Room-Temperature Skyrmions at Zero Field in Exchange-Biased Ultrathin Films

Rana, Kumari Gaurav; Finco, Aurore; Fabre, F.; Chouaieb, S.; Haykal, Angela; Buda-Prejbeanu, L. D.; Fruchart, Olivier; Denmat, Simon Le; David, Philippe; Belmeguenai, M.; Denneulin, Thibaud; Dunin-Borkowski, Rafal E.; Gaudin, Gilles; Jacques, Vincent; Boulle, Olivier

doi:10.1103/physrevapplied.13.044079

Cited by 36 publications

(26 citation statements)

References 42 publications

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“…These responses can also be triggered using antiferromagnetic oxides (AFOs) [ 18 , 19 , 20 ], enabling new ways to tailor magnetization reversal through the EB coupling. This capability can be used to stabilize skyrmions at room temperature (RT) without external magnetic fields [ 21 , 22 , 23 ]. The EB effect induced by coupling FM with AFO might be particularly important to domain wall (DW) pinning [ 24 ], which is essential for the stabilization and optimization of the DW movement in racetrack memories [ 25 , 26 ].…”

Section: Introductionmentioning

confidence: 99%

Strong Interfacial Perpendicular Magnetic Anisotropy in Exchange-Biased NiO/Co/Au and NiO/Co/NiO Layered Systems

et al. 2021

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The ability to induce and control the perpendicular magnetic anisotropy (PMA) of ferromagnetic layers has been widely investigated, especially those that offer additional functionalities (e.g., skyrmion stabilization, voltage-based magnetization switching, rapid propagation of domain walls). Out-of-plane magnetized ferromagnetic layers in direct contact with an oxide belong to this class. Nowadays, investigation of this type of system includes antiferromagnetic oxides (AFOs) because of their potential for new approaches to applied spintronics that exploit the exchange bias (EB) coupling between the ferromagnetic and the AFO layer. Here, we investigate PMA and EB effect in NiO/Co/Au and NiO/Co/NiO layered systems. We show that the coercive and EB fields increase significantly when the Co layer is coupled with two NiO layers, instead of one. Surrounding the Co layer only with NiO layers induces a strong PMA resulting in an out-of-plane magnetized system can be obtained without a heavy metal/ferromagnetic interface. The PMA arises from a significant surface contribution (0.74 mJ/m2) that can be enhanced up to 0.99 mJ/m2 by annealing at moderate temperatures (~450 K). Using field cooling processes for both systems, we demonstrate a wide-ranging control of the exchange bias field without perturbing other magnetic properties of importance.

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Section: Introductionmentioning

confidence: 99%

Strong Interfacial Perpendicular Magnetic Anisotropy in Exchange-Biased NiO/Co/Au and NiO/Co/NiO Layered Systems

et al. 2021

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“…[ 1,2,19–25,37 ] The zero‐field skyrmion is the direct consequence of the out‐of‐plane exchange bias, which replace the role of the external magnetic field. [ 38,39 ] To create single skyrmions, the electron beam must be focused in a small area. Increasing the illumination area causes the formation of a large‐sized multidomain pattern, as shown in Figure 2b.…”

Section: Figurementioning

confidence: 99%

“…The obtained skyrmion size is comparable to those of zero‐field skyrmions in the previously studied extended multilayers that have a periodic structure. [ 26,52,53 ] Recently, zero‐field magnetic skyrmions with a mean diameter of ≈60 nm have been realized at room temperature, [ 39 ] indicating the potential to further reducing the skyrmion size in the studied materials through engineering the material parameters.…”

Section: Figurementioning

confidence: 99%

Electron Beam Lithography of Magnetic Skyrmions

et al. 2020

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The recently discovered topological magnetic skyrmion spin texture promises future innovative memory and logic devices owing to its nanoscale size and low driving current density. [1-4] Concerning their nontrivial real-space topology, skyrmions exhibit many intriguing properties, [5-8] such as the topological Hall effect, [6] the skyrmion Hall effect, [9] and the rich ferromagnetic resonance states. [10] Furthermore, long-range ordered and disordered skyrmion lattices also give rise to fascinating phenomena like a chiral magnon state [11,12] and skyrmion glass state, [13] thus providing an arena for exploring topological physics, [14,15] nonreciprocal responses, [16] and unconventional spintronic devices. [17,18] To further elucidate the physics of skyrmions and their lattices, the crucial task is to create skyrmions in a controllable manner. The emergence of magnetic skyrmions, topological spin textures, has aroused tremendous interest in studying the rich physics related to their topology. While skyrmions promise high-density and energy-efficient magnetic memory devices for information technology, the manifestation of their nontrivial topology through single skyrmions and ordered and disordered skyrmion lattices could also give rise to many fascinating physical phenomena, such as chiral magnon and skyrmion glass states. Therefore, generating skyrmions at designated locations on a large scale, while controlling the skyrmion patterns, is the key to advancing topological magnetism. Here, a new, yet general, approach to the "printing" of skyrmions with zero-field stability in arbitrary patterns on a massive scale in exchange-biased magnetic multilayers is presented. By exploiting the fact that the antiferromagnetic order can be reconfigured by local thermal excitations, a focused electron beam with a graphic pattern generator to "print" skyrmions is used, which is referred to as skyrmion lithography. This work provides a route to design arbitrary skyrmion patterns, thereby establishing the foundation for further exploration of topological magnetism.

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“…To extend the operational range beyond 10 mT, the NV centre can harness the field-dependent quench of the NV photoluminescence (PL) for magnetic imaging as demonstrated recently [11,[21][22][23]. Quench-based SNVM monitors the changes in NV PL due to the local magnetic field variation across a spin texture with the respect to the NV quantization axis.…”

Section: Introductionmentioning

confidence: 99%

“…The interpretation of quench-based SNVM maps can be ambiguous, because of the multiple parameters that influence PL quenching, such as NV-sample distance, NV axis orientation, sample magnetization, magnetic domain size or magnetic field noise [26]. Therefore, this imaging mode has been limited to the mapping of magnetic domain morphology with surface magnetisation I S 3 mA [21][22][23] (equivalent to 2 nm of Co). In this report, we reveal distinct quenchbased imaging regimes, dependent on the material parameters, and introduce the Multi-Angle Reconstruction (MARe) protocol to interpret the domain morphology from quenched SNVM maps.…”

Section: Introductionmentioning

confidence: 99%

Multi-Angle Reconstruction of Domain Morphology with All-Optical Diamond Magnetometry

Stefan,

Tan,

Vindolet

et al. 2021

Preprint

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Room-Temperature Skyrmions at Zero Field in Exchange-Biased Ultrathin Films

Cited by 36 publications

References 42 publications

Strong Interfacial Perpendicular Magnetic Anisotropy in Exchange-Biased NiO/Co/Au and NiO/Co/NiO Layered Systems

Strong Interfacial Perpendicular Magnetic Anisotropy in Exchange-Biased NiO/Co/Au and NiO/Co/NiO Layered Systems

Electron Beam Lithography of Magnetic Skyrmions

Multi-Angle Reconstruction of Domain Morphology with All-Optical Diamond Magnetometry

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