Electrical Switching of Magnetization in Films of alpha-Iron with Naturally Hydroxidized Surface

TL;DR

This study demonstrates room-temperature electric-field-induced magnetization switching in alpha-iron films with a naturally hydroxidized surface, highlighting the role of the FeOOH layer in low-power magnetic control.

Contribution

It reveals a novel electric-field-driven magnetization switching mechanism in alpha-Fe films mediated by the FeOOH surface layer, without external magnetic fields.

Findings

Magnetization can be switched electrically at room temperature.

The electric field, not current, drives the switching.

FeOOH layer induces weak ferromagnetism affecting magnetization.

Abstract

Control of the magnetization vector in ferromagnetic films and heterostructures by using electric tools instead of external magnetic fields can lead to low-power memory devices. We observe the robust changes in magnetization states of a thin (about 30 nm) film of alpha-Fe covered by the naturally formed layer ( about 6 nm in thickness) of iron ohyhydroxides (FeOOH) under discharging a capacitor through the film. Strikingly, the magnetization vector is switchable by the discharge even with no any biasing field at room temperatures. In this electrically induced magnetization switching (EIMS) we reveal the key role of the FeOOH layer. We demonstrate experimental evidences that not the discharge current itself but the electric field (of the order of 10 kV/m) generated by this current is responsible for EIMS. The results reported here provide a plausible explanation of the observed phenomenon in terms of electric-field-induced weak ferromagnetism in the FeOOH layer and its coupling with the underlying alpha-Fe.