Magneto-Ionic Switching of Superparamagnetism

Markus Gößler; Heinz Krenn; Roland Würschum

Abstract

Nanoporous materials are promising candidates for the voltage-control of magnetism in electrochemical setups due to their large surface-to-volume ratios. Here, we introduce the class of dealloyed nanoporous metals in the field of magneto-ionics. Electrochemical dealloying is a selective corrosion process from an alloy, which allows preparing a great variety of metallic nanoporous structures. While the lesser noble element is gradually removed, the nobler component rearranges during the corrosion process forming nanometre-size ligaments. Inevitably a small fraction of the sacrificial element is buried in ‘clusters’ under the noble metal surface during dealloying [1], which we utilised for the magnetic functionalisation of our structures. A ferromagnetic sacrificial element in the dealloying process, gives the option to prepare nanoporous structures with embedded magnetic nanoparticles in a one-step process.
In this work nanoporous palladium containing clusters of cobalt -npPd(Co)- is prepared from a CoPd alloy. High-resolution TEM in combination with elemental mapping techniques revealed a residual cobalt concentration of about 8 at% agglomerated in clusters with an average size of 1.5-2 nm. Palladium is not only a high-susceptibility paramagnet attractive for magnetic tuning, but also known for its ability to store large amounts of hydrogen in the crystal lattice. Our magneto-ionic approach attempts to bias magnetic properties of Co-clusters in the Pd-matrix via electrochemical hydrogenation.
Hydrogenation was conducted in an in situ electrochemical cell in a SQUID-magnetometer, allowing a direct determination of the changes in magnetisation. Upon voltammetric cycling in the electrochemical hydrogen regime magnetisation was reversibly altered by more than 600%, corresponding to a complete On- and Off-switching of magnetism. A novel magneto-ionic mechanism, based on a RKKY-mediated cluster coupling upon hydrogenation, is proposed to account for the unexpectedly large changes upon hydrogenation [2].
This work is financially supported by the Austrian Science Fund (FWF): P30070-N36.
References
[1] T.Krekeler, A. V. Straßer, M. Graf, K. Wang, C.Hartig, M. Ritter, J. Weissmüller, Mater. Res. Lett. 5, 314, (2017)
[2] M.Gößler, M. Albu, G. Klinser, E.-M. Steyskal, H. Krenn, R. Würschum,
Small 15, 1904523, (2019)

Original language	English
Publication status	Published - 28 Jan 2020
Event	Energy Efficient Magnetoelectric Materials by Ionic Approaches: Fundamentals, Challenges and Perspectives: 712. WE-Heraeus-Seminar - Physikzentrum, Bad Honnef, Germany Duration: 26 Jan 2020 → 29 Jan 2020 https://www.we-heraeus-stiftung.de/veranstaltungen/seminare/2020/energy-efficient-magnetoelectric-materials-by-ionic-approaches-fundamentals-challenges-and-perspectives/venue/

Seminar

Seminar	Energy Efficient Magnetoelectric Materials by Ionic Approaches: Fundamentals, Challenges and Perspectives
Country/Territory	Germany
City	Bad Honnef
Period	26/01/20 → 29/01/20
Internet address	https://www.we-heraeus-stiftung.de/veranstaltungen/seminare/2020/energy-efficient-magnetoelectric-materials-by-ionic-approaches-fundamentals-challenges-and-perspectives/venue/

Fields of Expertise

Advanced Materials Science

1 Finished
1 Active

Energy Materials & Nanomaterials
Brossmann, U., Steyskal, E., Würschum, R. & Klinser, G.
1/01/00 → …
Project: Research area
FWF - Nanoporös - In-situ magnetometry of nanoporous metals during dealloying and charging
Würschum, R., Steyskal, E. & Gößler, M.
17/07/17 → 16/10/21
Project: Research project

Magneto-Ionic Switching of Superparamagnetism
Markus Gößler (Speaker), Heinz Krenn (Contributor) & Roland Würschum (Contributor)
28 Jan 2020
Activity: Talk or presentation › Talk at conference or symposium › Science to science

