A5053102330- Magnetic properties of thin films
- Advanced Condensed Matter Physics
- Theoretical and Computational Physics
- Physics of Superconductivity and Magnetism
- Graphene research and applications
- Quantum and electron transport phenomena
- 2D Materials and Applications
- Surface and Thin Film Phenomena
- Electron and X-Ray Spectroscopy Techniques
- Magnetic Properties and Applications
- Magnetic and transport properties of perovskites and related materials
- ZnO doping and properties
- Topological Materials and Phenomena
- Multiferroics and related materials
- Quantum many-body systems
- Diamond and Carbon-based Materials Research
- Photocathodes and Microchannel Plates
- Perovskite Materials and Applications
- Semiconductor Quantum Structures and Devices
- Cellular Automata and Applications
- Advanced Chemical Physics Studies
- Advanced Electron Microscopy Techniques and Applications
- Metallic Glasses and Amorphous Alloys
- Magnetic Properties of Alloys
- Agriculture and Rural Development Research
Université Grenoble Alpes
2016-2025
Institut Néel
2016-2025
Institut polytechnique de Grenoble
2017-2025
Centre National de la Recherche Scientifique
2015-2024
University of Tsukuba
2017
Spintronique et Technologie des Composants
2017
CEA Grenoble
2017
Institut Nanosciences et Cryogénie
2017
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2017
Kansai University
2017
Topological protection is an elegant way of warranting the integrity quantum and nanosized systems. In magnetism one example Bloch-point, a peculiar object implying local vanishing magnetization within ferromagnet. Its existence had been postulated described theoretically since several decades, however it has never observed. We con rm experimentally Bloch points, imaged domain walls in cylindrical magnetic nanowires, combining surface transmission XMCD-PEEM microscopy. This opens to...
We report strongly enhanced perpendicular magnetic anisotropy (PMA) of Co films by graphene coating from both first-principles and experiments. Our calculations show that can dramatically boost the surface up to twice value its pristine counterpart extend out-of-plane effective unprecedented thickness 25~\AA. These findings are supported our experiments on grown Ir substrate. Furthermore, we layer-resolved orbital-hybridization-resolved analysis which help understanding physical mechanisms...
Magnetic frustration effects in artificial kagome arrays of nanomagnets are investigated using x-ray photoemission electron microscopy and Monte Carlo simulations. Spin configurations demagnetized networks reveal unambiguous signatures long range, dipolar interaction between the nanomagnets. As soon as system enters spin ice manifold, model captures observed physics, while short range fails.
Abstract Geometrical frustration in magnetic materials often gives rise to exotic, low-temperature states of matter, such as the ones observed spin ices. Here we report imaging a thermally active artificial ice that reveal fingerprints fragmentation process. This corresponds splitting degree freedom into two channels and is evidenced both real reciprocal space. Furthermore, internal organization interpreted within framework hybrid spin–charge model directly emerges from parent kagome dipolar...
The recent discovery of magnetic van der Waals (vdW) materials triggered a wealth investigations in science and now offers genuinely new prospects for both fundamental applied research. Although the catalog vdW ferromagnets is rapidly expanding, most them have Curie temperature below 300 K, notable disadvantage potential applications. Combining element-selective X-ray imaging force microscopy, we resolve at room domains domain walls micron-sized flakes CrTe2 ferromagnet. Flux-closure...
Spin-polarized low-energy electron microscopy (SPLEEM) is a technique for imaging magnetic microstructures at surfaces and in thin films. In this article, principles, advantages limitations of SPLEEM are reviewed. Several recent studies illustrate how can be used to investigate spin reorientation transition phenomena, determine domain configurations low-dimensional structures, or explore physics couplings layered systems. The work highlights the capability reveal situ real time quantitative...
We present a combined analytical and numerical micromagnetic study of the equilibrium energy, size shape anti-skyrmionic magnetic configurations. Anti-skyrmions can be stabilized when Dzyaloshinskii-Moriya interaction has opposite signs along two orthogonal in-plane directions, breaking circular symmetry. compare anti-skyrmions skyrmions that are respectively in environments with anisotropic isotropic interaction, but same strength interactions.When dipolar interactions neglected skyrmion...
Magnetic skyrmions and bubbles, observed in ferromagnetic thin films with perpendicular magnetic anisotropy, are topological solitons which differ by their characteristic size the balance energies at origin of stabilisation. However, these two spin textures have same topology a continuous transformation between them is allowed. In present work, we derive an analytical model to explore skyrmion-bubble transition. We evidence region parameter space where both soliton solutions coexist close...
