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Stramaglia F, Panchal G, Nolting F, Vaz CAF. Fully Magnetically Polarized Ultrathin La 0.8Sr 0.2MnO 3 Films. ACS APPLIED MATERIALS & INTERFACES 2024; 16:4138-4149. [PMID: 38216138 PMCID: PMC10811626 DOI: 10.1021/acsami.3c14031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 12/18/2023] [Accepted: 12/18/2023] [Indexed: 01/14/2024]
Abstract
We report the observation of fully magnetically polarized ultrathin La0.8Sr0.2MnO3 films by using LaMnO3 and La0.45Sr0.55MnO3 buffer layers grown epitaxially on SrTiO3(001) substrates by molecular beam epitaxy. Specifically, we show that La0.8Sr0.2MnO3 films grown on 12-unit-cell LaMnO3 have bulk-like magnetic moments starting from a single unit cell thickness, while for the 15-unit-cell La0.45Sr0.55MnO3 buffer layer, the La0.8Sr0.2MnO3 transitions from an antiferromagnetic state to a fully spin-polarized ferromagnetic state at 4 unit cells. The magnetic results are confirmed by X-ray magnetic circular dichroism, while linear dichroic measurements carried out for the La0.8Sr0.2MnO3/La0.45Sr0.55MnO3 series show the presence of an orbital reorganization at the transition from the antiferromagnetic to ferromagnetic state corresponding to a change from a preferred in-plane orbital hole occupancy, characteristic of the A-type antiferromagnetic state of La0.45Sr0.55MnO3, to preferentially out of plane. We interpret our findings in terms of the different electronic charge transfers between the adjacent layers, confined to the unit cell in the case of insulating LaMnO3 and extended to a few unit cells in the case of conducting La0.45Sr0.55MnO3. Our work demonstrates an approach to growing ultrathin mixed-valence manganite films that are fully magnetically polarized from the single unit cell, paving the way to fully exploring the unique electronic properties of this class of strongly correlated oxide materials.
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Affiliation(s)
| | - Gyanendra Panchal
- Swiss Light Source, Paul Scherrer Institut, Villigen 5232, Switzerland
| | - Frithjof Nolting
- Swiss Light Source, Paul Scherrer Institut, Villigen 5232, Switzerland
| | - Carlos A. F. Vaz
- Swiss Light Source, Paul Scherrer Institut, Villigen 5232, Switzerland
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Non-universal current flow near the metal-insulator transition in an oxide interface. Nat Commun 2021; 12:3311. [PMID: 34083533 PMCID: PMC8175561 DOI: 10.1038/s41467-021-23393-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 04/21/2021] [Indexed: 11/12/2022] Open
Abstract
In systems near phase transitions, macroscopic properties often follow algebraic scaling laws, determined by the dimensionality and the underlying symmetries of the system. The emergence of such universal scaling implies that microscopic details are irrelevant. Here, we locally investigate the scaling properties of the metal-insulator transition at the LaAlO3/SrTiO3 interface. We show that, by changing the dimensionality and the symmetries of the electronic system, coupling between structural and electronic properties prevents the universal behavior near the transition. By imaging the current flow in the system, we reveal that structural domain boundaries modify the filamentary flow close to the transition point, preventing a fractal with the expected universal dimension from forming. Macroscopic properties usually follow algebraic scaling laws near phase transitions. Here, the authors investigate the scaling properties of the metal‐insulator transition at the LaAlO3/SrTiO3 interface, finding that coupling between structural and electronic properties prevents the universal behavior.
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Sinha UK, Das B, Padhan P. Interfacial reconstruction in La 0.7Sr 0.3MnO 3 thin films: giant low-field magnetoresistance. NANOSCALE ADVANCES 2020; 2:2792-2799. [PMID: 36132380 PMCID: PMC9418895 DOI: 10.1039/d0na00287a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Accepted: 05/07/2020] [Indexed: 06/12/2023]
Abstract
Herein, interfacial reconstruction in a series of La0.7Sr0.3MnO3 (LSMO) films grown on a (001) oriented LaAlO3 (LAO) substrate using the pulsed plasma sputtering technique is demonstrated. X-ray diffraction studies suggested that the LSMO film on LAO was stabilized in a tetragonal structure, which was relaxed in-plane and strained along the out-of-plane direction. The interfacial reconstruction of the LSMO-LAO interface due to the reorientation of the Mn ion spin induced spin-glass behavior due to the presence of non-collinear Mn ion spins. Consequently, the interface effect was observed on the Curie temperature, temperature-dependent resistivity, metal-to-semiconductor transition temperature, and magnetoresistance (MR). At a magnetic field of 7 T, MR decreased from 99.8% to 7.69% as the LSMO film thickness increased from 200 Å to 500 Å. A unique characteristic of the LSMO films is the large low-field MR after a decrease in the field from the maximum field. The observed temperature-dependent magnetization and low-temperature resistivity upturn of the LSMO films grown on LAO provide direct evidence that the low-field MR is due to the non-collinear interfacial spins of Mn. The present work demonstrates the great potential of interface and large low-field MR, which might advance the fundamental applications of orbital physics and spintronics.
