1
|
Marchiori E, Romagnoli G, Schneider L, Gross B, Sahafi P, Jordan A, Budakian R, Baral PR, Magrez A, White JS, Poggio M. Imaging magnetic spiral phases, skyrmion clusters, and skyrmion displacements at the surface of bulk Cu 2OSeO 3. COMMUNICATIONS MATERIALS 2024; 5:202. [PMID: 39351280 PMCID: PMC11438600 DOI: 10.1038/s43246-024-00647-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2024] [Accepted: 09/19/2024] [Indexed: 10/04/2024]
Abstract
Surfaces - by breaking bulk symmetries, introducing roughness, or hosting defects - can significantly influence magnetic order in magnetic materials. Determining their effect on the complex nanometer-scale phases present in certain non-centrosymmetric magnets is an outstanding problem requiring high-resolution magnetic microscopy. Here, we use scanning SQUID microscopy to image the surface of bulk Cu2OSeO3 at low temperature and in a magnetic field applied along100 . Real-space maps measured as a function of applied field reveal the microscopic structure of the magnetic phases and their transitions. In low applied field, we observe a magnetic texture consistent with an in-plane stripe phase, pointing to the existence of a distinct surface state. In the low-temperature skyrmion phase, the surface is populated by clusters of disordered skyrmions, which emerge from rupturing domains of the tilted spiral phase. Furthermore, we displace individual skyrmions from their pinning sites by applying an electric potential to the scanning probe, thereby demonstrating local skyrmion control at the surface of a magnetoelectric insulator.
Collapse
Affiliation(s)
| | | | - Lukas Schneider
- Department of Physics, University of Basel, Basel, Switzerland
- Swiss Nanoscience Institute, University of Basel, Basel, Switzerland
| | - Boris Gross
- Department of Physics, University of Basel, Basel, Switzerland
| | - Pardis Sahafi
- Department of Physics and Astronomy, University of Waterloo, Waterloo, Canada
- Institute for Quantum Computing, University of Waterloo, Waterloo, Canada
- Present Address: National Research Council, Ottawa, Canada
| | - Andrew Jordan
- Department of Physics and Astronomy, University of Waterloo, Waterloo, Canada
- Institute for Quantum Computing, University of Waterloo, Waterloo, Canada
| | - Raffi Budakian
- Department of Physics and Astronomy, University of Waterloo, Waterloo, Canada
- Institute for Quantum Computing, University of Waterloo, Waterloo, Canada
| | - Priya R. Baral
- Laboratory for Neutron Scattering and Imaging, PSI Center for Neutron and Muon Sciences, Paul Scherrer Institute, Villigen PSI, Switzerland
- Institute of Physics, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
- Present Address: Department of Applied Physics and Quantum-Phase Electronics Center, University of Tokyo, Tokyo, Japan
| | - Arnaud Magrez
- Institute of Physics, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Jonathan S. White
- Laboratory for Neutron Scattering and Imaging, PSI Center for Neutron and Muon Sciences, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Martino Poggio
- Department of Physics, University of Basel, Basel, Switzerland
- Swiss Nanoscience Institute, University of Basel, Basel, Switzerland
| |
Collapse
|
2
|
Magnetic Structure and Strain State in Fe/V Superlattices Studied by 57Fe+ Emission and Conversion Electron Mössbauer Spectroscopy. CRYSTALS 2022. [DOI: 10.3390/cryst12070961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The magnetic properties of the Fe/V superlattices were studied by conventional Conversion Electron Mössbauer Spectroscopy (CEMS) and online 57Fe+ emission Mössbauer Spectroscopy (eMS) at room temperature (RT) at ISOLDE/CERN. The unique depth-enhanced sensitivity and ultradiluted regime of the probe atoms adopted in this eMS facility enabled the investigation of the magnetic structures and the strain state in the superlattice layers and at the interfaces. The magnetic spectra of the superlattices were found to depend on both the local lattice environment and the strain state of the Fe-lattices. The magnetic polarisation in the V-layers or at the interfaces was not detected at RT. Spectral broadening was evident in the single line component of the eMS due to Fe ions substituted at V-lattice sites in the V-layers of the superlattice, attributable to the lattice strain in the V-layers. Our study demonstrate that with the online eMS technique the effects of the strain state of the superlattice on the magnetic properties of the Fe-layer in the Fe/V multilayer structures can be detected.
Collapse
|
3
|
Navarro E, González MU, Béron F, Tejo F, Escrig J, García-Martín JM. Large-Area Nanopillar Arrays by Glancing Angle Deposition with Tailored Magnetic Properties. NANOMATERIALS 2022; 12:nano12071186. [PMID: 35407304 PMCID: PMC9000416 DOI: 10.3390/nano12071186] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 03/27/2022] [Accepted: 03/28/2022] [Indexed: 02/04/2023]
Abstract
Ferromagnetic films down to thicknesses of tens of nanometers and composed by polycrystalline Fe and Fe2O3 nanopillars are grown in large areas by glancing angle deposition with magnetron sputtering (MS-GLAD). The morphological features of these films strongly depend on the growth conditions. Vertical or tilted nanopillars have been fabricated depending on whether the substrate is kept rotating azimuthally during deposition or not, respectively. The magnetic properties of these nanopillars films, such as hysteresis loops squareness, adjustable switching fields, magnetic anisotropy and coercivity, can be tuned with the specific morphology. In particular, the growth performed through a collimator mask mounted onto a not rotating azimuthally substrate produces almost isolated well-defined tilted nanopillars that exhibit a magnetic hardening. The first-order reversal curves diagrams and micromagnetic simulations revealed that a growth-induced uniaxial anisotropy, associated with an anisotropic surface morphology produced by the glancing angle deposition in the direction perpendicular to the atomic flux, plays an important role in the observed magnetic signatures. These results demonstrate the potential of the MS-GLAD method to fabricate nanostructured films in large area with tailored structural and magnetic properties for technological applications.