Cite this

@conference{75f26f425fae4217a7b332babd382844,

title = "Magneto-Ionic Switching of Superparamagnetism",

abstract = "Nanoporous materials are promising candidates for the voltage-control of magnetism in electrochemical setups due to their large surface-to-volume ratios. Here, we introduce the class of dealloyed nanoporous metals in the field of magneto-ionics. Electrochemical dealloying is a selective corrosion process from an alloy, which allows preparing a great variety of metallic nanoporous structures. While the lesser noble element is gradually removed, the nobler component rearranges during the corrosion process forming nanometre-size ligaments. Inevitably a small fraction of the sacrificial element is buried in {\textquoteleft}clusters{\textquoteright} under the noble metal surface during dealloying [1], which we utilised for the magnetic functionalisation of our structures. A ferromagnetic sacrificial element in the dealloying process, gives the option to prepare nanoporous structures with embedded magnetic nanoparticles in a one-step process. In this work nanoporous palladium containing clusters of cobalt -npPd(Co)- is prepared from a CoPd alloy. High-resolution TEM in combination with elemental mapping techniques revealed a residual cobalt concentration of about 8 at% agglomerated in clusters with an average size of 1.5-2 nm. Palladium is not only a high-susceptibility paramagnet attractive for magnetic tuning, but also known for its ability to store large amounts of hydrogen in the crystal lattice. Our magneto-ionic approach attempts to bias magnetic properties of Co-clusters in the Pd-matrix via electrochemical hydrogenation. Hydrogenation was conducted in an in situ electrochemical cell in a SQUID-magnetometer, allowing a direct determination of the changes in magnetisation. Upon voltammetric cycling in the electrochemical hydrogen regime magnetisation was reversibly altered by more than 600%, corresponding to a complete On- and Off-switching of magnetism. A novel magneto-ionic mechanism, based on a RKKY-mediated cluster coupling upon hydrogenation, is proposed to account for the unexpectedly large changes upon hydrogenation [2]. This work is financially supported by the Austrian Science Fund (FWF): P30070-N36. References[1] T.Krekeler, A. V. Stra{\ss}er, M. Graf, K. Wang, C.Hartig, M. Ritter, J. Weissm{\"u}ller, Mater. Res. Lett. 5, 314, (2017)[2] M.G{\"o}{\ss}ler, M. Albu, G. Klinser, E.-M. Steyskal, H. Krenn, R. W{\"u}rschum, Small 15, 1904523, (2019)",

author = "Markus G{\"o}{\ss}ler and Heinz Krenn and Roland W{\"u}rschum",

year = "2020",

month = jan,

day = "28",

language = "English",

note = "Energy Efficient Magnetoelectric Materials by Ionic Approaches: Fundamentals, Challenges and Perspectives : 712. WE-Heraeus-Seminar ; Conference date: 26-01-2020 Through 29-01-2020",

url = "https://www.we-heraeus-stiftung.de/veranstaltungen/seminare/2020/energy-efficient-magnetoelectric-materials-by-ionic-approaches-fundamentals-challenges-and-perspectives/venue/",