The extended carbon–metal contact in graphene–metal hybrids opens new avenues for manipulating the properties of both constituents hybrid and combining functionalities each them. We developed a two-step ultrahigh vacuum route to fabricate high-quality nanometer-thick metal films having abrupt interfaces, sandwiched between protective graphene layer its substrate, using chemical vapor deposition intercalation made effective at mild temperatures. demonstrate functional systems with...
Abstract Magnetic domain structure and spin-dependent reflectivity measurements on cobalt thin films intercalated at the graphene/Ir(111) interface are investigated using spin-polarised low-energy electron microscopy. We find that graphene-covered have surprising magnetic properties. Vectorial imaging of domains reveals an unusually gradual thickness-dependent spin reorientation transition, in which magnetisation rotates from out-of-the-film plane to in-plane direction by less than 10° per...
We report a new class of algebraic spin liquids, in which the macroscopically degenerate ground state manifold is not Coulombic, like ices, but Amp\`ere-like. The local constraint characterizing an Amp\`ere phase Gauss law, rather i.e., condition on curl magnetization vector field and its divergence. As consequence, excitations evolving such are magnetically charged scalar quasiparticles, so-called magnetic monopoles Coulomb phases, instead vectorial loops (or fictional current lines)....
Lamellar crystalline materials, whose layers are bond by van der Waals forces, can be stacked to form ultrathin artificial heterostructures, and in particular vertical magnetic junctions when some of the materials (ferro)magnetic. Here, using room temperature ferromagnet 1$T$-CrTe$_2$, we report a method for patterning lateral junctions. Exploiting heat-induced phase transformation material into Cr$_x$Te$_y$ compounds ($x/y>1/2$), use local laser heating imprint patterns at micron-scale....
Micromagnetic properties of monopoles in artificial kagome spin ice systems are investigated using numerical simulations. We show that micromagnetics brings additional complexity into the physics these is, by essence, absent models: addition to a fractionalized classical magnetic charge, chiral at remanence. Our simulations predict chirality can be controlled without altering their charge state. This breaks vertex symmetry and triggers directional motion monopole under an applied field....
Magnetic frustration effects in artificial kagome arrays of nanomagnets with out-of-plane magnetization are investigated using magnetic force microscopy and Monte Carlo simulations. Experimental theoretical results compared to those found for the spin ice which have in-plane magnetization. In contrast what has been recently reported, we demonstrate that long-range (i.e., beyond nearest-neighbor) dipolar interactions between cannot be neglected when describing configurations observed after...
We have investigated the low-temperature thermodynamic properties of dipolar kagome Ising antiferromagnet using at-equilibrium Monte Carlo simulations, in quest for ground-state manifold. In spite limitations a single spin-flip approach, we managed to identify certain ordering patterns regime and propose candidate this unknown state. This novel configuration presents some intriguing features passes several test-criteria, making it very likely choice long-range order antiferromagnet.
Using low-energy electron microscopy, we study Co intercalation under graphene grown on Ir(111). Depending the rotational domain of which it is deposited, found intercalated at different locations. While observed preferentially substrate step edges below certain domains, mostly close to wrinkles other domains. These results indicate that curved regions (near atomic steps and wrinkles) sheet facilitate suggest strength graphene/Ir interaction determines pathway energetically more favorable.
Van der Waals magnetic materials are building blocks for novel kinds of spintronic devices and playgrounds exploring collective phenomena down to the two-dimensional limit. Chromium–tellurium compounds relevant in this perspective. In particular, 1T phase CrTe2 has been argued have a Curie temperature above 300 K, rare desirable property class lamellar materials, making it candidate practical applications. However, recent literature reveals strong variability reported properties, including...
Current-induced magnetic domain wall motion at zero field is observed in the permalloy layer of a spin-valve-based nanostripe using photoemission electron microscopy. The movement hampered by pinning sites, but between them high velocities (exceeding 150 m/s) are obtained for current densities well below 1012 A/m2, suggesting that these trilayer systems promising applications devices case controlled positions. Vertical spin currents structures provide potential explanation increase velocity...
Spin liquids are correlated, disordered states of matter that fluctuate even at low temperatures. Experimentally, the extensive degeneracy characterizing their low-energy manifold is expected to be lifted, for example, because dipolar interactions, leading an ordered ground state absolute zero. However, this not what usually observed, and many systems, whether they chemically synthesized or nanofabricated, dynamically freeze before magnetic ordering sets in. In artificial realizations highly...