Collapse
Affiliation(s)
- Elena Navarro
- Instituto de Magnetismo Aplicado, Universidad Complutense de Madrid-ADIF-CSIC, P.O. Box 155, Las Rozas, 28230 Madrid, Spain
- Departamento de Física de Materiales, Universidad Complutense de Madrid, 28040 Madrid, Spain
- Correspondence:
| | - María Ujué González
- Instituto de Micro y Nanotecnología, IMN-CNM, CSIC (CEI UAM+CSIC), Isaac Newton 8, Tres Cantos, 28760 Madrid, Spain; (M.U.G.); (J.M.G.-M.)
| | - Fanny Béron
- Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas (UNICAMP), Campinas 13083-859, SP, Brazil;
| | - Felipe Tejo
- Departamento de Física, Facultad de Ciencia, Universidad de Santiago de Chile (USACH), Santiago 9170124, Chile; (F.T.); (J.E.)
- Instituto de Ciencia de Materiales de Madrid, Cantoblanco, 28049 Madrid, Spain
| | - Juan Escrig
- Departamento de Física, Facultad de Ciencia, Universidad de Santiago de Chile (USACH), Santiago 9170124, Chile; (F.T.); (J.E.)
- Center for the Development of Nanoscience and Nanotechnology (CEDENNA), Santiago 9170124, Chile
| | - José Miguel García-Martín
- Instituto de Micro y Nanotecnología, IMN-CNM, CSIC (CEI UAM+CSIC), Isaac Newton 8, Tres Cantos, 28760 Madrid, Spain; (M.U.G.); (J.M.G.-M.)
| |
Collapse
|
4
|
Fei Z, Huang B, Malinowski P, Wang W, Song T, Sanchez J, Yao W, Xiao D, Zhu X, May AF, Wu W, Cobden DH, Chu JH, Xu X. Two-dimensional itinerant ferromagnetism in atomically thin Fe 3GeTe 2. NATURE MATERIALS 2018; 17:778-782. [PMID: 30104669 DOI: 10.1038/s41563-018-0149-7] [Citation(s) in RCA: 432] [Impact Index Per Article: 72.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Accepted: 07/13/2018] [Indexed: 05/20/2023]
Abstract
Discoveries of intrinsic two-dimensional (2D) ferromagnetism in van der Waals (vdW) crystals provide an interesting arena for studying fundamental 2D magnetism and devices that employ localized spins1-4. However, an exfoliable vdW material that exhibits intrinsic 2D itinerant magnetism remains elusive. Here we demonstrate that Fe3GeTe2 (FGT), an exfoliable vdW magnet, exhibits robust 2D ferromagnetism with strong perpendicular anisotropy when thinned down to a monolayer. Layer-number-dependent studies reveal a crossover from 3D to 2D Ising ferromagnetism for thicknesses less than 4 nm (five layers), accompanied by a fast drop of the Curie temperature (TC) from 207 K to 130 K in the monolayer. For FGT flakes thicker than ~15 nm, a distinct magnetic behaviour emerges in an intermediate temperature range, which we show is due to the formation of labyrinthine domain patterns. Our work introduces an atomically thin ferromagnetic metal that could be useful for the study of controllable 2D itinerant ferromagnetism and for engineering spintronic vdW heterostructures5.
Collapse
Affiliation(s)
- Zaiyao Fei
- Department of Physics, University of Washington, Seattle, WA, USA
| | - Bevin Huang
- Department of Physics, University of Washington, Seattle, WA, USA
| | - Paul Malinowski
- Department of Physics, University of Washington, Seattle, WA, USA
| | - Wenbo Wang
- Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, USA
| | - Tiancheng Song
- Department of Physics, University of Washington, Seattle, WA, USA
| | - Joshua Sanchez
- Department of Physics, University of Washington, Seattle, WA, USA
| | - Wang Yao
- Department of Physics and Center of Theoretical and Computational Physics, University of Hong Kong, Hong Kong, China
| | - Di Xiao
- Department of Physics, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Xiaoyang Zhu
- Department of Chemistry, Columbia University, New York, NY, USA
| | - Andrew F May
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Weida Wu
- Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, USA
| | - David H Cobden
- Department of Physics, University of Washington, Seattle, WA, USA
| | - Jiun-Haw Chu
- Department of Physics, University of Washington, Seattle, WA, USA.
| | - Xiaodong Xu
- Department of Physics, University of Washington, Seattle, WA, USA.
- Department of Materials Science and Engineering, University of Washington, Seattle, WA, USA.
| |
Collapse
|
5
|
|
6
|
Pierron-Bohnes V, Tamion A, Tournus F, Dupuis V. Magnetism of Low-Dimension Alloys. NANOALLOYS 2012. [DOI: 10.1007/978-1-4471-4014-6_9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
|