A5014667839- Magnetic properties of thin films
- Physics of Superconductivity and Magnetism
- Quantum and electron transport phenomena
- Theoretical and Computational Physics
- Characterization and Applications of Magnetic Nanoparticles
- Magnetic Properties and Applications
- Advanced Memory and Neural Computing
- Advanced Condensed Matter Physics
- Oral and Maxillofacial Pathology
- Magneto-Optical Properties and Applications
- Magnetic and transport properties of perovskites and related materials
- Bone health and treatments
- Mechanical and Optical Resonators
- ZnO doping and properties
- Multiferroics and related materials
- Topological Materials and Phenomena
- Bone Tumor Diagnosis and Treatments
- Medical and Biological Sciences
- Metallic Glasses and Amorphous Alloys
- Cancer Diagnosis and Treatment
- Graphene research and applications
- Geomagnetism and Paleomagnetism Studies
- Magnetic Field Sensors Techniques
- Bone and Joint Diseases
- Salivary Gland Tumors Diagnosis and Treatment
ETH Zurich
2023-2025
École Normale Supérieure - PSL
2022-2024
Université Grenoble Alpes
2024
Institut Néel
2024
Laboratoire de Physique de l'ENS
2022-2024
Laboratoire Albert Fert
2017-2023
Université Paris-Saclay
2017-2023
Centre National de la Recherche Scientifique
2017-2023
Université Paris Cité
2023
Université Paris Sciences et Lettres
2023
Magnetic skyrmions are nanoscale windings of the spin configuration that hold great promise for technology due to their topology-related properties and extremely reduced sizes. After recent observation at room temperature sub-100 nm stabilized by interfacial chiral interaction in magnetic multilayers, several pending questions remain be solved, notably about means nucleate individual compact or exact nature motion. In this study, a method leading formation micrometer-sized nanotrack using...
Noncollinear spin textures in ferromagnetic ultrathin films are currently the subject of renewed interest since discovery interfacial Dzyaloshinskii-Moriya interaction (DMI). This antisymmetric exchange selects a given chirality for and allows stabilizing configurations with nontrivial topology including chiral domain walls (DWs) magnetic skyrmions. Moreover, it has many crucial consequences on dynamical properties these topological structures. In recent years, study noncollinear been...
The Hanle magnetoresistance is a telltale signature of spin precession in nonmagnetic conductors, which strong spin-orbit coupling generates edge accumulation via the Hall effect. Here, we report existence large single layers Mn with weak coupling, attribute to orbital simultaneous observation sizable and vanishing small BiYIG/Mn bilayers corroborates origin both effects. We estimate an angle 0.016, relaxation time 2 ps diffusion length order nm disordered Mn. Our findings indicate that...
The magnitude of spin-orbit torque (SOT), exerted to a ferromagnet (FM) from an adjacent heavy metal (HM), strongly depends on the amount spin currents absorbed in FM. We exploit large absorption at Ru interface manipulate SOTs HM/FM/Ru multilayers. While FM thickness is smaller than its dephasing length 1.2 nm, top layer largely boosts into and substantially enhances strength SOT acting Spin-pumping experiments induced by ferromagnetic resonance support our conclusions that observed...
The recently discovered spin-orbit torque could be used to flip bits in spintronic devices. authors investigate its less-studied component, the fieldlike torque, and find that with help of this piece, there is no need for an external magnetic field achieve deterministic reversal magnetization. In principle solves one critical issues spintronics, promising applications terms speed energy efficiency.
Orbital currents have recently emerged as a promising tool to achieve electrical control of the magnetization in thin-film ferromagnets. Efficient orbital-to-spin conversion is required order torque magnetization. Here, we show that injection an orbital current ferrimagnetic ${\mathrm{Gd}}_{\mathrm{y}}{\mathrm{Co}}_{100\ensuremath{-}\mathrm{y}}$ alloy generates strong torques whose sign and magnitude can be tuned by changing Gd content temperature. The effective spin-orbital Hall angle...
The spin orbit torques (SOTs) in perpendicularly magnetized Co-Ni multilayers sandwiched between two heavy metals (HM) have been studied. By exploring various HM materials, we show an efficient enhancement or cancellation of the total SOT, depending on combination materials. maximum SOT effective field is obtained Pt/Co-Ni/W heterostructures. We also model our double system and that Hall angle has a peak value at certain thicknesses. Measuring for W thicknesses confirms up to 0.45 system.
Chirality in condensed matter has recently become a topic of the utmost importance because its significant role understanding and mastering large variety new fundamental physical mechanisms. Versatile experimental approaches, capable to reveal easily exact winding order parameters, are therefore essential. Here we report x-ray resonant magnetic scattering as straightforward tool directly properties chiral systems. We show that it can straightforwardly unambiguously determine main...
Skyrmions in ultrathin ferromagnetic metal (FM)/heavy (HM) multilayer systems produced by conventional sputtering methods have recently generated huge interest due to their applications the field of spintronics. The sandwich structure with two correctly-chosen heavy layers provides an additive interfacial exchange interaction which promotes domain wall or skyrmion spin textures that are Néel character and a fixed chirality. Lorentz transmission electron microscopy (TEM) is high resolution...
