Enhancing magneto-ionic effects in cobalt oxide films by electrolyte engineering

Martins, Sofia; Ma, Zheng; Solans‐Monfort, Xavier; Sodupe, Mariona; Rodrı́guez-Santiago, Luis; Menéndez, Enric; Pellicer, Eva; Sort, Jordi

doi:10.1039/d2nh00340f

Cited by 4 publications

(3 citation statements)

References 34 publications

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“…A control experiment was carried out to verify this using metallic cobalt powder in a I 2 -containing PC electrolyte (see Section 4, Supplementary Information ). No iodine signal is observed either in the solid material, so no additional phases containing iodine form, in agreement with previous works using this electrolyte 28 . Open circuit potentials and initial voltammetry potentials are very stable and constant, evidencing no spontaneous direct reactions in the setting.…”

Section: Resultssupporting

confidence: 92%

“…This difference is partially because, during the BPE experiment, the voltage induced at the film is much smaller than the externally applied driving voltage (e.g., the film is under 1 V when the Pt electrodes are biased at 15 V in the vertical BPE devices, as discussed in Section 5 of the Supplementary Information ). Other contributing factors are the larger potentials used in the reported direct-wiring case, where the gating voltage was 50 V, and the use of different electrolyte media 28 .…”

Section: Resultsmentioning

confidence: 99%

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Wireless magneto-ionics: voltage control of magnetism by bipolar electrochemistry

Ma,

Fuentes-Rodriguez,

Tan

et al. 2023

Nat Commun

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Modulation of magnetic properties through voltage-driven ion motion and redox processes, i.e., magneto-ionics, is a unique approach to control magnetism with electric field for low-power memory and spintronic applications. So far, magneto-ionics has been achieved through direct electrical connections to the actuated material. Here we evidence that an alternative way to reach such control exists in a wireless manner. Induced polarization in the conducting material immersed in the electrolyte, without direct wire contact, promotes wireless bipolar electrochemistry, an alternative pathway to achieve voltage-driven control of magnetism based on the same electrochemical processes involved in direct-contact magneto-ionics. A significant tunability of magnetization is accomplished for cobalt nitride thin films, including transitions between paramagnetic and ferromagnetic states. Such effects can be either volatile or non-volatile depending on the electrochemical cell configuration. These results represent a fundamental breakthrough that may inspire future device designs for applications in bioelectronics, catalysis, neuromorphic computing, or wireless communications.

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Section: Resultssupporting

confidence: 92%

Section: Resultsmentioning

confidence: 99%

Wireless magneto-ionics: voltage control of magnetism by bipolar electrochemistry

Ma,

Fuentes-Rodriguez,

Tan

et al. 2023

Nat Commun

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“…An extreme case is when voltage induces a complete reversible transition between FM and nonmagnetic states, leading to voltage-driven ON–OFF switching of ferromagnetism. This has been reported in a number of magneto-ionic systems, such as Co 3 O 4 , ,, Li + -intercalated α-Fe 2 O 3 , F – -intercalated La 2–2 x Sr 1+2 x Mn 2 O 7 , CoN, , CoMnN, or α-Co(OH) 2 . ON–OFF switching of the ferromagnetic state has been also induced by electrostatic surface charging in FeS 2 …”

mentioning

confidence: 65%

Regulating Oxygen Ion Transport at the Nanoscale to Enable Highly Cyclable Magneto-Ionic Control of Magnetism

Tan

Fuentes-Rodríguez

et al. 2023

ACS Nano

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Magneto-ionics refers to the control of magnetic properties of materials through voltage-driven ion motion. To generate effective electric fields, either solid or liquid electrolytes are utilized, which also serve as ion reservoirs. Thin solid electrolytes have difficulties in (i) withstanding high electric fields without electric pinholes and (ii) maintaining stable ion transport during long-term actuation. In turn, the use of liquid electrolytes can result in poor cyclability, thus limiting their applicability. Here we propose a nanoscale-engineered magneto-ionic architecture (comprising a thin solid electrolyte in contact with a liquid electrolyte) that drastically enhances cyclability while preserving sufficiently high electric fields to trigger ion motion. Specifically, we show that the insertion of a highly nanostructured (amorphous-like) Ta layer (with suitable thickness and electric resistivity) between a magneto-ionic target material (i.e., Co3O4) and the liquid electrolyte increases magneto-ionic cyclability from <30 cycles (when no Ta is inserted) to more than 800 cycles. Transmission electron microscopy together with variable energy positron annihilation spectroscopy reveals the crucial role of the generated TaO x interlayer as a solid electrolyte (i.e., ionic conductor) that improves magneto-ionic endurance by proper tuning of the types of voltage-driven structural defects. The Ta layer is very effective in trapping oxygen and hindering O2– ions from moving into the liquid electrolyte, thus keeping O2– motion mainly restricted between Co3O4 and Ta when voltage of alternating polarity is applied. We demonstrate that this approach provides a suitable strategy to boost magneto-ionics by combining the benefits of solid and liquid electrolytes in a synergetic manner.

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Magnetoionics for Synaptic Devices and Neuromorphic Computing: Recent Advances, Challenges, and Future Perspectives

Monalisha,

Ameziane,

Spasojevic

et al. 2024

Small Science

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With the advent of Big Data, traditional digital computing is struggling to cope with intricate tasks related to data classification or pattern recognition. To mitigate this limitation, software‐based neural networks are implemented, but they are run in conventional computers whose operation principle (with separate memory and data‐processing units) is highly inefficient compared to the human brain. Brain‐inspired in‐memory computing is achieved through a wide variety of methods, for example, artificial synapses, spiking neural networks, or reservoir computing. However, most of these methods use materials (e.g., memristor arrays, spintronics, phase change memories) operated with electric currents, resulting in significant Joule heating effect. Tuning magnetic properties by voltage‐driven ion motion (i.e., magnetoionics) has recently emerged as an alternative energy‐efficient approach to emulate functionalities of biological synapses: potentiation/depression, multilevel storage, or transitions from short‐term to long‐term plasticity. In this perspective, the use of magnetoionics in neuromorphic applications is critically reviewed, with emphasis on modulating synaptic weight through: 1) control of magnetization by voltage‐induced ion retrieval/insertion; and 2) control of magnetic stripe domains and skyrmions in gated magnetic thin films adjacent to solid‐state ionic supercapacitors. The potential prospects in this emerging research area together with a forward‐looking discussion on future opportunities are provided.

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Enhancing magneto-ionic effects in cobalt oxide films by electrolyte engineering

Abstract: Electric-field-driven ion motion to tailor magnetic properties of materials (magneto-ionics) offers much promise in the pursuit of voltage-controlled magnetism for highly energy-efficient spintronic devices. Electrolyte gating is a relevant means...

Cited by 4 publications

References 34 publications

Wireless magneto-ionics: voltage control of magnetism by bipolar electrochemistry

Wireless magneto-ionics: voltage control of magnetism by bipolar electrochemistry

Regulating Oxygen Ion Transport at the Nanoscale to Enable Highly Cyclable Magneto-Ionic Control of Magnetism

Magnetoionics for Synaptic Devices and Neuromorphic Computing: Recent Advances, Challenges, and Future Perspectives

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