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Affiliation(s)
- Umesh Kumar Sinha
- Department of Physics, Indian Institute of Technology Madras Chennai 600036 India
| | - Bibekananda Das
- Department of Physics, Indian Institute of Technology Madras Chennai 600036 India
| | - Prahallad Padhan
- Department of Physics, Indian Institute of Technology Madras Chennai 600036 India
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van Thiel TC, Fowlie J, Autieri C, Manca N, Šiškins M, Afanasiev D, Gariglio S, Caviglia AD. Coupling Lattice Instabilities Across the Interface in Ultrathin Oxide Heterostructures. ACS MATERIALS LETTERS 2020; 2:389-394. [PMID: 32478332 PMCID: PMC7254603 DOI: 10.1021/acsmaterialslett.9b00540] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 03/09/2020] [Indexed: 06/11/2023]
Abstract
Oxide heterointerfaces constitute a rich platform for realizing novel functionalities in condensed matter. A key aspect is the strong link between structural and electronic properties, which can be modified by interfacing materials with distinct lattice symmetries. Here, we determine the effect of the cubic-tetragonal distortion of SrTiO3 on the electronic properties of thin films of SrIrO3, a topological crystalline metal hosting a delicate interplay between spin-orbit coupling and electronic correlations. We demonstrate that below the transition temperature at 105 K, SrIrO3 orthorhombic domains couple directly to tetragonal domains in SrTiO3. This forces the in-phase rotational axis to lie in-plane and creates a binary domain structure in the SrIrO3 film. The close proximity to the metal-insulator transition in ultrathin SrIrO3 causes the individual domains to have strongly anisotropic transport properties, driven by a reduction of bandwidth along the in-phase axis. The strong structure-property relationships in perovskites make these compounds particularly suitable for static and dynamic coupling at interfaces, providing a promising route towards realizing novel functionalities in oxide heterostructures.
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Affiliation(s)
- Thierry C. van Thiel
- Kavli
Institute of Nanoscience, Delft University
of Technology, Lorentzweg 1, 2628 CJ Delft, Netherlands
| | - Jennifer Fowlie
- Department
of Quantum Matter Physics, University of
Geneva, 24 Quai Ernest-Ansermet, 1211 Genève 4, Switzerland
| | - Carmine Autieri
- International
Research Centre MagTop, Institute of Physics, Polish Academy of Sciences, Aleja Lotników 32/46, PL-02668 Warsaw, Poland
- Consiglio
Nazionale delle Ricerche, Istituto Superconduttori,
Materiali Innovativi e Dispositivi (CNR-SPIN), c/o Università G. D’Annunzio, I-66100 Chieti, Italy
| | - Nicola Manca
- Kavli
Institute of Nanoscience, Delft University
of Technology, Lorentzweg 1, 2628 CJ Delft, Netherlands
| | - Makars Šiškins
- Kavli
Institute of Nanoscience, Delft University
of Technology, Lorentzweg 1, 2628 CJ Delft, Netherlands
| | - Dmytro Afanasiev
- Kavli
Institute of Nanoscience, Delft University
of Technology, Lorentzweg 1, 2628 CJ Delft, Netherlands
| | - Stefano Gariglio
- Department
of Quantum Matter Physics, University of
Geneva, 24 Quai Ernest-Ansermet, 1211 Genève 4, Switzerland
| | - Andrea D. Caviglia
- Kavli
Institute of Nanoscience, Delft University
of Technology, Lorentzweg 1, 2628 CJ Delft, Netherlands
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Zhang B, Wu L, Yin WG, Sun CJ, Yang P, Venkatesan T, Chen J, Zhu Y, Chow GM. Interfacial Coupling-Induced Ferromagnetic Insulator Phase in Manganite Film. NANO LETTERS 2016; 16:4174-4180. [PMID: 27276032 DOI: 10.1021/acs.nanolett.6b01056] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Interfaces with subtle differences in atomic and electronic structures in perovskite ABO3 heterostructures often yield intriguingly different properties, yet their exact roles remain elusive. Here, we report an integrated study of unusual transport, magnetic, and structural properties of Pr0.67Sr0.33MnO3 film on SrTiO3 substrate. The variations in the out-of-plane lattice constant and BO6 octahedral rotation across the Pr0.67Sr0.33MnO3/SrTiO3 interface strongly depend on the thickness of the Pr0.67Sr0.33MnO3 film. In the 12 nm film, a new interface-sensitive ferromagnetic polaronic insulator (FI') phase is formed during the cubic-to-tetragonal phase transition of SrTiO3, apparently due to the enhanced electron-phonon interaction and atomic disorder in the film. The transport properties of the FI' phase in the 30 nm film are masked because of the reduced interfacial coupling and smaller interface-to-volume ratio. This work demonstrates how thickness-dependent interfacial coupling leads to the formation of a theoretically predicted ferromagnetic-polaronic insulator, as illustrated in a new phase diagram, that is otherwise ferromagnetic metal (FM) in bulk form.
