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Pajerowski DM, Krayer LJ, Kirby BJ, Maranville BB, Borchers JA, Kim KW, Norton DP. Pulsed laser deposition films from a Ba 2FeMoO 6 target onto SrTiO 3[001]: Chemical and magnetic inhomogeneity. JOURNAL OF APPLIED PHYSICS 2018; 124:10.1063/1.5039401. [PMID: 38915878 PMCID: PMC11194730 DOI: 10.1063/1.5039401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/26/2024]
Abstract
Pulsed laser deposition films from Ba2FeMoO6 (BFMO) targets onto SrTiO3[001] (STO) substrates have been reported previously to have non-zero magnetism at 300 K, a majority of magnetic ordering at 240 K that is less than the 370 K ordering temperature of polycrystalline BFMO, and suppressed saturation magnetization compared to polycrystalline BFMO. To interrogate these previously reported observations of BFMO on STO, we have used a combination of x-ray diffraction, atomic force microscopy, x-ray and neutron reflectivity, and x-ray photoelectron spectroscopy that shows inhomogeneities. The present results show off-stoichiometry on the A-site by incorporation of Sr from the substrate and on the B-site to have %Fe/%Mo > 1 by evolution of BaMoO4. There is an enhanced ordering temperature and magnetic response nearer to the SrTiO3 interface compared to the air interface. Depth dependent strain and microstructure are needed to explain the magnetic response. Holistic considerations and implications are also discussed.
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Affiliation(s)
- Daniel M Pajerowski
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-6102, USA
| | - Lisa J Krayer
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-6102, USA
| | - Brian J Kirby
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-6102, USA
| | - Brian B Maranville
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-6102, USA
| | - Julie A Borchers
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-6102, USA
| | - Kyeong-Won Kim
- Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611, USA
| | - David P Norton
- Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611, USA
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Saloaro M, Hoffmann M, Adeagbo WA, Granroth S, Deniz H, Palonen H, Huhtinen H, Majumdar S, Laukkanen P, Hergert W, Ernst A, Paturi P. Toward Versatile Sr2FeMoO6-Based Spintronics by Exploiting Nanoscale Defects. ACS APPLIED MATERIALS & INTERFACES 2016; 8:20440-20447. [PMID: 27447197 DOI: 10.1021/acsami.6b04132] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
To actualize the high spintronic application potential of complex magnetic oxides, it is essential to fabricate these materials as thin films with the best possible magnetic and electrical properties. Sr2FeMoO6 is an outstanding candidate for such applications, but presently no thin film synthesis route, which would preserve the magnetic properties of bulk Sr2FeMoO6, is currently known. In order to address this problem, we present a comprehensive experimental and theoretical study where we link the magnetic and half metallic properties of Sr2FeMoO6 thin films to lattice strain, Fe-Mo antisite disorder and oxygen vacancies. We find the intrinsic effect of strain on the magnetic properties to be very small, but also that an increased strain will significantly stabilize the Sr2FeMoO6 lattice against the formation of antisite disorder and oxygen vacancies. These defects, on the other hand, are recognized to drastically influence the magnetism of Sr2FeMoO6 in a nonlinear manner. On the basis of the findings, we propose strain manipulation and reductive annealing as optimization pathways for improving the spintronic functionality of Sr2FeMoO6.
