Lecture image placeholder

Premium content

Access to this content requires a subscription. You must be a premium user to view this content.

Monthly subscription - $9.99Pay per view - $4.99Access through your institutionLogin with Underline account
Need help?
Contact us
Lecture placeholder background
VIDEO DOI: https://doi.org/10.48448/b2x8-qv49

technical paper

MMM 2022

November 07, 2022

Minneapolis, United States

Stability of under/over oxidized magneto ionic states in Pt/Co60Fe20B20/HfO2

Magneto-ionics (MI) provides a nonvolatile EF modulation of magnetism through the migration of ions toward/away from the magnetic interfaces that allows for low-power spintronics devices. However, the ionic mechanism involved still needs to be explored, as key properties such as reversibility have been shown to strongly depend on the chemical composition and oxidation level of the ferromagnet (FM)/oxide interface, (1–3), and on the degree of crystallinity of the system (4). We have recently shown that the gate-voltage driven degree of oxidation at the FM/oxide interface in Ta/Co20Fe60B20/HfO2 defines two MI regimes: (I) underoxidized to optimally oxidized, and (II) optimally oxidized to overoxidized, accompanied by a change in the magnetization easy axis from in-plane (IP) to out-of-plane (OOP) in regime I and from OOP to IP in regime II (3). Only regime II showed reversibility, which was linked to the different binding strength of the oxygen species in regimes I and II. In this work, we present the MI behavior in Pt/Co60Fe20B20/HfO2, where also two MI regimes have been identified. In this system, both regime I and II are reversible, but the stability of the nonvolatile magnetic states was found to be significantly different in regime I and II. Magnetic states in regime I was found to be highly stable, with no significant loss of remanence in the hysteresis loops over several weeks after applying the gate voltage. In this regime, a significant variation of the Dzyaloshinskii-Moriya interaction was also observed. In contrast, the magnetic states in regime II (between OOP and IP) were found to evolve with time back to the OOP state within one day after applying the gate voltage. Interestingly, only the final overoxidized IP state is fully stable in regime II. This disparity in the stability of the MI states in regimes I and II could be attributed to differences in the gate-voltage driven chemical reactions and ionic transport, where also the composition of CoFeB may play an important role. Our results show the importance of studying the link between the ionic mechanisms and the MI state stability, in view of practical applications in spintronics.

(1) L. Herrera Diez, Y. T. Liu, M. Belmeguenai, et al., Physical Review Applied, 12, 034005 (2019);
(2) A. Fassatoui, L. Ranno, S. Pizzini, et al., Physical Review Applied, 14, 064041 (2020),
(3) R. Pachat, D. Ourdani, L. Herrera Diez. et al., Physical Review Applied, 15, 064055 (2021),
(4) R. Pachat, D. Ourdani, L. Herrera Diez, et al., Adv. Mat. Inter., Accepted (2022)


Transcript English (automatic)

Next from MMM 2022

Building spintronics neuromorphic systems with Neural Ordinary Differential Equations
technical paper

Building spintronics neuromorphic systems with Neural Ordinary Differential Equations

MMM 2022

+6Julie GrollierFlavio Abreu Araujo
Xing Chen and 8 other authors

07 November 2022

Stay up to date with the latest Underline news!

Select topic of interest (you can select more than one)


  • All Lectures
  • For Librarians
  • Resource Center
  • Free Trial
Underline Science, Inc.
1216 Broadway, 2nd Floor, New York, NY 10001, USA

© 2023 Underline - All rights reserved