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Eremeev K, Loiko P, Zhao C, Lin ZL, Mateos X, Zin Elabedine G, Camy P, Braud A, Griebner U, Petrov V, Zhang G, Li S, Hang Y, Chen W. Growth, spectroscopy and laser operation of Tm,Ho:GdScO 3 perovskite crystal. OPTICS EXPRESS 2024; 32:13527-13542. [PMID: 38859320 DOI: 10.1364/oe.518709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Accepted: 03/15/2024] [Indexed: 06/12/2024]
Abstract
We report on the growth, polarized spectroscopy and first laser operation of an orthorhombic (space group Pnma) Tm3+,Ho3+-codoped gadolinium orthoscandate (GdScO3) perovskite-type crystal. A single crystal of 3.76 at.% Tm, 0.35 at.% Ho:GdScO3 was grown by the Czochralski method. Its polarized absorption and fluorescence properties were studied revealing a broadband emission around 2 µm. The parameters of the Tm3+ ↔ Ho3+ energy transfer was quantified, P28 = 1.30 × 10-22 cm3µs-1, and P71 = 0.99 × 10-23 cm3µs-1, and the thermal equilibrium lifetime was measured to be 3.5 ms. The crystal-field splitting of Tm3+ and Ho3+ multiplets in Cs symmetry sites of the perovskite structure was determined by low-temperature spectroscopy and the mechanism of spectral line broadening is discussed. The continuous-wave Tm,Ho:GdScO3 laser generated 1.16 W at ∼2.1 µm with a slope efficiency of 50.5%, a laser threshold of 184 mW, a linear laser polarization (E || c) and a spatially single-mode output. The Tm,Ho:GdScO3 crystal is promising for broadly tunable and femtosecond mode-locked lasers emitting above 2 µm.
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Guo J, Li S, Zhao C, Hang Y, Zeng HJ, Lin ZL, Zhang G, Elabedine GZ, Mateos X, Loiko P, Petrov V, Chen W, Liang X. SESAM mode-locked Yb:GdScO 3 laser. OPTICS EXPRESS 2024; 32:7865-7872. [PMID: 38439456 DOI: 10.1364/oe.512293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Accepted: 01/31/2024] [Indexed: 03/06/2024]
Abstract
We report on the investigation of continuous-wave (CW) and SEmiconductor Saturable Absorber Mirror (SESAM) mode-locked operation of a Yb:GdScO3 laser. Using a single-transverse-mode, fiber-coupled InGaAs laser diode at 976 nm as a pump source, the Yb:GdScO3 laser delivers 343 mW output power at 1062 nm in the CW regime, which corresponds to a slope efficiency of 52%. Continuous tuning is possible across a wavelength range of 84 nm (1027-1111 nm). Using a commercial SESAM to initiate mode-locking and stabilize soliton-type pulse shaping, the Yb:GdScO3 laser produces pulses as short as 42 fs at 1065.9 nm, with an average output power of 40 mW at 66.89 MHz. To the best of our knowledge, this is the first demonstration of passively mode-locking with Yb:GdScO3 crystal.
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Yi W, Kawasaki T, Zhang Y, Akamatsu H, Ota R, Torii S, Fujita K. La 2SrSc 2O 7: A-Site Cation Disorder Induces Ferroelectricity in Ruddlesden-Popper Layered Perovskite Oxide. J Am Chem Soc 2024; 146:4570-4581. [PMID: 38320273 DOI: 10.1021/jacs.3c11546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2024]
Abstract
Rational design of ferroelectrics in layered perovskites, like n = 2 Ruddlesden-Popper (RP) phase A3B2O7, has been achieved by the hybrid-improper ferroelectric (HIF) mechanism, in which an electric polarization is induced via a trilinear coupling to nonpolar BO6 octahedral rotation and tilt distortions around crystallographic axes. In the present work, hybrid improper ferroelectricity in n = 2 RP-type La2SrSc2O7 induced by the disordering of Sr2+/La3+ cations on the A-sites in rocksalt ([Sr/La]Rs = 25/75) and perovskite ([Sr/La]Pv = 50/50) layers is demonstrated through experimental and theoretical investigations. The ferroelectric A21am structure (a-a-c+ in Glazer notation) at room temperature and the second-order phase transition to paraelectric Amam structure (a-a-c0) at TC ∼ 600 K are determined by a combination of X-ray and neutron diffraction and optical second harmonic generation. The ferroelectric hysteresis loop measurements prove the switchable electric polarization indicative of ferroelectricity. These results represent an unprecedented example of ferroelectricity in the n = 2 RP family of Ln2AB2O7 with inequivalent Ln3+ and A2+ cations. Combining the abovementioned experimental results with the first-principles calculations, we verify the role of Sr/La distributions in regulating the interlayer rumpling, which, in addition to the structural tolerance factor, is key to controlling the structural distortions of RP phases. The stabilization of the ferroelectric, a-a-c+ distorted structure is a consequence of the disordered Sr/La distribution on the A-sites, which suppresses the rumpling-induced octahedral deformations in competition with the octahedral rotations and thus enables the concurrence of a0a0c+ rotations and a-a-c0 tilts required for the HIF mechanism. This work demonstrates the possibility of altering the crystal symmetry of RP phases through the A-site cation disorder and provides a complementary approach to the rational design of new HIF materials.