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Affiliation(s)
- Minnamari Saloaro
- Wihuri Physical Laboratory, Department of Physics and Astronomy, University of Turku , Turku FI-20014, Finland
| | - Martin Hoffmann
- IFW Dresden , P.O. Box 27 01 16, D-01171 Dresden, Germany
- Institut für Physik, Martin Luther University Halle-Wittenberg , Von-Seckendorff-Platz 1, 06120 Halle, Germany
- Max Planck Institute of Microstructure Physics , Weinberg 2, 06120 Halle, Germany
| | - Waheed A Adeagbo
- Institut für Physik, Martin Luther University Halle-Wittenberg , Von-Seckendorff-Platz 1, 06120 Halle, Germany
| | - Sari Granroth
- Materials Research Laboratory, Department of Physics and Astronomy, University of Turku , Turku FI-20014, Finland
| | - Hakan Deniz
- Max Planck Institute of Microstructure Physics , Weinberg 2, 06120 Halle, Germany
| | - Heikki Palonen
- Wihuri Physical Laboratory, Department of Physics and Astronomy, University of Turku , Turku FI-20014, Finland
| | - Hannu Huhtinen
- Wihuri Physical Laboratory, Department of Physics and Astronomy, University of Turku , Turku FI-20014, Finland
| | - Sayani Majumdar
- Wihuri Physical Laboratory, Department of Physics and Astronomy, University of Turku , Turku FI-20014, Finland
- NanoSpin, Department of Applied Physics, Aalto University School of Science , P.O. Box 15100, FI-00076 Aalto, Finland
| | - Pekka Laukkanen
- Materials Research Laboratory, Department of Physics and Astronomy, University of Turku , Turku FI-20014, Finland
| | - Wolfram Hergert
- Institut für Physik, Martin Luther University Halle-Wittenberg , Von-Seckendorff-Platz 1, 06120 Halle, Germany
| | - Arthur Ernst
- Max Planck Institute of Microstructure Physics , Weinberg 2, 06120 Halle, Germany
| | - Petriina Paturi
- Wihuri Physical Laboratory, Department of Physics and Astronomy, University of Turku , Turku FI-20014, Finland
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Saloaro M, Deniz H, Huhtinen H, Palonen H, Majumdar S, Paturi P. The predominance of substrate induced defects in magnetic properties of Sr2FeMoO6 thin films. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:386001. [PMID: 26338059 DOI: 10.1088/0953-8984/27/38/386001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
A systematic study of epitaxially grown Sr2FeMoO6 thin films on SrTiO3, (LaAlO3)0.3(Sr2AlTaO6)0.7, SrLaAlO4 and MgO single crystal substrates were made. Transmission electron microscopy investigations showed sharp substrate/films interfaces and increased defect concentration with increased lattice mismatch, indicating defect formation such as dislocations, low angle grain boundaries and stacking faults as a strain relaxation mechanism. Large enough compressive mismatch cause the over-relaxation of the lattice parameters through reorganization or interface defects, which was observed as a tensile strain in films with compressive mismatch larger than -1.05%. All the films with compressive mismatch were phase pure and epitaxially textured while signatures of SrMoO4 parasitic particle was found only in the film grown on MgO. No correlation between the antisite disorder and other structural defects or magnetic properties were found. Instead, the saturation magnetization, Curie temperature, magnetic domain rotation etc are higly dependent on the lattice mismatch induced defects, which outshines the possible correlation with B-site ordering.
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Affiliation(s)
- M Saloaro
- Wihuri Physical Laboratory, Department of Physics and Astronomy, FI-20014 University of Turku, Finland
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Saloaro M, Majumdar S, Huhtinen H, Paturi P. Absence of traditional magnetoresistivity mechanisms in Sr2FeMoO6 thin films grown on SrTiO3, MgO and NdGaO3 substrates. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:366003. [PMID: 22893014 DOI: 10.1088/0953-8984/24/36/366003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Magnetoresistive double perovskite Sr(2)FeMoO(6) thin films were grown with two different deposition pressures on SrTiO(3), MgO and NdGaO(3) substrates by pulsed laser deposition and thorough structural, magnetic and magneto-transport characterization was made. According to x-ray diffraction, all the films were phase pure and fully textured. Indication of substrate dependent strain and low angle grain boundaries was found, especially in films on MgO. Both the deposition pressure and the choice of the substrate have a strong influence on the saturation magnetization, M(s), and Curie temperature, T(C). The structural and magnetic data indicate the presence of anti-site disorder (ASD) in the films. The temperature dependence of resistivity showed semiconductive behaviour at temperatures below 100 K and metallic behaviour at higher temperatures. The semiconductive behaviour was found to increase with increasing ASD. In good quality films, up to 12% negative magnetoresistance (MR) was observed and films grown on MgO and NGO substrates also showed low field MR. However, the most significant observation of this study was that the magnetoresistivity of these Sr(2)FeMoO(6) thin films could not be explained with any traditional MR mechanism, but carried the clear signature of superposition of different mechanisms, in particular low angle grain boundary tunnelling and suppression of antiferromagnetically ordered domains under a magnetic field.
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Affiliation(s)
- M Saloaro
- Wihuri Physical Laboratory, Department of Physics and Astronomy, University of Turku, FI-20014 University of Turku, Finland.
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