Magneto-ionic Control of Interfacial Magnetism

TL;DR

This paper demonstrates voltage-controlled manipulation of interfacial magnetism in metal/oxide heterostructures via in situ oxygen ion migration, enabling reversible and efficient magnetic property patterning for potential solid-state device applications.

Contribution

It introduces the first direct observation of voltage-driven oxygen ion migration in a Co/metal-oxide bilayer to control magnetic anisotropy, surpassing conventional magnetoelectric methods.

Findings

Voltage-driven oxygen ion migration toggles magnetic anisotropy.

Reversible patterning of magnetic properties achieved.

Enhanced switching efficiency through thermal activation.

Abstract

In metal/oxide heterostructures, rich chemical, electronic, magnetic and mechanical properties can emerge from interfacial chemistry and structure. The possibility to dynamically control interface characteristics with an electric field paves the way towards voltage control of these properties in solid-state devices. Here we show that electrical switching of the interfacial oxidation state allows for voltage control of magnetic properties to an extent never before achieved through conventional magnetoelectric coupling mechanisms. We directly observe, for the first time, in situ voltage driven O$^{2-}$ migration in a Co/metal-oxide bilayer, which we use to toggle the interfacial magnetic anisotropy energy by >0.6 erg/cm$^2$. We exploit the thermally-activated nature of ion migration to dramatically increase the switching efficiency and to demonstrate reversible patterning of magnetic properties through local activation of ionic migration. These results suggest a path towards voltage-programmable materials based on solid-state switching of interface oxygen chemistry.