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Jeong SG, Cho SW, Song S, Oh JY, Jeong DG, Han G, Jeong HY, Mohamed AY, Noh WS, Park S, Lee JS, Lee S, Kim YM, Cho DY, Choi WS. Dimensionality Engineering of Magnetic Anisotropy from the Anomalous Hall Effect in Synthetic SrRuO 3 Crystals. NANO LETTERS 2024; 24:7979-7986. [PMID: 38829309 DOI: 10.1021/acs.nanolett.4c01536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2024]
Abstract
Magnetic anisotropy in atomically thin correlated heterostructures is essential for exploring quantum magnetic phases for next-generation spintronics. Whereas previous studies have mostly focused on van der Waals systems, here we investigate the impact of dimensionality of epitaxially grown correlated oxides down to the monolayer limit on structural, magnetic, and orbital anisotropies. By designing oxide superlattices with a correlated ferromagnetic SrRuO3 and nonmagnetic SrTiO3 layers, we observed modulated ferromagnetic behavior with the change of the SrRuO3 thickness. Especially, for three-unit-cell-thick layers, we observe a significant 1500% improvement of the coercive field in the anomalous Hall effect, which cannot be solely attributed to the dimensional crossover in ferromagnetism. The atomic-scale heterostructures further reveal the systematic modulation of anisotropy for the lattice structure and orbital hybridization, explaining the enhanced magnetic anisotropy. Our findings provide valuable insights into engineering the anisotropic hybridization of synthetic magnetic crystals, offering a tunable spin order for various applications.
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Affiliation(s)
- Seung Gyo Jeong
- Department of Physics, Sungkyunkwan University, Suwon 16419, Korea
| | - Seong Won Cho
- Center for Neuromorphic Engineering, Korea Institute of Science and Technology, Seoul 02792, Korea
| | - Sehwan Song
- Department of Physics, Pusan National University, Busan 46241, Korea
| | - Jin Young Oh
- Department of Physics, Sungkyunkwan University, Suwon 16419, Korea
| | - Do Gyeom Jeong
- Department of Physics and Photon Science, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Korea
| | - Gyeongtak Han
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Korea
| | - Hu Young Jeong
- Graduate School of Semiconductor Materials and Devices Engineering, Ulsan National Institute of Science and Technology, Ulsan 44919, Korea
| | | | - Woo-Suk Noh
- cCPM, Max Planck POSTECH/Korea Research Initiative, Pohang 37673, Korea
| | - Sungkyun Park
- Department of Physics, Pusan National University, Busan 46241, Korea
| | - Jong Seok Lee
- Department of Physics and Photon Science, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Korea
| | - Suyoun Lee
- Center for Neuromorphic Engineering, Korea Institute of Science and Technology, Seoul 02792, Korea
| | - Young-Min Kim
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Korea
| | - Deok-Yong Cho
- Department of Physics, Jeonbuk National University, Jeonju 54896, Korea
| | - Woo Seok Choi
- Department of Physics, Sungkyunkwan University, Suwon 16419, Korea
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Wang H, Zhao R, Yang C, Hong J, Li W, van Aken PA. Atomic-scale Observations of Artificially Engineered Atomic Structure in Vertically Aligned Nanocomposite Films with Emergent Multiferroicity. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2023; 29:1653-1654. [PMID: 37613958 DOI: 10.1093/micmic/ozad067.851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Affiliation(s)
- Hongguang Wang
- Max Planck Institute for Solid State Research, Stuttgart, Germany
| | - Run Zhao
- MIIT Key Laboratory of Aerospace Information Materials and Physics, College of Physics, Nanjing University of Aeronautics and Astronautics, Nanjing, China
| | - Chao Yang
- School of Aerospace Engineering, Beijing Institute of Technology, Beijing, China
| | - Jiawang Hong
- School of Aerospace Engineering, Beijing Institute of Technology, Beijing, China
| | - Weiwei Li
- MIIT Key Laboratory of Aerospace Information Materials and Physics, College of Physics, Nanjing University of Aeronautics and Astronautics, Nanjing, China
- Department of Materials Science and Metallurgy, University of Cambridge, Cambridge, UK
| | - P A van Aken
- Max Planck Institute for Solid State Research, Stuttgart, Germany
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Wang H, Laskin G, He W, Boschker H, Yi M, Braun W, Fenk B, Srot V, Mannhart J, van Aken PA. Lattice Anisotropy, Oxygen Octahedral Rotation and Tunable Magnetic Anisotropy in Patterned SrRuO3 Quantum Structures. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2023; 29:1650. [PMID: 37613913 DOI: 10.1093/micmic/ozad067.849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Affiliation(s)
- H Wang
- Max Planck Institute for Solid State Research, Stuttgart, Germany
| | - G Laskin
- Fraunhofer IPM, Freiburg, Germany
| | - W He
- Nanjing University of Aeronautics and Astronautics, Nanjing, China
| | - H Boschker
- Max Planck Institute for Solid State Research, Stuttgart, Germany
| | - M Yi
- Nanjing University of Aeronautics and Astronautics, Nanjing, China
| | - W Braun
- Max Planck Institute for Solid State Research, Stuttgart, Germany
| | - B Fenk
- Max Planck Institute for Solid State Research, Stuttgart, Germany
| | - V Srot
- Max Planck Institute for Solid State Research, Stuttgart, Germany
| | - J Mannhart
- Max Planck Institute for Solid State Research, Stuttgart, Germany
| | - P A van Aken
- Max Planck Institute for Solid State Research, Stuttgart, Germany
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Harbola V, Wu YJ, Wang H, Smink S, Parks SC, van Aken PA, Mannhart J. Self-Assembly of Nanocrystalline Structures from Freestanding Oxide Membranes. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2210989. [PMID: 36585838 DOI: 10.1002/adma.202210989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 12/19/2022] [Indexed: 06/17/2023]
Abstract
