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Magneto-ionics has emerged as a promising approach to manipulate magnetic properties, not only by drastically reducing power consumption associated with electric current based devices but also by enabling novel functionalities. To date, magneto-ionics have been mostly explored in oxygen-based systems, while there is a surge of interest in alternative ionic systems. Here we demonstrate highly effective hydroxide-based magneto-ionics in electrodeposited α-Co(OH) 2 films. The α-Co(OH) 2 , which is a room temperature paramagnet, is switched to ferromagnetic after electrolyte gating with a negative voltage. The system is fully, magnetically reversible upon positive voltage application. The origin of the reversible paramagnetic-to-ferromagnetic transition is attributed to the ionic diffusion of hydroxyl groups, promoting the formation of metallic cobalt ferromagnetic regions. Our findings demonstrate one of the lowest turn-on voltages reported for propylene carbonate gated experiments. By tuning the voltage magnitude and sample area we demonstrate that the speed of the induced ionic effect can be drastically enhanced.
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Room‐Temperature Solid‐State Nitrogen‐Based Magneto‐Ionics in Co x Mn 1−x N Films
Abstract The increasing energy demand in information technologies requires novel low‐power procedures to store and process data. Magnetic materials, central to these technologies, are usually controlled through magnetic fields or spin‐polarized currents that are prone to the Joule heating effect. Magneto‐ionics is a unique energy‐efficient strategy to control magnetism that can induce large non‐volatile modulation of magnetization, coercivity and other properties through voltage‐driven ionic motion. Recent studies have shown promising magneto‐ionic effects using nitrogen ions. However, either liquid electrolytes or prior annealing procedures are necessary to induce the desired N‐ion motion. In this work, magneto‐ionic effects are voltage‐triggered at room temperature in solid state systems of CoxMn1‐xN films, without the need of thermal annealing. Upon gating, a rearrangement of nitrogen ions in the layers is observed, leading to changes in the co‐existing ferromagnetic and antiferromagnetic phases, which result in substantial increase of magnetization at room temperature and modulation of the exchange bias effect at low temperatures. A detailed correlation between the structural and magnetic evolution of the system upon voltage actuation is provided. The obtained results offer promising new avenues for the utilization of nitride compounds in energy‐efficient spintronic and other memory devices.
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- PAR ID:
- 10576794
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Functional Materials
- Volume:
- 34
- Issue:
- 42
- ISSN:
- 1616-301X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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