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Affiliation(s)
- Wei Yi
- Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Katsura Nishikyo-ku, Kyoto 615-8510, Japan
| | - Tatsushi Kawasaki
- Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Katsura Nishikyo-ku, Kyoto 615-8510, Japan
| | - Yang Zhang
- Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Katsura Nishikyo-ku, Kyoto 615-8510, Japan
| | - Hirofumi Akamatsu
- Department of Applied Chemistry, School of Engineering, Kyushu University, Motooka, Fukuoka 812-0053, Japan
| | - Ryo Ota
- HVEM Laboratory at Center for Advanced Research of Energy and Materials, Graduate School of Engineering, Hokkaido University, Sapporo 060-8628, Japan
| | - Shuki Torii
- Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Ibaraki 319-1106, Japan
| | - Koji Fujita
- Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Katsura Nishikyo-ku, Kyoto 615-8510, Japan
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Liu F, Golani P, Truttmann TK, Evangelista I, Smeaton MA, Bugallo D, Wen J, Manjeshwar AK, May SJ, Kourkoutis LF, Janotti A, Koester SJ, Jalan B. Doping the Undopable: Hybrid Molecular Beam Epitaxy Growth, n-Type Doping, and Field-Effect Transistor Using CaSnO 3. ACS NANO 2023; 17:16912-16922. [PMID: 37638732 DOI: 10.1021/acsnano.3c04003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/29/2023]
Abstract
The alkaline earth stannates are touted for their wide band gaps and the highest room-temperature electron mobilities among all of the perovskite oxides. CaSnO3 has the highest measured band gap in this family and is thus a particularly promising ultrawide band gap semiconductor. However, discouraging results from previous theoretical studies and failed doping attempts had described this material as "undopable". Here we redeem CaSnO3 using hybrid molecular beam epitaxy, which provides an adsorption-controlled growth for the phase-pure, epitaxial, and stoichiometric CaSnO3 films. By introducing lanthanum (La) as an n-type dopant, we demonstrate the robust and predictable doping of CaSnO3 with free electron concentrations, n3D, from 3.3 × 1019 cm-3 to 1.6 × 1020 cm-3. The films exhibit a maximum room-temperature mobility of 42 cm2 V-1 s-1 at n3D = 3.3 × 1019 cm-3. Despite having a comparable radius as the host ion, La expands the lattice parameter. Using density functional calculations, this effect is attributed to the energy gain by lowering the conduction band upon volume expansion. Finally, we exploit robust doping by fabricating CaSnO3-based field-effect transistors. The transistors show promise for CaSnO3's high-voltage capabilities by exhibiting low off-state leakage below 2 × 10-5 mA/mm at a drain-source voltage of 100 V and on-off ratios exceeding 106. This work serves as a starting point for future studies on the semiconducting properties of CaSnO3 and many devices that could benefit from CaSnO3's exceptionally wide band gap.