The exploration of crystalline nanostructures enhances the understanding of quantum phenomena occurring in spatially confined quantum matter and may lead to functional materials with unforeseen applications. A novel route to fabricating nanocrystalline oxide structures of exceptional quality is presented. This is achieved by utilizing a self-assembly process of ultrathin membranes composed of the desired oxide. The thermally induced self-assembly of nanocrystalline structures is driven by dewetting the oxide membranes once they are lifted off and transferred onto sapphire surfaces. In three successive steps, the process provides nanovoids, nanowires, and nanocrystals. Regardless of substrate orientation, the nanostructures are highly anisotropic in shape due to material retraction favoring low-index crystalline lattice directions of the membranes. The orientation of the nanostructures is provided precisely by the crystal lattice of the transferred membrane. The microstructure of the nanocrystals exhibits exceptional quality, characterized by a pristine crystal structure and uniform stoichiometry, both maintained all the way down to the well-developed crystalline facets. The demonstrated self-assembly process holds the potential to improve the understanding of surface diffusion phenomena at the interface of materials, which is important for advancing epitaxial growth technology and paves the way to fabricating crystalline nanostructures by the transfer and self-assembly of membranes.
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Affiliation(s)
- Varun Harbola
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569, Stuttgart, Germany
| | - Yu-Jung Wu
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569, Stuttgart, Germany
| | - Hongguang Wang
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569, Stuttgart, Germany
| | - Sander Smink
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569, Stuttgart, Germany
| | - Sarah C Parks
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569, Stuttgart, Germany
| | - Peter A van Aken
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569, Stuttgart, Germany
| | - Jochen Mannhart
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569, Stuttgart, Germany
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Mattern M, Pudell JE, Laskin G, von Reppert A, Bargheer M. Analysis of the temperature- and fluence-dependent magnetic stress in laser-excited SrRuO 3. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2021; 8:024302. [PMID: 33786338 PMCID: PMC7994007 DOI: 10.1063/4.0000072] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 02/23/2021] [Indexed: 06/07/2023]
Abstract
We use ultrafast x-ray diffraction to investigate the effect of expansive phononic and contractive magnetic stress driving the picosecond strain response of a metallic perovskite SrRuO3 thin film upon femtosecond laser excitation. We exemplify how the anisotropic bulk equilibrium thermal expansion can be used to predict the response of the thin film to ultrafast deposition of energy. It is key to consider that the laterally homogeneous laser excitation changes the strain response compared to the near-equilibrium thermal expansion because the balanced in-plane stresses suppress the Poisson stress on the picosecond timescale. We find a very large negative Grüneisen constant describing the large contractive stress imposed by a small amount of energy in the spin system. The temperature and fluence dependence of the strain response for a double-pulse excitation scheme demonstrates the saturation of the magnetic stress in the high-fluence regime.
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Affiliation(s)
- M. Mattern
- Institut für Physik und Astronomie, Universität Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam, Germany
| | | | - G. Laskin
- Max Planck Institute for Solid State Research, Heisenbergstrasse 1, 70569 Stuttgart, Germany
| | - A. von Reppert
- Institut für Physik und Astronomie, Universität Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam, Germany
| | - M. Bargheer
- Author to whom correspondence should be addressed:. URL:http://www.uni-potsdam.de/udkm
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Wang H, Srot V, Fenk B, Laskin G, Mannhart J, van Aken PA. An optimized TEM specimen preparation method of quantum nanostructures. Micron 2020; 140:102979. [PMID: 33197749 DOI: 10.1016/j.micron.2020.102979] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 10/22/2020] [Accepted: 10/22/2020] [Indexed: 11/17/2022]
Abstract
Electron transparent TEM lamella with unaltered microstructure and chemistry is the prerequisite for successful TEM explorations. Currently, TEM specimen preparation of quantum nanostructures, such as quantum dots (QDs), remains a challenge. In this work, we optimize the sample-preparation routine for achieving high-quality TEM specimens consisting of SrRuO3 (SRO) QDs grown on SrTiO3 (STO) substrates. We demonstrate that a combination of ion-beam-milling techniques can produce higher-quality specimens of quantum nanostructures compared to TEM specimens prepared by a combination of tripod polishing followed by Ar+ ion milling. In the proposed method, simultaneous imaging in a focused ion-beam device enables accurate positioning of the QD regions and assures the presence of dots in the thin lamella by cutting the sample inclined by 5° relative to the dots array. Furthermore, the preparation of TEM lamellae with several large electron-transparent regions that are separated by thicker walls effectively reduces the bending of the specimen and offers broad thin areas. The final use of a NanoMill efficiently removes the amorphous layer without introducing any additional damage.
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Affiliation(s)
- Hongguang Wang
- Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany.
| | - Vesna Srot
- Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany
| | - Bernhard Fenk
- Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany
| | - Gennadii Laskin
- Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany
| | - Jochen Mannhart
- Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany
| | - Peter A van Aken
- Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany
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