Reversible vs. irreversible voltage manipulation of interfacial magnetic anisotropy in Pt/Co/oxide multilayers

TL;DR

This study investigates how electric fields can reversibly or irreversibly modify interfacial magnetic anisotropy in Pt/Co/oxide multilayers by controlling oxygen ion migration, revealing material-dependent effects.

Contribution

It demonstrates voltage-driven control of magnetic anisotropy in multilayers using solid electrolytes and explains the differences in reversibility based on ionic conduction properties.

Findings

Reversible voltage effects in Pt/Co/AlOx and Pt/Co/TbOx multilayers.

Irreversible voltage effect observed in Pt/Co/MgOx multilayers.

Oxygen ion migration governs the magnetic anisotropy modification.

Abstract

The perpendicular magnetic anisotropy at the Co/oxide interface in Pt/Co/MOx (MOx = MgOx, AlOx, TbOx) was modified by an electric field using a 10 nm-thick ZrO2 as a solid electrolyte. The large voltage-driven modification of interfacial magnetic anisotropy and the non-volatility of the effect is explained in terms of the migration of oxygen ions towards/away from the Co/MOx interface. While the effect is reversible in Pt/Co/AlOx and Pt/Co/TbOx, where the Co layer can be oxidised or reduced, in Pt/Co/MgOx the effect has been found to be irreversible. We propose that these differences may be related to the different nature of the ionic conduction within the MOx layers.