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Affiliation(s)
- Bangmin Zhang
- Department of Materials Science & Engineering, National University of Singapore , 117576, Singapore
| | - Lijun Wu
- Condensed Matter Physics & Materials Science Division, Brookhaven National Laboratory , Upton, New York 11973, United States
| | - Wei-Guo Yin
- Condensed Matter Physics & Materials Science Division, Brookhaven National Laboratory , Upton, New York 11973, United States
| | - Cheng-Jun Sun
- Advanced Photon Source, Argonne National Laboratory , Argonne, Illinois 60439, United States
| | - Ping Yang
- Singapore Synchrotron Light Source (SSLS), National University of Singapore , 5 Research Link, 117603 Singapore
| | - T Venkatesan
- NUSNNI-Nanocore, National University of Singapore , 117411, Singapore
- Department of Physics, National University of Singapore , 117542, Singapore
- Department of Electrical & Computer Engineering, National University of Singapore , 117576, Singapore
| | - Jingsheng Chen
- Department of Materials Science & Engineering, National University of Singapore , 117576, Singapore
| | - Yimei Zhu
- Condensed Matter Physics & Materials Science Division, Brookhaven National Laboratory , Upton, New York 11973, United States
| | - Gan Moog Chow
- Department of Materials Science & Engineering, National University of Singapore , 117576, Singapore
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Polar domain walls trigger magnetoelectric coupling. Sci Rep 2015; 5:13784. [PMID: 26387597 PMCID: PMC4585675 DOI: 10.1038/srep13784] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 08/05/2015] [Indexed: 11/09/2022] Open
Abstract
Interface physics in oxides heterostructures is pivotal in material’s science. Domain walls (DWs) in ferroic systems are examples of naturally occurring interfaces, where order parameter of neighboring domains is modified and emerging properties may develop. Here we show that electric tuning of ferroelastic domain walls in SrTiO3 leads to dramatic changes of the magnetic domain structure of a neighboring magnetic layer (La1/2Sr1/2MnO3) epitaxially clamped on a SrTiO3 substrate. We show that the properties of the magnetic layer are intimately connected to the existence of polar regions at twin boundaries of SrTiO3, developing at , that can be electrically modulated. These findings illustrate that by exploiting the responsiveness of DWs nanoregions to external stimuli, even in absence of any domain contribution, prominent and adjustable macroscopic reactions of neighboring layers can be obtained. We conclude that polar DWs, known to exist in other materials, can be used to trigger tunable responses and may lead to new ways for the manipulation of interfacial emerging properties.
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Vaz CAF, Walker FJ, Ahn CH, Ismail-Beigi S. Intrinsic interfacial phenomena in manganite heterostructures. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:123001. [PMID: 25721578 DOI: 10.1088/0953-8984/27/12/123001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We review recent advances in our understanding of interfacial phenomena that emerge when dissimilar materials are brought together at atomically sharp and coherent interfaces. In particular, we focus on phenomena that are intrinsic to the interface and review recent work carried out on perovskite manganites interfaces, a class of complex oxides whose rich electronic properties have proven to be a useful playground for the discovery and prediction of novel phenomena.
