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Baki A, Abdeldayem M, Morales C, Flege JI, Klimm D, Bierwagen O, Schwarzkopf J. Potential of La-Doped SrTiO 3 Thin Films Grown by Metal-Organic Vapor Phase Epitaxy for Thermoelectric Applications. CRYSTAL GROWTH & DESIGN 2023; 23:2522-2530. [PMID: 37065440 PMCID: PMC10101556 DOI: 10.1021/acs.cgd.2c01438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 02/27/2023] [Indexed: 06/19/2023]
Abstract
La-doped SrTiO3 thin films with high structural quality were homoepitaxially grown by the metal-organic vapor phase epitaxy (MOVPE) technique. Thermogravimetric characterization of the metal-organic precursors determines suitable flash evaporator temperatures for transferring the liquid source materials in the gas phase of the reactor chamber. An adjustment of the charge carrier concentration in the films, which is necessary for optimizing the thermoelectric power factor, was performed by introducing a defined amount of the metal-organic compound La(tmhd)3 and tetraglyme to the liquid precursor solution. X-ray diffraction and atomic force microscopy verified the occurrence of the pure perovskite phase exhibiting a high structural quality for all La concentrations. The electrical conductivity of the films obtained from Hall-effect measurements increases linearly with the La concentration in the gas phase, which is attributed to the incorporation of La3+ ions on the Sr2+ perovskite sites by substitution inferred from photoemission spectroscopy. The resulting structural defects were discussed concerning the formation of occasional Ruddlesden-Popper-like defects. The thermoelectric properties determined by Seebeck measurements demonstrate the high potential of SrTiO3 thin films grown by MOVPE for thermoelectric applications.
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Affiliation(s)
- Aykut Baki
- Leibniz-Institut
für Kristallzüchtung, Max-Born-Straße 2, 12489 Berlin, Germany
| | - Mohamed Abdeldayem
- Leibniz-Institut
für Kristallzüchtung, Max-Born-Straße 2, 12489 Berlin, Germany
| | - Carlos Morales
- Brandenburgische
Technische Universität Cottbus-Senftenberg, FG Angewandte Physik
und Halbleiterspektroskopie, Konrad-Zuse-Straße 1, 03046 Cottbus, Germany
| | - Jan Ingo Flege
- Brandenburgische
Technische Universität Cottbus-Senftenberg, FG Angewandte Physik
und Halbleiterspektroskopie, Konrad-Zuse-Straße 1, 03046 Cottbus, Germany
| | - Detlef Klimm
- Leibniz-Institut
für Kristallzüchtung, Max-Born-Straße 2, 12489 Berlin, Germany
| | - Oliver Bierwagen
- Paul-Drude-Institut
für Festkörperelektronik, Hausvogteiplatz 5-7, 10117 Berlin, Germany
| | - Jutta Schwarzkopf
- Leibniz-Institut
für Kristallzüchtung, Max-Born-Straße 2, 12489 Berlin, Germany
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Rusevich LL, Tyunina M, Kotomin EA, Nepomniashchaia N, Dejneka A. The electronic properties of SrTiO 3-δ with oxygen vacancies or substitutions. Sci Rep 2021; 11:23341. [PMID: 34857848 PMCID: PMC8639995 DOI: 10.1038/s41598-021-02751-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 11/17/2021] [Indexed: 12/14/2022] Open
Abstract
The electronic properties, including bandgap and conductivity, are critical for nearly all applications of multifunctional perovskite oxide ferroelectrics. Here we analysed possibility to induce semiconductor behaviour in these materials, which are basically insulators, by replacement of several percent of oxygen atoms with nitrogen, hydrogen, or vacancies. We explored this approach for one of the best studied members of the large family of ABO3 perovskite ferroelectrics - strontium titanate (SrTiO3). The atomic and electronic structure of defects were theoretically investigated using the large-scale first-principles calculations for both bulk crystal and thin films. The results of calculations were experimentally verified by studies of the optical properties at photon energies from 25 meV to 8.8 eV for in-situ prepared thin films. It was demonstrated that substitutions and vacancies prefer locations at surfaces or phase boundaries over those inside crystallites. At the same time, local states in the bandgap can be produced by vacancies located both inside the crystals and at the surface, but by nitrogen substitution only inside crystals. Wide-bandgap insulator phases were evidenced for all defects. Compared to pure SrTiO3 films, bandgap widening due to defects was theoretically predicted and experimentally detected.
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Affiliation(s)
- L L Rusevich
- Institute of Solid State Physics, University of Latvia, Kengaraga Str. 8, Riga, 1063, Latvia.
| | - M Tyunina
- Microelectronics Research Unit, Faculty of Information Technology and Electrical Engineering, University of Oulu, P. O. Box 4500, 90014, Oulu, Finland.
- Institute of Physics of the Czech Academy of Sciences, Na Slovance 2, 18221, Prague, Czech Republic.
