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Title: Reversible Control of Interfacial Magnetism through Ionic-Liquid-Assisted Polarization Switching

Abstract

The ability to control magnetism of materials via electric field enables a myriad of technological innovations in information storage, sensing, and computing. In this paper, we use ionic-liquid-assisted ferroelectric switching to demonstrate reversible modulation of interfacial magnetism in a multiferroic heterostructure composed of ferromagnetic (FM) La 0.8Sr 0.2MnO 3 and ferroelectric (FE) PbZr 0.2Ti 0.8O 3. It is shown that ionic liquids can be used to persistently and reversibly switch a large area of a FE film. Finally, this is a prerequisite for polarized neutron reflectometry (PNR) studies that are conducted to directly probe magnetoelectric coupling of the FE polarization to the interfacial magnetization.

Authors:
ORCiD logo; ; ; ; ORCiD logo; ; ;
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); USDOE Laboratory Directed Research and Development (LDRD) Program
OSTI Identifier:
1343529
Grant/Contract Number:
AC05-00OR22725
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Nano Letters
Additional Journal Information:
Journal Volume: 17; Journal Issue: 3; Journal ID: ISSN 1530-6984
Publisher:
American Chemical Society
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ferroelectric field effect; ionic liquid gating; Magnetoelectric coupling; polarized neutron reflectometry; strongly correlated oxide

Citation Formats

Herklotz, Andreas, Guo, Er-Jia, Wong, Anthony T., Meyer, Tricia L., Dai, Sheng, Ward, T. Zac, Lee, Ho Nyung, and Fitzsimmons, Michael R.. Reversible Control of Interfacial Magnetism through Ionic-Liquid-Assisted Polarization Switching. United States: N. p., 2017. Web. doi:10.1021/acs.nanolett.6b04949.
Herklotz, Andreas, Guo, Er-Jia, Wong, Anthony T., Meyer, Tricia L., Dai, Sheng, Ward, T. Zac, Lee, Ho Nyung, & Fitzsimmons, Michael R.. Reversible Control of Interfacial Magnetism through Ionic-Liquid-Assisted Polarization Switching. United States. doi:10.1021/acs.nanolett.6b04949.
Herklotz, Andreas, Guo, Er-Jia, Wong, Anthony T., Meyer, Tricia L., Dai, Sheng, Ward, T. Zac, Lee, Ho Nyung, and Fitzsimmons, Michael R.. Mon . "Reversible Control of Interfacial Magnetism through Ionic-Liquid-Assisted Polarization Switching". United States. doi:10.1021/acs.nanolett.6b04949. https://www.osti.gov/servlets/purl/1343529.
@article{osti_1343529,
title = {Reversible Control of Interfacial Magnetism through Ionic-Liquid-Assisted Polarization Switching},
author = {Herklotz, Andreas and Guo, Er-Jia and Wong, Anthony T. and Meyer, Tricia L. and Dai, Sheng and Ward, T. Zac and Lee, Ho Nyung and Fitzsimmons, Michael R.},
abstractNote = {The ability to control magnetism of materials via electric field enables a myriad of technological innovations in information storage, sensing, and computing. In this paper, we use ionic-liquid-assisted ferroelectric switching to demonstrate reversible modulation of interfacial magnetism in a multiferroic heterostructure composed of ferromagnetic (FM) La0.8Sr0.2MnO3 and ferroelectric (FE) PbZr0.2Ti0.8O3. It is shown that ionic liquids can be used to persistently and reversibly switch a large area of a FE film. Finally, this is a prerequisite for polarized neutron reflectometry (PNR) studies that are conducted to directly probe magnetoelectric coupling of the FE polarization to the interfacial magnetization.},
doi = {10.1021/acs.nanolett.6b04949},
journal = {Nano Letters},
number = 3,
volume = 17,
place = {United States},
year = {Mon Feb 06 00:00:00 EST 2017},
month = {Mon Feb 06 00:00:00 EST 2017}
}

