate with comprehensive numerical simulations, including spin transport through the FM/non-magnetic (NM) interfaces as well as the NM channel and stochastic magnetization dynamics inside FM wires. In addition to digital computing, the proposed framework can also be used as a transducer between DWs and spin currents for higher wiring flexibility in the interconnect network.