| | - E A Kotomin
- Institute of Solid State Physics, University of Latvia, Kengaraga Str. 8, Riga, 1063, Latvia
- Max Planck Institute for Solid State Research, Heisenberg Str. 1, 70569, Stuttgart, Germany
| | - N Nepomniashchaia
- Institute of Physics of the Czech Academy of Sciences, Na Slovance 2, 18221, Prague, Czech Republic
| | - A Dejneka
- Institute of Physics of the Czech Academy of Sciences, Na Slovance 2, 18221, Prague, Czech Republic
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Turchenko VA, Trukhanov SV, Kostishin VG, Damay F, Porcher F, Klygach DS, Vakhitov MG, Lyakhov D, Michels D, Bozzo B, Fina I, Almessiere MA, Slimani Y, Baykal A, Zhou D, Trukhanov AV. Features of structure, magnetic state and electrodynamic performance of SrFe 12-xIn xO 19. Sci Rep 2021; 11:18342. [PMID: 34526572 PMCID: PMC8443609 DOI: 10.1038/s41598-021-97684-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 08/27/2021] [Indexed: 11/15/2022] Open
Abstract
Indium-substituted strontium hexaferrites were prepared by the conventional solid-phase reaction method. Neutron diffraction patterns were obtained at room temperature and analyzed using the Rietveld methods. A linear dependence of the unit cell parameters is found. In3+ cations are located mainly in octahedral positions of 4fVI and 12 k. The average crystallite size varies within 0.84–0.65 μm. With increasing substitution, the TC Curie temperature decreases monotonically down to ~ 520 K. ZFC and FC measurements showed a frustrated state. Upon substitution, the average and maximum sizes of ferrimagnetic clusters change in the opposite direction. The Mr remanent magnetization decreases down to ~ 20.2 emu/g at room temperature. The Ms spontaneous magnetization and the keff effective magnetocrystalline anisotropy constant are determined. With increasing substitution, the maximum of the ε/ real part of permittivity decreases in magnitude from ~ 3.3 to ~ 1.9 and shifts towards low frequencies from ~ 45.5 GHz to ~ 37.4 GHz. The maximum of the tg(α) dielectric loss tangent decreases from ~ 1.0 to ~ 0.7 and shifts towards low frequencies from ~ 40.6 GHz to ~ 37.3 GHz. The low-frequency maximum of the μ/ real part of permeability decreases from ~ 1.8 to ~ 0.9 and slightly shifts towards high frequencies up to ~ 34.7 GHz. The maximum of the tg(δ) magnetic loss tangent decreases from ~ 0.7 to ~ 0.5 and shifts slightly towards low frequencies from ~ 40.5 GHz to ~ 37.7 GHz. The discussion of microwave properties is based on the saturation magnetization, natural ferromagnetic resonance and dielectric polarization types.
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Affiliation(s)
- V A Turchenko
- Joint Institute for Nuclear Research, 6 Joliot-Curie Str., 141980, Dubna, Russia.,South Ural State University, 76, Lenin Av., 454080, Chelyabinsk, Russia.,Donetsk Institute of Physics and Technology Named After O.O. Galkin of the NASU, 46 Nauki Av., Kiev, 03680, Ukraine
| | - S V Trukhanov
- South Ural State University, 76, Lenin Av., 454080, Chelyabinsk, Russia. .,SSPA "Scientific and Practical Materials Research Centre of NAS of Belarus", 19 P. Brovki str., 220072, Minsk, Belarus. .,National University of Science and Technology "MISiS", Leninsky av., 4, Moscow, Russia, 119049.
| | - V G Kostishin
- National University of Science and Technology "MISiS", Leninsky av., 4, Moscow, Russia, 119049
| | - F Damay
- Laboratoire Leon Brillouin, UMR12 CEA-CNRS, Bât. 563 CEA Saclay, 91191, Gif sur Yvette Cedex, France
| | - F Porcher
- Laboratoire Leon Brillouin, UMR12 CEA-CNRS, Bât. 563 CEA Saclay, 91191, Gif sur Yvette Cedex, France
| | - D S Klygach
- South Ural State University, 76, Lenin Av., 454080, Chelyabinsk, Russia.,Ural Federal University named after the First President of Russia B.N. Yeltsin, Yekaterinburg, Russia, 620002
| | - M G Vakhitov
- South Ural State University, 76, Lenin Av., 454080, Chelyabinsk, Russia.,Ural Federal University named after the First President of Russia B.N. Yeltsin, Yekaterinburg, Russia, 620002
| | - D Lyakhov
- Computer, Electrical and Mathematical Science and Engineering Division, 4700 King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia
| | - D Michels
- Computer, Electrical and Mathematical Science and Engineering Division, 4700 King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia
| | - B Bozzo
- Institut de Ciencia de Materials de Barcelona-CSIC, Campus de la UAB, 08193, Bellaterra, Barcelona, Spain
| | - I Fina
- Institut de Ciencia de Materials de Barcelona-CSIC, Campus de la UAB, 08193, Bellaterra, Barcelona, Spain
| | - M A Almessiere
- Department of Biophysics, Institute for Research and Medical Consultations (IRMC), Imam Abdulrahman Bin Faisal University, P.O. Box 1982, Dammam, 31441, Saudi Arabia.,Department of Physics, College of Science, Imam Abdulrahman Bin Faisal University, P.O. Box 1982, Dammam, 31441, Saudi Arabia
| | - Y Slimani
- Department of Biophysics, Institute for Research and Medical Consultations (IRMC), Imam Abdulrahman Bin Faisal University, P.O. Box 1982, Dammam, 31441, Saudi Arabia
| | - A Baykal
- Department of Nanomedicine Research, Institute for Research and Medical Consultations (IRMC), Imam Abdulrahman Bin Faisal University, P.O. Box 1982, Dammam, 31441, Saudi Arabia
| | - D Zhou
- Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, School of Electronic Science and Engineering, Xi'an Jiaotong University, Xi'an, 710049, China
| | - A V Trukhanov
- South Ural State University, 76, Lenin Av., 454080, Chelyabinsk, Russia.,SSPA "Scientific and Practical Materials Research Centre of NAS of Belarus", 19 P. Brovki str., 220072, Minsk, Belarus.,National University of Science and Technology "MISiS", Leninsky av., 4, Moscow, Russia, 119049
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