Journal Article:
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Citation Metrics:
Cited by: 5works
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  • Ionic-liquid gating on a functional thin film with a low voltage has drawn a lot of attention due to rich chemical, electronic, and magnetic phenomena at the interface. A key challenge in quantitative determination of voltage-controlled magnetic anisotropy (VCMA) in Au/[DEME] +[TFSI] -/Co field-effect transistor heterostructures is addressed. The magnetic anisotropy change as response to the gating voltage is precisely detected by in situ electron spin resonance measurements. Furthermore, a reversible change of magnetic anisotropy up to 219 Oe is achieved with a low gating voltage of 1.5 V at room temperature, corresponding to a record high VCMA coefficient ofmore » ≈146 Oe V -1. Two gating effects, the electrostatic doping and electrochemical reaction, are distinguished at various gating voltage regions, as confirmed by X-ray photoelectron spectroscopy and atomic force microscopy experiments. Our work shows a unique ionic-liquid-gating system for strong interfacial magnetoelectric coupling with many practical advantages, paving the way toward ion-liquid-gating spintronic/electronic devices.« less
  • E-field control of interfacial exchange coupling and deterministic switching of magnetization have been demonstrated in two sets of ferromagnetic(FM)/antiferromagnetic(AFM)/ferroelectric(FE) multiferroic heterostructures, including NiFe/NiCoO/glass/PZN-PT (011) and NiFe/FeMn/glass/PZN-PT (011). We designed this experiment to achieve exchange bias tuning along the magnetic easy axis, which is critical for realizing reversible 180° magnetization deterministic switching at zero or small magnetic bias. Strong exchange coupling were established across AFM-FM interfaces, which plays an important role in voltage control of magnetization switching. Through the competition between the E-field induced uniaxial anisotropy in ferromagnetic layer and unidirectional anisotropy in antiferromagnetic layer, the exchange bias was significantly shiftedmore » by up to |ΔH ex|/H ex=8% in NiFe/FeMn/glass/PZN-PT (011) and 13% in NiFe/NiCoO/glass/PZN-PT (011). In addition, the square shape of the hysteresis loop, as well as a strong shape tunability of |ΔH ex|/H c=67.5~125% in NiFe/FeMn/glass/PZN-PT and 30~38% in NiFe/NiCoO/glass/PZN-PT were achieved, which lead to a near 180° magnetization switching. Lastly, electrical tuning of interfacial exchange coupling in FM/AFM/FE systems paves a new way for realizing magnetoelectric random access memories and other memory technologies.« less
  • We demonstrate reversible control of magnetization and anisotropy in La 0.67Sr 0.33MnO 3 films through interfacial oxygen migration. Gd metal capping layers deposited onto La 0.67Sr 0.33MnO 3 leach oxygen from the film through a solid-state redox reaction to form porous Gd 2O 3. X-ray absorption and polarized neutron reflectometry measurements show Mn valence alterations consistent with high oxygen vacancy concentrations, resulting in suppressed magnetization and increased coercive fields. Effects of the oxygen migration are observed both at the interface and also throughout the majority of a 40 nm thick film, suggesting extensive diffusion of oxygen vacancies. After Gd-capped Lamore » 0.67Sr 0.33MnO 3 is exposed to atmospheric oxygen for a prolonged period of time, oxygen diffuses through the Gd 2O 3 layer and the magnetization of the La 0.67Sr 0.33MnO 3 returns to the uncapped value. In conclusion, these findings showcase perovskite heterostructures as ideal candidates for developing functional interfaces through chemically-induced oxygen migration.« less
  • We demonstrate that magnetic properties of ultra-thin Co films adjacent to Gd2O3 gate oxides can be directly manipulated by external electric fields. The Co films can be reversibly changed from an optimally-oxidized state with a strong perpendicular magnetic anisotropy to a metallic state with an in-plane magnetic anisotropy, or to a fully-oxidized state with nearly zero magnetization, depending on the polarity and time duration of the applied electric fields. Consequently, an unprecedentedly large change of magnetic anisotropy energy up to 0.73 erg/cm2 has been realized in a nonvolatile manner using gate voltages of only a few volts. These results openmore » a new route to achieve ultralow energy magnetization manipulation in spintronic devices.« less