Electrical control of metallic heavy-metal/ferromagnet interfacial states

TL;DR

This paper demonstrates a novel method for electrically controlling metallic interfaces using ionic effects, enabling independent manipulation of magnetic properties and significantly improving spin torque efficiency.

Contribution

It introduces ionic-based voltage control in metallic systems, overcoming electron screening limitations and enabling tunable magnetic properties in Pt/Co interfaces.

Findings

Magnetization and magnetic anisotropy can be independently controlled.

Spin torque efficiency is increased by approximately 3.5 times.

Switching current is reduced by about an order of magnitude.

Abstract

Voltage control effects provide an energy-efficient means of tailoring material properties, especially in highly integrated nanoscale devices. However, only insulating and semiconducting systems can be controlled so far. In metallic systems, there is no electric field due to electron screening effects and thus no such control effect exists. Here we demonstrate that metallic systems can also be controlled electrically through ionic not electronic effects. In a Pt/Co structure, the control of the metallic Pt/Co interface can lead to unprecedented control effects on the magnetic properties of the entire structure. Consequently, the magnetization and perpendicular magnetic anisotropy of the Co layer can be independently manipulated to any desired state, the efficient spin toques can be enhanced about 3.5 times, and the switching current can be reduced about one order of magnitude. This ability to control a metallic system may be extended to control other physical phenomena.