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Affiliation(s)
- Fengdeng Liu
- Department of Chemical Engineering and Materials Science, University of Minnesota-Twin Cities, Minneapolis, Minnesota 55455, United States
| | - Prafful Golani
- Department of Electrical and Computer Engineering, University of Minnesota-Twin Cities, Minneapolis, Minnesota 55455, United States
| | - Tristan K Truttmann
- Department of Chemical Engineering and Materials Science, University of Minnesota-Twin Cities, Minneapolis, Minnesota 55455, United States
| | - Igor Evangelista
- Department of Materials Science and Engineering, University of Delaware, Newark, Delaware 19716, United States
| | - Michelle A Smeaton
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States
| | - David Bugallo
- Department of Materials Science and Engineering, Drexel University, Philadelphia, Pennsylvania 19104, United States
- Centro de Investigación en Química Biolóxica e Materiais Moleculares (CIQUS), Universidade de Santiago de Compostela, Santiago de Compostela, 15782, Spain
| | - Jiaxuan Wen
- Department of Electrical and Computer Engineering, University of Minnesota-Twin Cities, Minneapolis, Minnesota 55455, United States
| | - Anusha Kamath Manjeshwar
- Department of Chemical Engineering and Materials Science, University of Minnesota-Twin Cities, Minneapolis, Minnesota 55455, United States
| | - Steven J May
- Department of Materials Science and Engineering, Drexel University, Philadelphia, Pennsylvania 19104, United States
| | - Lena F Kourkoutis
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, United States
- Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, New York 14853, United States
| | - Anderson Janotti
- Department of Materials Science and Engineering, University of Delaware, Newark, Delaware 19716, United States
| | - Steven J Koester
- Department of Electrical and Computer Engineering, University of Minnesota-Twin Cities, Minneapolis, Minnesota 55455, United States
| | - Bharat Jalan
- Department of Chemical Engineering and Materials Science, University of Minnesota-Twin Cities, Minneapolis, Minnesota 55455, United States
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5
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Hou W, Xue Y, Qin Z, Tang H, Xie G, Wang Q, Xu X, Xu J. Efficient continuous wave and passively Q switched Er:GdScO 3 laser using Fe:ZnSe at 2.8 µm. OPTICS LETTERS 2023; 48:2118-2121. [PMID: 37058656 DOI: 10.1364/ol.487752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 03/09/2023] [Indexed: 06/19/2023]
Abstract
We report on diode-pumped continuous wave and passively Q switched Er:GdScO3 crystal lasers at around 2.8 µm. A continuous wave output power of 579 mW was obtained with a slope efficiency of 16.6%. Using Fe:ZnSe as a saturable absorber, a passively Q switched laser operation was realized. A maximum output power of 32 mW was generated with the shortest pulse duration of 286 ns at a repetition rate of 157.3 kHz, leading to a pulse energy of 204 nJ and a pulse peak power of 0.7 W.
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6
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Greenstein EP, Poeppelmeier KR, Marks LD. Wet to Dry Controls Lanthanide Scandate Synthesis. Inorg Chem 2023; 62:4853-4860. [PMID: 36921211 DOI: 10.1021/acs.inorgchem.2c04107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/17/2023]
Abstract
The choice of temperature and gas conditions used in a water pressure-controlled reactor is guided by density functional theory (DFT) to synthesize nearly phase-pure lanthanide scandate nanoparticles (LnScO3, Ln = La, Nd, Sm, Gd). In this synthetic method, low water-vapor partial pressures, well below water's gas liquidus, inhibit particle growth, while an excess of water vapor results in undesired rare-earth hydroxide and oxyhydroxide secondary phases. The optimal humidity for high-purity LnScO3 particle synthesis is shown to vary with the lanthanide; DFT is used to calculate the thermodynamics of secondary phase formation for each lanthanide tested such that the role of water vapor may be quantified and used to maintain phase purity (greater than 96 mol %) across the series. The combination of thermodynamic calculation and experimental confirmation with this pressure-controlled reactor provides an opportunity to explore analogous syntheses of other inorganic perovskite nanoparticles.
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Affiliation(s)
- Emily P Greenstein
- Department of Materials Science & Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Kenneth R Poeppelmeier
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Laurence D Marks
- Department of Materials Science & Engineering, Northwestern University, Evanston, Illinois 60208, United States
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Chen S, Zhang Q, Li X, Zhao J, Lin S, Jin Q, Hong H, Huon A, Charlton T, Li Q, Yan W, Wang J, Ge C, Wang C, Wang B, Fitzsimmons MR, Guo H, Gu L, Yin W, Jin KJ, Guo EJ. Atomically engineered cobaltite layers for robust ferromagnetism. SCIENCE ADVANCES 2022; 8:eabq3981. [PMID: 36306366 PMCID: PMC9616489 DOI: 10.1126/sciadv.abq3981] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Emergent phenomena at heterointerfaces are directly associated with the bonding geometry of adjacent layers. Effective control of accessible parameters, such as the bond length and bonding angles, offers an elegant method to tailor competing energies of the electronic and magnetic ground states. In this study, we construct unit-thick syntactic layers of cobaltites within a strongly tilted octahedral matrix via atomically precise synthesis. The octahedral tilt patterns of adjacent layers propagate into cobaltites, leading to a continuation of octahedral tilting while maintaining substantial misfit tensile strain. These effects induce severe rumpling within an atomic plane of neighboring layers, further triggering the electronic reconstruction between the splitting orbitals. First-principles calculations reveal that the cobalt ions transit to a higher spin state level upon octahedral tilting, resulting in robust ferromagnetism in ultrathin cobaltites. This work demonstrates a design methodology for fine-tuning the lattice and spin degrees of freedom in correlated quantum heterostructures by exploiting epitaxial geometric engineering.