The Dzyaloshinskii-Moriya interaction (DMI), which is essential for the stabilization of topologically non-trivial chiral magnetic textures such as skyrmions, particularly strong in heterostructures ultra-thin materials and heavy elements. We explore by density-functional theory calculations possibility to modify properties at Co/Pt interfaces with chemical disorder. In these systems, we find a particular robustness DMI against intermixing. Upon dusting interface third element (all 4d...
Magnetic skyrmions are particle-like deformations in a magnetic texture. They have great potential as information carriers spintronic devices because of their interesting topological properties and favorable motion under spin currents. A new method nucleating at nanoscale defect sites, created controlled manner with focused ion beam irradiation, polycrystalline multilayer samples an interfacial Dzyaloshinskii-Moriya interaction, is reported. This has three notable advantages: 1) localization...
Antiferromagnetic materials are promising platforms for next-generation spintronics owing to their fast dynamics and high robustness against parasitic magnetic fields. However, nanoscale imaging of the order in such with zero net magnetization remains a major experimental challenge. Here we show that non-collinear antiferromagnetic spin textures can be imaged by probing noise they locally produce via thermal populations magnons. To this end, perform nanoscale, all-optical relaxometry...
Spin pumping can generate spin current by driving a magnetic system into resonance, phenomenon that be electrically detected via the inverse Hall effect. However, efficiency of generation has remained limited, compared to spin-to-charge conversion. This work systematically demonstrates an innovative technique for probing propagating waves and creating with high efficiency, mediated flat-band magnons excited broad wave vectors. These findings lay promising foundation further experiments waves.
Charge-spin interconversion processes underpin the generation of spin-orbit torques in magnetic/nonmagnetic bilayers. However, efficient sources spin currents such as 5
Microwave spectroscopies are central to the investigation of magnetic systems by enabling identification dynamical resonance modes and providing quantitative information on key parameters. Experiments magnetization dynamics based inductive microwave techniques usually rely either field-modulated power detection or phase-resolved using a vector network analyzer. While these two approaches bring separate advantages, they have rarely been combined together. In this work, we develop customized...
We report the detection of pure orbital currents generated by both coherent and thermal magnons in magnetic insulator Bi-doped yttrium iron garnet (BiYIG). The pumping spin is jointly investigated nanodevices made naturally oxidized Cu, Pt, Cr. absence charge conduction BiYIG negligible spin-to-charge conversion Cu allows us to disambiguate current contribution. Comparative measurements on YIG show that origin BiYIG/oxidized dynamics magnetization insulator. In Cr, signal dominated negative...
Magnetic skyrmions (arrangements of spins featuring topological properties) are candidates to implement information bits in devices for combined data storage and logic processing. A prerequisite is the further optimization host magnetic multilayers, obtain sufficiently stable mobile below 10 nm size. This study develops an extensive model allowing analysis or prediction their size, structure, dynamical behavior. establishes guidelines optimizing multilayer properties on way applications skyrmions.
Chiral magnetic textures in ultrathin perpendicularly magnetised multilayer film stacks with an interfacial Dzyaloshinskii-Moriya interaction have been the focus of much research recently. The chirality associated broken inversion symmetry at interface between ferromagnetic layer and a heavy metal large spin-orbit coupling supports homochiral Néel domain walls hedgehog (Néel) skyrmions. Under torques these type structures are predicted, measured, to move high velocities. However recent...
Inversion-asymmetric stacks of metallic magnetic layers have often been exploited to control the chiral noncollinear ordering their moments. Here, authors investigate interfacial aspects Dzyaloshinskii-Moriya interaction, giving rise this ordering, and quantify its contributions within a couple atomic layers. This observation is further supported by first-principles calculations. The confirmation short spatial extent DMI expected enable synthesis dense multilayers offer possibilities for...
The actual mechanisms occurring at interfaces underlying the Dzyaloshinskii-Moriya interaction (DMI) remain a question in nanomagnetism. In this study, we investigate origin of interfacial DMI, aiming estimating how independent DMI contributions two FM layer are and what their relative weight effective amplitude is. To aim, explore correlation between metal properties, namely, atomic number, electronegativity, work function $M$. A clear linear relationship is found difference $\mathrm{Co}/M$...
We experimentally study the thermoelectrical signature of individual skyrmions in chiral $\mathrm{Pt}/\mathrm{Co}/\mathrm{Ru}$ multilayers. Using a combination controlled nucleation, single skyrmion annihilation, and magnetic field dependent measurements thermoelectric is characterized. The observed explained by anomalous Nernst effect skyrmion's spin structure. Possible topological contributions to are discussed. Such characterization allows for noninvasive detection counting enables...
Room-temperature stabilization of skyrmions in magnetic multilayered systems results from a fine balance between several interactions, namely, symmetric and antisymmetric exchange, dipolar interaction perpendicular anisotropy as well as, most cases, Zeeman through an applied external field. Such field-driven approach is, however, not compatible with the anticipated skyrmion based applications, e.g., memories logic or neuromorphic computing, which motivates reduction cancellation field...