Voltage-controlled ON switching and manipulation of magnetization via the redox transformation of β-FeOOH nanoplatelets

Nichterwitz, Martin; Neitsch, Sabine; Röher, Stefan; Wolf, Daniel; Nielsch, Kornelius; Leistner, K.

doi:10.1088/1361-6463/ab5bca

Cited by 10 publications

(7 citation statements)

References 42 publications

(77 reference statements)

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“…Additionally, under inert atmosphere, Fe(OH) 2 could be not stable in presence of hydroxyl ions. Indeed, we can expect the following reaction [ 23 ]: Fe(OH) 2 + OH − → FeOOH + H 2 O + e − which leads to the formation of a polymorph of oxy-hydroxides compounds [ 24 ].…”

Section: Methodsmentioning

confidence: 99%

New Sustainable, Scalable and One-Step Synthesis of Iron Oxide Nanoparticles by Ion Exchange Process

et al. 2021

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This work introduces an innovative, sustainable, and scalable synthesis of iron oxides nanoparticles (NPs) in aqueous suspension. The method, based on ion exchange process, consists of a one-step procedure, time and energy saving, operating in water and at room temperature, by cheap and renewable reagents. The influence of both oxidation state of the initial reagent and reaction atmosphere is considered. Three kinds of iron nanostructured compounds are obtained (2-lines ferrihydrite; layered-structure iron oxyhydroxide δ-FeOOH; and cubic magnetite), in turn used as precursors to obtain hematite and maghemite NPs. All the produced NPs are characterized by a high purity, small particles dimensions (from 2 to 50 nm), and high specific surface area values up to 420 m2/g, with yields of production >90%. In particular, among the most common iron oxide NPs, we obtained cubic magnetite NPs at room temperature, characterized by particle dimensions of about 6 nm and a surface area of 170 m2/g. We also obtained hematite NPs at very low temperature conditions (that is 2 h at 200 °C), characterized by particles dimensions of about 5 nm with a surface area value of 200 m2/g. The obtained results underline the strength of the synthetic method to provide a new, sustainable, tunable, and scalable high-quality production.

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Section: Methodsmentioning

confidence: 99%

New Sustainable, Scalable and One-Step Synthesis of Iron Oxide Nanoparticles by Ion Exchange Process

et al. 2021

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“…The retained magnetoionic effect after the break indicates that the reduction to iron and the resulting magneto-ionic effect are robust and do not largely depend on the exact nature of the starting iron oxide or hydroxide, which is in line with previous electrochemical and magneto-ionic studies. 50,66,67 Even though scattering of the MR values for the "ON" and "OFF" states set by reduction and oxidation voltages is still high (Figure 3f), a clear distinction between these states is possible.…”

Section: Functionalization Of Aerogel Network With Iron Hydroxide/iro...mentioning

confidence: 99%

Voltage-Controlled ON–OFF-Switching of Magnetoresistance in FeO_x/Fe/Au Aerogel Networks

Nichterwitz,

Hiekel,

Wolf

et al. 2023

ACS Mater. Au

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Voltage control of magnetoresistance (MR) in nanoscale three-dimensional (3D) geometries is interesting from a fundamental point of view and a promising route toward novel sensors and energy-efficient computing schemes. Magneto-ionic mechanisms are favorable for low-voltage control of magnetism and room-temperature operation, but magneto-ionic control of MR has been studied only for planar geometries so far. We synthesize a 3D nanomaterial with magneto-ionic functionality by electrodepositing an iron hydroxide/iron coating on a porous nanoscale gold network (aerogel). To enable maximum magneto-ionic ON−OFF-switching, the thickness of the coating is adjusted to a few nanometers by a selfterminating electrodeposition process. In situ magnetotransport measurements during electrolytic gating of these nanostructures reveal large reversible changes in MR, including ON−OFF-switching of MR, with a small applied voltage difference (1.72 V). This effect is related to the electrochemical switching between a ferromagnetic iron shell/gold core nanostructure (negative MR at the reduction voltage) and an iron oxide shell/gold core nanostructure (negligible MR at the oxidation voltage).

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“…[ 30 ] Yet, α‐Fe 2 O 3 particles larger than 1 µm undergo irreversible changes in magnetism and cannot sustain large lithium intercalation. [ 30,36 ] Remarkably, almost complete ON/OFF switching was recently reported for β‐FeOOH nanoplatelets in an alkaline Li‐based electrolyte at room temperature [ 37 ] and electrodeposited Fe naturally covered by a thin layer of FeO x tested in aqueous KOH solution. [ 38 ] However, in the former case, the platelet nanostructure collapsed after first voltage cycle and could not be recovered.…”

Section: Introductionmentioning

confidence: 95%

Voltage‐Induced ON Switching of Magnetism in Ordered Arrays of Non‐Ferrimagnetic Nanoporous Iron Oxide Microdisks

Cialone

Nicolenco

Robbennolt

et al. 2020

Adv Materials Inter

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Tailoring the magnetic properties of ordered arrays of patterned structures usually requires stringent control of their size, pitch, microstructure, and composition. Here, a fundamentally different approach to manipulate the magnetic behavior of lithographed microdisks, based on the application of electrical voltage, is demonstrated. First, highly porous iron oxide films with virtually no magnetic response (OFF state) are grown by sol–gel chemistry. Subsequently, arrays of microdisks (8 µm in diameter) are obtained combining lithography with wet chemical etching processes. Electrolyte‐gating (with an anhydrous electrolyte) is then employed to induce a tunable (i.e., “on‐demand”) ferromagnetic response in these disks (OFF–ON switching of magnetism) at room temperature. The changes in magnetic properties are attributed to magnetoelectrically‐driven oxygen ion migration, which is enhanced due to nanoporosity. This causes partial reduction of the oxide phases to metallic Fe. The effect can be considerably reversed by applying voltage of opposite polarity. These results are appealing for diverse technological applications that require the use of patterned structures with easily tunable magnetic properties, such as magnetic micro‐electro‐mechanical systems, microfluidic, and lab‐on‐a‐chip platforms for biomedical therapies and, ultimately, energy‐efficient magnetic memories or neuromorphic computing.

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Voltage-controlled ON switching and manipulation of magnetization via the redox transformation of β-FeOOH nanoplatelets

Cited by 10 publications

References 42 publications

New Sustainable, Scalable and One-Step Synthesis of Iron Oxide Nanoparticles by Ion Exchange Process

New Sustainable, Scalable and One-Step Synthesis of Iron Oxide Nanoparticles by Ion Exchange Process

Voltage-Controlled ON–OFF-Switching of Magnetoresistance in FeO_x/Fe/Au Aerogel Networks

Voltage‐Induced ON Switching of Magnetism in Ordered Arrays of Non‐Ferrimagnetic Nanoporous Iron Oxide Microdisks

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Voltage-controlled ON switching and manipulation of magnetization via the redox transformation of β-FeOOH nanoplatelets

Cited by 10 publications

References 42 publications

New Sustainable, Scalable and One-Step Synthesis of Iron Oxide Nanoparticles by Ion Exchange Process

New Sustainable, Scalable and One-Step Synthesis of Iron Oxide Nanoparticles by Ion Exchange Process

Voltage-Controlled ON–OFF-Switching of Magnetoresistance in FeOx/Fe/Au Aerogel Networks

Voltage‐Induced ON Switching of Magnetism in Ordered Arrays of Non‐Ferrimagnetic Nanoporous Iron Oxide Microdisks

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Voltage-Controlled ON–OFF-Switching of Magnetoresistance in FeO_x/Fe/Au Aerogel Networks