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Affiliation(s)
- Shengru Chen
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qinghua Zhang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Xujing Li
- University of Chinese Academy of Sciences, Beijing 100049, China
- Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
- Spallation Neutron Source Science Center, Dongguan 523803, China
| | - Jiali Zhao
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Shan Lin
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qiao Jin
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Haitao Hong
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Amanda Huon
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- Department of Mathematics, Physics, and Statistics, University of the Sciences, Philadelphia, PA 19104, USA
| | - Timothy Charlton
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Qian Li
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, China
| | - Wensheng Yan
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, China
| | - Jiaou Wang
- Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
| | - Chen Ge
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Can Wang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Baotian Wang
- Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
- Spallation Neutron Source Science Center, Dongguan 523803, China
| | - Michael R. Fitzsimmons
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996, USA
| | - Haizhong Guo
- Key Laboratory of Material Physics, Ministry of Education, School of Physics and Microelectronics, Zhengzhou University, Zhengzhou 450001, China
| | - Lin Gu
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Wen Yin
- Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
- Spallation Neutron Source Science Center, Dongguan 523803, China
- Corresponding author. (W.Y.); (K.-j.J.); (E.J.G.)
| | - Kui-juan Jin
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
- Corresponding author. (W.Y.); (K.-j.J.); (E.J.G.)
| | - Er Jia Guo
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
- Corresponding author. (W.Y.); (K.-j.J.); (E.J.G.)
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Electric-field control of the nucleation and motion of isolated three-fold polar vertices. Nat Commun 2022; 13:6340. [PMID: 36284138 PMCID: PMC9596422 DOI: 10.1038/s41467-022-33973-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 10/10/2022] [Indexed: 11/21/2022] Open
Abstract
Recently various topological polar structures have been discovered in oxide thin films. Despite the increasing evidence of their switchability under electrical and/or mechanical fields, the dynamic property of isolated ones, which is usually required for applications such as data storage, is still absent. Here, we show the controlled nucleation and motion of isolated three-fold vertices under an applied electric field. At the PbTiO3/SrRuO3 interface, a two-unit-cell thick SrTiO3 layer provides electrical boundary conditions for the formation of three-fold vertices. Utilizing the SrTiO3 layer and in situ electrical testing system, we find that isolated three-fold vertices can move in a controllable and reversible manner with a velocity up to ~629 nm s−1. Microstructural evolution of the nucleation and propagation of isolated three-fold vertices is further revealed by phase-field simulations. This work demonstrates the ability to electrically manipulate isolated three-fold vertices, shedding light on the dynamic property of isolated topological polar structures. Despite various known topological polar structures, the dynamic property of isolated ones is still poorly understood. Here, the authors show the controlled nucleation and ability to move of isolated three-fold vertices under an applied electric field.
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9
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Mechanism of Surface Defects in Ultra-Precision Machining of Sesquioxide Laser Crystal Tm: GdScO3. MICROMACHINES 2022; 13:mi13081250. [PMID: 36014172 PMCID: PMC9412520 DOI: 10.3390/mi13081250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 08/01/2022] [Accepted: 08/01/2022] [Indexed: 02/01/2023]
Abstract
It is well-known that the surface quality of laser gain crystal elements is very high in order to ensure the stability of laser system and laser output quality. In the ultra-precision machining process of a new sesquioxide laser crystal Tm: GdScO3, it is required to achieve very high surface shape and very low surface defects. In this paper, the molecular dynamics simulation model of single particle grinding was established. It was found that the normal load and tangential friction imposed by abrasive particles on the surface of components cause the spalling of atoms on the substrate surface, which constitutes the removal of materials at the macro-level. At the same time, it causes the displacement of the sub surface atoms, which constitutes the microscopic defects in the structure. Through the structural characterization of macro defects, it was confirmed that the essence of micro defects is the amorphous and distortion of surface structure, and the depth can reach 100 nm. The results of lapping and polishing experiments show that the adjustment of pressure has a limited effect on the improvement of surface defects in the process of machining crystal elements with granular abrasive.