}

TY - CONF

T1 - Magneto-Ionic Switching of Superparamagnetism

AU - Gößler, Markus

AU - Krenn, Heinz

AU - Würschum, Roland

PY - 2020/1/28

Y1 - 2020/1/28

N2 - Nanoporous materials are promising candidates for the voltage-control of magnetism in electrochemical setups due to their large surface-to-volume ratios. Here, we introduce the class of dealloyed nanoporous metals in the field of magneto-ionics. Electrochemical dealloying is a selective corrosion process from an alloy, which allows preparing a great variety of metallic nanoporous structures. While the lesser noble element is gradually removed, the nobler component rearranges during the corrosion process forming nanometre-size ligaments. Inevitably a small fraction of the sacrificial element is buried in ‘clusters’ under the noble metal surface during dealloying [1], which we utilised for the magnetic functionalisation of our structures. A ferromagnetic sacrificial element in the dealloying process, gives the option to prepare nanoporous structures with embedded magnetic nanoparticles in a one-step process. In this work nanoporous palladium containing clusters of cobalt -npPd(Co)- is prepared from a CoPd alloy. High-resolution TEM in combination with elemental mapping techniques revealed a residual cobalt concentration of about 8 at% agglomerated in clusters with an average size of 1.5-2 nm. Palladium is not only a high-susceptibility paramagnet attractive for magnetic tuning, but also known for its ability to store large amounts of hydrogen in the crystal lattice. Our magneto-ionic approach attempts to bias magnetic properties of Co-clusters in the Pd-matrix via electrochemical hydrogenation. Hydrogenation was conducted in an in situ electrochemical cell in a SQUID-magnetometer, allowing a direct determination of the changes in magnetisation. Upon voltammetric cycling in the electrochemical hydrogen regime magnetisation was reversibly altered by more than 600%, corresponding to a complete On- and Off-switching of magnetism. A novel magneto-ionic mechanism, based on a RKKY-mediated cluster coupling upon hydrogenation, is proposed to account for the unexpectedly large changes upon hydrogenation [2]. This work is financially supported by the Austrian Science Fund (FWF): P30070-N36. References[1] T.Krekeler, A. V. Straßer, M. Graf, K. Wang, C.Hartig, M. Ritter, J. Weissmüller, Mater. Res. Lett. 5, 314, (2017)[2] M.Gößler, M. Albu, G. Klinser, E.-M. Steyskal, H. Krenn, R. Würschum, Small 15, 1904523, (2019)

AB - Nanoporous materials are promising candidates for the voltage-control of magnetism in electrochemical setups due to their large surface-to-volume ratios. Here, we introduce the class of dealloyed nanoporous metals in the field of magneto-ionics. Electrochemical dealloying is a selective corrosion process from an alloy, which allows preparing a great variety of metallic nanoporous structures. While the lesser noble element is gradually removed, the nobler component rearranges during the corrosion process forming nanometre-size ligaments. Inevitably a small fraction of the sacrificial element is buried in ‘clusters’ under the noble metal surface during dealloying [1], which we utilised for the magnetic functionalisation of our structures. A ferromagnetic sacrificial element in the dealloying process, gives the option to prepare nanoporous structures with embedded magnetic nanoparticles in a one-step process. In this work nanoporous palladium containing clusters of cobalt -npPd(Co)- is prepared from a CoPd alloy. High-resolution TEM in combination with elemental mapping techniques revealed a residual cobalt concentration of about 8 at% agglomerated in clusters with an average size of 1.5-2 nm. Palladium is not only a high-susceptibility paramagnet attractive for magnetic tuning, but also known for its ability to store large amounts of hydrogen in the crystal lattice. Our magneto-ionic approach attempts to bias magnetic properties of Co-clusters in the Pd-matrix via electrochemical hydrogenation. Hydrogenation was conducted in an in situ electrochemical cell in a SQUID-magnetometer, allowing a direct determination of the changes in magnetisation. Upon voltammetric cycling in the electrochemical hydrogen regime magnetisation was reversibly altered by more than 600%, corresponding to a complete On- and Off-switching of magnetism. A novel magneto-ionic mechanism, based on a RKKY-mediated cluster coupling upon hydrogenation, is proposed to account for the unexpectedly large changes upon hydrogenation [2]. This work is financially supported by the Austrian Science Fund (FWF): P30070-N36. References[1] T.Krekeler, A. V. Straßer, M. Graf, K. Wang, C.Hartig, M. Ritter, J. Weissmüller, Mater. Res. Lett. 5, 314, (2017)[2] M.Gößler, M. Albu, G. Klinser, E.-M. Steyskal, H. Krenn, R. Würschum, Small 15, 1904523, (2019)

M3 - Abstract

T2 - Energy Efficient Magnetoelectric Materials by Ionic Approaches: Fundamentals, Challenges and Perspectives

Y2 - 26 January 2020 through 29 January 2020

ER -

Magneto-Ionic Switching of Superparamagnetism

Abstract

Seminar

Fields of Expertise

Fingerprint

Projects

Energy Materials & Nanomaterials

FWF - Nanoporös - In-situ magnetometry of nanoporous metals during dealloying and charging

Activities

Magneto-Ionic Switching of Superparamagnetism

Cite this