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Affiliation(s)
- C A F Vaz
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
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Aso R, Kan D, Shimakawa Y, Kurata H. Atomic level observation of octahedral distortions at the perovskite oxide heterointerface. Sci Rep 2014; 3:2214. [PMID: 23856752 PMCID: PMC3712312 DOI: 10.1038/srep02214] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 07/01/2013] [Indexed: 11/09/2022] Open
Abstract
For perovskite oxides, ABO3, slight octahedral distortions have close links to functional properties. While perovskite oxide heterostructures offer a good platform for controlling functionalities, atomistic understanding of octahedral distortion at the interface has been a challenge as it requires precise measurements of the oxygen atomic positions. Here we demonstrate an approach to clarify distortions at an atomic level using annular bright-field imaging in aberration-corrected scanning transmission electron microscopy, which provides precise mappings of cation and oxygen atomic positions from distortion-minimized images. This technique revealed significant distortions of RuO6 and ScO6 octahedra at the heterointerface between a SrRuO3 film and a GdScO3 substrate. We also found that structural mismatch was relieved within only four unit cells near the interface by shifting the oxygen atomic positions to accommodate octahedral tilt angle mismatch. The present results underscore the critical role of the oxygen atom in the octahedral connectivity at the perovskite oxide heterointerface.
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Affiliation(s)
- Ryotaro Aso
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, Japan
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Wohlhüter P, Rhensius J, Vaz CAF, Heidler J, Körner HS, Bisig A, Foerster M, Méchin L, Gaucher F, Locatelli A, Niño MA, El Moussaoui S, Nolting F, Goering E, Heyderman LJ, Kläui M. The effect of magnetic anisotropy on the spin configurations of patterned La(0.7)Sr(0.3)MnO3 elements. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2013; 25:176004. [PMID: 23567900 DOI: 10.1088/0953-8984/25/17/176004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We study the effect of magnetocrystalline anisotropy on the magnetic configurations of La0.7Sr0.3MnO3 bar and triangle elements using photoemission electron microscopy imaging. The dominant remanent state is a low energy flux-closure state for both thin (15 nm) and thick (50 nm) elements. The magnetocrystalline anisotropy, which competes with the dipolar energy, causes a strong modification of the spin configuration in the thin elements, depending on the shape, size and orientation of the structures. We investigate the magnetic switching processes and observe in triangular shaped elements a displacement of the vortex core along the easy axis for an external magnetic field applied close to the hard axis, which is well reproduced by micromagnetic simulations.
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Affiliation(s)
- P Wohlhüter
- Fachbereich Physik, Universität Konstanz, Universitätsstrasse 10, D-78457 Konstanz, Germany
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Islam MA, Rondinelli JM, Spanier JE. Normal mode determination of perovskite crystal structures with octahedral rotations: theory and applications. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2013; 25:175902. [PMID: 23567868 DOI: 10.1088/0953-8984/25/17/175902] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Nuclear site analysis methods are used to enumerate the normal modes of ABX3 perovskite polymorphs with octahedral rotations. We provide the modes of the 14 subgroups of the cubic aristotype describing the Glazer octahedral tilt patterns, which are obtained from rotations of the BX6 octahedra with different sense and amplitude about high-symmetry axes. We tabulate all normal modes of each tilt system and specify the contribution of each atomic species to the mode displacement pattern, elucidating the physical meaning of the symmetry unique modes. We have systematically generated 705 schematic atomic displacement patterns for the normal modes of all 15 (14 rotated + 1 unrotated) Glazer tilt systems. We show through some illustrative examples how to use these tables to identify the octahedral rotations, symmetric breathing, and first-order Jahn-Teller anti-symmetric breathing distortions of the BX6 octahedra, and the associated Raman selection rules. We anticipate that these tables and schematics will be useful in understanding the lattice dynamics of bulk perovskites and could serve as a reference point in elucidating the atomic origins of a wide range of physical properties of synthetic perovskite thin films and superlattices.
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Affiliation(s)
- Mohammad A Islam
- Department of Materials Science and Engineering, Drexel University, Philadelphia, PA 19104, USA
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Vaz CAF. Electric field control of magnetism in multiferroic heterostructures. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:333201. [PMID: 22824827 DOI: 10.1088/0953-8984/24/33/333201] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We review the recent developments in the electric field control of magnetism in multiferroic heterostructures, which consist of heterogeneous materials systems where a magnetoelectric coupling is engineered between magnetic and ferroelectric components. The magnetoelectric coupling in these composite systems is interfacial in origin, and can arise from elastic strain, charge, and exchange bias interactions, with different characteristic responses and functionalities. Moreover, charge transport phenomena in multiferroic heterostructures, where both magnetic and ferroelectric order parameters are used to control charge transport, suggest new possibilities to control the conduction paths of the electron spin, with potential for device applications.
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Affiliation(s)
- C A F Vaz
- SwissFEL, Paul Scherrer Institut, Villigen PSI, Switzerland.
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