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Crystal structure and octahedral deformation of orthorhombic perovskite ABO3: Case study of SrRuO3. J SOLID STATE CHEM 2022. [DOI: 10.1016/j.jssc.2022.122998] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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11
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Achievements and Future Perspectives of the Trivalent Thulium-Ion-Doped Mixed-Sesquioxide Ceramics for Laser Applications. MATERIALS 2022; 15:ma15062084. [PMID: 35329536 PMCID: PMC8950303 DOI: 10.3390/ma15062084] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 03/05/2022] [Accepted: 03/07/2022] [Indexed: 02/04/2023]
Abstract
This paper is devoted to reviewing the latest results achieved in solid-state lasers based on thulium-doped mixed-sesquioxide ceramics, i.e., (Lu,Sc,Y)2O3. The near- and mid-infrared regions are of interest for many applications, from medicine to remote sensing, as they match molecular fingerprints and cover several atmospheric transparency windows. These matrices are characterized by a strong electron–phonon interaction—which results in a large splitting of the ground state—and by a spectral broadening of the optical transition suitable for developing tunable and short-pulse lasers. In particular, the manuscript reports on the trivalent thulium laser transitions at 1.5, 1.9, and 2.3 µm, along with the thermal and optical characteristics of the (Lu,Sc,Y)2O3 ceramics, including the fabrication techniques, spectroscopic and optical properties, and laser performances achieved in different pumping regimes, such as continuous-wave (CW), quasi-CW, and pulsed modes. A comparison of the performance obtained with these mixed-sesquioxide ceramics and with the corresponding crystals is reported.
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Abstract
Ferroics, especially ferromagnets, can form complex topological spin structures such as vortices1 and skyrmions2,3 when subjected to particular electrical and mechanical boundary conditions. Simple vortex-like, electric-dipole-based topological structures have been observed in dedicated ferroelectric systems, especially ferroelectric-insulator superlattices such as PbTiO3/SrTiO3, which was later shown to be a model system owing to its high depolarizing field4-8. To date, the electric dipole equivalent of ordered magnetic spin lattices driven by the Dzyaloshinskii-Moriya interaction (DMi)9,10 has not been experimentally observed. Here we examine a domain structure in a single PbTiO3 epitaxial layer sandwiched between SrRuO3 electrodes. We observe periodic clockwise and anticlockwise ferroelectric vortices that are modulated by a second ordering along their toroidal core. The resulting topology, supported by calculations, is a labyrinth-like pattern with two orthogonal periodic modulations that form an incommensurate polar crystal that provides a ferroelectric analogue to the recently discovered incommensurate spin crystals in ferromagnetic materials11-13. These findings further blur the border between emergent ferromagnetic and ferroelectric topologies, clearing the way for experimental realization of further electric counterparts of magnetic DMi-driven phases.
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13
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Altering magnetic and optical features of rare earth orthoferrite LuFeO3 ceramics via substitution of Ir into Fe sites. J SOLID STATE CHEM 2022. [DOI: 10.1016/j.jssc.2021.122701] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Zhang Y, Li S, Du X, Guo J, Gong Q, Tao S, Zhang P, Fang Q, Pan S, Zhao C, Liang X, Hang Y. Yb:GdScO 3 crystal for efficient ultrashort pulse lasers. OPTICS LETTERS 2021; 46:3641-3644. [PMID: 34329246 DOI: 10.1364/ol.431243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Accepted: 06/18/2021] [Indexed: 06/13/2023]
Abstract
We present, to the best of our knowledge, the first demonstration of thermal, optical, and laser properties of Yb:GdScO3 for potentially efficient ultrashort pulse lasers. The stimulated emission cross section at 1025 nm (E//c) is 0.46×10-20cm2 with the emission band width of 85 nm, even broader than the well-known Yb:CaGdAlO4. It has quite a high thermal conductivity of 5.54W/(m⋅K) at 50°C, comparable with Yb:YAG. In the continuous-wave regime, the maximum output power of 13.45 W at 1063.9 nm was generated with the optical-to-optical efficiency of 63.3%. These results suggest that the Yb:GdScO3 crystal is a promising candidate for ultrashort pulse lasers.
