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Published March 10, 2024 | Version v1
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Non-Oxidative Mechanism in Oxygen-Based Magneto-Ionics

Creators

  • 1. Centre de Nanosciences et de Nanotechnologies CNRS, Université Paris-Saclay 91120 Palaiseau, France
  • 2. Synchrotron SOLEIL L'Orme des Merisiers, 91190 Saint-Aubin, France
  • 3. IMM-CNR Unit of Agrate Brianza Via C. Olivetti 2, 20864 Agrate Brianza (MB), Italy
  • 4. Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons Peter Grünberg Institute, Forschungszentrum Jülich GmbH 52425 Jülich, Germany
  • 5. Laboratoire des Sciences des Procédés et des Matériaux, CNRS-UPR 3407 Université Sorbonne Paris Nord 93430 Villetaneuse, France
  • 6. Singulus Technology AG Hanauer Landstrasse 103, 63796 Kahl am Main, Germany
  • 7. S. Ono Central Research Institute of Electric Power Industry Yokosuka, Kanagawa 240-0196, Japan
  • 8. Spin-Ion technologies, C2N 10 Boulevard Thomas Gobert, 91120 Palaiseau, France
  • 9. A. Solignac SPEC, CEA, CNRS, Université Paris-Saclay, CEA Saclay 91191 Gif-sur-Yvette Cedex, France

Description

The Ta/CoFeB/Pt/MgO/HfO2 system is investigated, whose magnetic anisotropy can be controlled through magneto-ionic gating, using both ionic liquid and solid state gating, via a non-oxidative mechanism
combining reversible and irreversible gating effects. Analysis of X-ray absorption spectroscopy at the Co and Fe edges reveals no indications of oxidation after gating, while a reversible change at the oxygen K edge suggests the involvement of oxygen species in the magneto-ionic process. In addition, X-ray diffraction measurements reveal that gating can irreversibly increase the crystalline volume of MgO, through an increase in the MgO/Mg(OH)2 ratio. This is in line with measurements in solid state devices showing that in a series of 150 gating cycles a reversible effect combines with a progressive increase in the strength of the perpendicular magnetic anisotropy contribution that saturates after extensive cycling.
Consequently, the observed gate-induced changes in magnetic anisotropy can be attributed to the combined effects of Mg(OH)2 dehydration into MgO (irreversible) and most likely a gentle reordering of oxygen species at the CoFeB interface (reversible) leading to a non-oxidative magneto-ionic mechanism. This study provides valuable insights into the underlying mechanisms governing the complex magneto-ionic phenomena, including the coexistence of both reversible and irreversible effects, and a pathway to voltage-control of crystalline order in spintronics materials.

Files

Adv Materials Inter - 2024 - Bhatnagar%E2%80%90Sch%C3%B6ffmann - Non%E2%80%90Oxidative Mechanism in Oxygen%E2%80%90Based Magneto%E2%80%90Ionics.pdf

Files (3.5 MB)

Additional details

Funding

European Commission
METASPIN 101098651

Dates

Available
2024-03-10