Magnetic Field Magnitudes Needed for Skyrmion Generation in a General Perpendicularly Magnetized Film

Yang, Seungmo; Ju, Tae-Seong; Kim, Chang-Soo; Kim, Hyun‐Joong; An, Kay Hyeok; Moon, Kyoung‐Woong; Park, Sungkyun; Hwang, Chanyong

doi:10.1021/acs.nanolett.2c02268

Cited by 6 publications

(2 citation statements)

References 53 publications

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“…The size is inversely proportional to the applied magnetic field, as shown by the dashed black line in Figure g. This is as expected for skyrmions. − …”

Section: Resultssupporting

confidence: 75%

Effect of Surface Oxidation and Crystal Thickness on the Magnetic Properties and Magnetic Domain Structures of Cr₂Ge₂Te₆

Thomsen,

Han,

Penn

et al. 2024

ACS Nano

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van der Waals (vdW) magnetic materials, such as Cr2Ge2Te6 (CGT), show promise for memory and logic applications. This is due to their broadly tunable magnetic properties and the presence of topological magnetic features such as skyrmionic bubbles. A systematic study of thickness and oxidation effects on magnetic domain structures is important for designing devices and vdW heterostructures for practical applications. Here, we investigate thickness effects on magnetic properties, magnetic domains, and bubbles in oxidation-controlled CGT crystals. We find that CGT exposed to ambient conditions for 5 days forms an oxide layer approximately 5 nm thick. This oxidation leads to a significant increase in the oxidation state of the Cr ions, indicating a change in local magnetic properties. This is supported by real-space magnetic texture imaging through Lorentz transmission electron microscopy. By comparing the thickness-dependent saturation field of oxidized and pristine crystals, we find that oxidation leads to a nonmagnetic surface layer that is thicker than the oxide layer alone. We also find that the stripe domain width and skyrmionic bubble size are strongly affected by the crystal thickness in pristine crystals. These findings underscore the impact of thickness and surface oxidation on the properties of CGT, such as saturation field and domain/skyrmionic bubble size, and suggest a pathway for manipulating magnetic properties through a controlled oxidation process.

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“…The size is inversely proportional to the applied magnetic field, as shown by the dashed black line in Figure g. This is as expected for skyrmions. − …”

Section: Resultssupporting

confidence: 75%

Effect of Surface Oxidation and Crystal Thickness on the Magnetic Properties and Magnetic Domain Structures of Cr₂Ge₂Te₆

Thomsen,

Han,

Penn

et al. 2024

ACS Nano

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“…Due to the non-collinear spin configuration of magnetic skyrmions, the Heisenberg exchange interaction, which favors parallel alignment of neighbor spins in a ferromagnet, is unable to stabilize them. The energy of magnetic skyrmions in perpendicularly magnetized systems is determined by the competition between the perpendicular magnetic anisotropy (PMA), magnetic dipole-dipole interactions, and the Dzyaloshinskii-Moriya interaction (DMI) 5 . The PMA energy plays a crucial role in forming magnetic skyrmions in perpendicularly magnetized systems by providing a two-fold potential energy configuration.…”

mentioning

confidence: 99%

Atomic scale interface engineering for realizing a perpendicularly magnetized CoFeB-based skyrmion hosting material

Lee

Han

et al. 2023

Applied Physics Letters

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Néel-type magnetic skyrmions in perpendicularly magnetized systems have attracted considerable interest due to their potential in fundamental research on topological objects and spintronics applications. Various systems have been explored to study Néel-type magnetic skyrmions, including repeated magnetic multilayers, two-dimensional materials, and single magnetic thin-films. Among these, single magnetic thin-films, especially a CoFeB single layer, offers multiple benefits, such as reduced defect energy, high mobility, and easy integration with existing magnetoresistive random access memory technology. However, optimizing CoFeB-based skyrmion hosting materials remains challenging and requires further systematic and comprehensive investigation. In this study, we examine the effect of atomic-scale interface engineering by inserting a Ta layer between the CoFeB/MgO interface on perpendicular magnetic anisotropy, saturation magnetization, and Dzyaloshinskii–Moriya interaction. Moreover, we provide a guideline for engineering material parameters and demonstrate the validity of atomic-scale interface engineering. Our findings contribute to the development of optimized CoFeB-based skyrmion hosting materials.

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Emergent Skyrmions in Cr_0.85Te nanoflakes at Room Temperature

Ni,

Guo,

Jiang

et al. 2024

Small

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Chiral noncollinear magnetic nanostructures, such as skyrmions, are intriguing spin configurations with significant potential for magnetic memory technologies. However, the limited availability of 2D magnetic materials that host skyrmions with Curie temperatures above room temperature presents a major challenge for practical implementation. Chromium tellurides exhibit diverse spin configurations and remarkable stability under ambient conditions, making them a promising platform for fundamental spin physics research and the development of innovative 2D spintronic devices. Here, domain structures of Cr0.85Te nanoflakes synthesized via chemical vapor deposition are investigated, using magnetic force microscopy at room temperature. The results reveal that the domain width of the as‐grown nanoflakes scales with the square root of their thicknesses. Notably, the emergence and annihilation of skyrmions are observed, which can be reversibly controlled by external magnetic fields and thermal excitation in ambient air. Micromagnetic simulations suggest that the emergence of skyrmions in Cr0.85Te nanoflakes arises from inversion symmetry breaking due to compositional gradients across the sample thickness, rather than the interfacial Dzyaloshinskii–Moriya interaction. These findings provide new insights into the mechanisms underlying skyrmion formation in 2D ferromagnets and open exciting possibilities for manipulating domain structures at room temperature, offering practical pathways for developing next‐generation spintronic devices.

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Magnetic Field Magnitudes Needed for Skyrmion Generation in a General Perpendicularly Magnetized Film

Cited by 6 publications

References 53 publications

Effect of Surface Oxidation and Crystal Thickness on the Magnetic Properties and Magnetic Domain Structures of Cr₂Ge₂Te₆

Effect of Surface Oxidation and Crystal Thickness on the Magnetic Properties and Magnetic Domain Structures of Cr₂Ge₂Te₆

Atomic scale interface engineering for realizing a perpendicularly magnetized CoFeB-based skyrmion hosting material

Emergent Skyrmions in Cr_0.85Te nanoflakes at Room Temperature

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Magnetic Field Magnitudes Needed for Skyrmion Generation in a General Perpendicularly Magnetized Film

Cited by 6 publications

References 53 publications

Effect of Surface Oxidation and Crystal Thickness on the Magnetic Properties and Magnetic Domain Structures of Cr2Ge2Te6

Effect of Surface Oxidation and Crystal Thickness on the Magnetic Properties and Magnetic Domain Structures of Cr2Ge2Te6

Atomic scale interface engineering for realizing a perpendicularly magnetized CoFeB-based skyrmion hosting material

Emergent Skyrmions in Cr0.85Te nanoflakes at Room Temperature

Contact Info

Product

Resources

About

Effect of Surface Oxidation and Crystal Thickness on the Magnetic Properties and Magnetic Domain Structures of Cr₂Ge₂Te₆

Effect of Surface Oxidation and Crystal Thickness on the Magnetic Properties and Magnetic Domain Structures of Cr₂Ge₂Te₆

Emergent Skyrmions in Cr_0.85Te nanoflakes at Room Temperature