Structural and Magnetic Depth Profiles of Magneto-Ionic Heterostructures Beyond the Interface Limit

Published

July 22, 2016

Author(s)

Dustin A. Gilbert, Alexander J. Grutter, Elke Arenholz, Kai Liu, Brian J. Kirby, Julie A. Borchers, Brian B. Maranville

Abstract

Electric-field control of magnetism provides a promising route towards ultralow power information storage and sensor technologies. The effects of magneto-ionic motion have so far been prominently featured in the direct modification of interface chemical and physical characteristic. Here we demonstrate magnetoelectric coupling moderated by voltage-driven oxygen migration beyond the interface limit in relatively thick AlO_x/GdI_x/Co (15 nm) films. Oxygen migration and its ramifications on the Co magnetization are quantitatively mapped with polarized neutron reflectometry under thermal and electro-thermal conditionings. The depth-resolved profiles uniquely identify interfacial and bulk behaviors and a semi-reversible suppression and recovery of the magnetization. Magnetometry measurements show that the conditioning changes the microstructure so a to disrupt long-range ferromagnetic ordering, resulting in an additional magnetically soft phase. X-ray spectroscopy confirms electric field induced changes in the Co oxidation state but not in the Gd, suggesting that the GdO_x transmits oxygen but does not source or sink it. These results together provide crucial insight into controlling magnetic heterostructures via magneto-ionic motion, not only at the interface, but also throughout the bulk of the films.

Citation

Nature Communications

Volume

7

Issue

12264

Pub Type

Journals

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Keywords

Magnetism, magneto-ionic, oxidation, electric field, neutron scattering, FORC, XAS, XMCD

Citation

Gilbert, D. , Grutter, A. , Arenholz, E. , Liu, K. , Kirby, B. , Borchers, J. and , B. (2016), Structural and Magnetic Depth Profiles of Magneto-Ionic Heterostructures Beyond the Interface Limit, Nature Communications, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=920719 (Accessed April 26, 2024)