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15
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Istomin SY, Lyskov NV, Mazo GN, Antipov EV. Electrode materials based on complex d-metal oxides for symmetrical solid oxide fuel cells. RUSSIAN CHEMICAL REVIEWS 2021. [DOI: 10.1070/rcr4979] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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16
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Chen Z, Jiang Y, Shao YT, Holtz ME, Odstrčil M, Guizar-Sicairos M, Hanke I, Ganschow S, Schlom DG, Muller DA. Electron ptychography achieves atomic-resolution limits set by lattice vibrations. Science 2021; 372:826-831. [DOI: 10.1126/science.abg2533] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 04/13/2021] [Indexed: 01/30/2023]
Affiliation(s)
- Zhen Chen
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY 14853, USA
| | - Yi Jiang
- Advanced Photon Source, Argonne National Laboratory, Lemont, IL 60439, USA
| | - Yu-Tsun Shao
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY 14853, USA
| | - Megan E. Holtz
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY, USA
| | | | | | - Isabelle Hanke
- Leibniz-Institut für Kristallzüchtung, Max-Born-Str. 2, 12489 Berlin, Germany
| | - Steffen Ganschow
- Leibniz-Institut für Kristallzüchtung, Max-Born-Str. 2, 12489 Berlin, Germany
| | - Darrell G. Schlom
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY, USA
- Leibniz-Institut für Kristallzüchtung, Max-Born-Str. 2, 12489 Berlin, Germany
- Kavli Institute at Cornell for Nanoscale Science, Ithaca, NY, USA
| | - David A. Muller
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY 14853, USA
- Kavli Institute at Cornell for Nanoscale Science, Ithaca, NY, USA
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17
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MacArthur KE, Yankovich AB, Béché A, Luysberg M, Brown HG, Findlay SD, Heggen M, Allen LJ. Optimizing Experimental Conditions for Accurate Quantitative Energy-Dispersive X-ray Analysis of Interfaces at the Atomic Scale. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2021; 27:1-15. [PMID: 33843542 DOI: 10.1017/s1431927621000246] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The invention of silicon drift detectors has resulted in an unprecedented improvement in detection efficiency for energy-dispersive X-ray (EDX) spectroscopy in the scanning transmission electron microscope. The result is numerous beautiful atomic-scale maps, which provide insights into the internal structure of a variety of materials. However, the task still remains to understand exactly where the X-ray signal comes from and how accurately it can be quantified. Unfortunately, when crystals are aligned with a low-order zone axis parallel to the incident beam direction, as is necessary for atomic-resolution imaging, the electron beam channels. When the beam becomes localized in this way, the relationship between the concentration of a particular element and its spectroscopic X-ray signal is generally nonlinear. Here, we discuss the combined effect of both spatial integration and sample tilt for ameliorating the effects of channeling and improving the accuracy of EDX quantification. Both simulations and experimental results will be presented for a perovskite-based oxide interface. We examine how the scattering and spreading of the electron beam can lead to erroneous interpretation of interface compositions, and what approaches can be made to improve our understanding of the underlying atomic structure.
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Affiliation(s)
- Katherine E MacArthur
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Peter Grünberg Institute, Forschungszentrum Jülich, Jülich52425, Germany
| | - Andrew B Yankovich
- Department of Physics, Chalmers University of Technology, SE-412 96Gothenburg, Sweden
| | - Armand Béché
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, 2020Antwerp, Belgium
| | - Martina Luysberg
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Peter Grünberg Institute, Forschungszentrum Jülich, Jülich52425, Germany
| | - Hamish G Brown
- National Centre for Electron Microscopy, the Molecular Foundry, Lawrence Berkeley National Lab, Berkeley, CA94720, USA
| | - Scott D Findlay
- School of Physics and Astronomy, Monash University, Clayton, VIC3800, Australia
| | - Marc Heggen
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Peter Grünberg Institute, Forschungszentrum Jülich, Jülich52425, Germany
| | - Leslie J Allen
- School of Physics, University of Melbourne, Parkville, VIC3010, Australia
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18
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Syntheses and Characterization of Novel Perovskite-Type LaScO 3-Based Lithium Ionic Conductors. Molecules 2021; 26:molecules26020299. [PMID: 33435543 PMCID: PMC7828101 DOI: 10.3390/molecules26020299] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 01/01/2021] [Accepted: 01/06/2021] [Indexed: 11/23/2022] Open
Abstract
Perovskite-type lithium ionic conductors were explored in the (LixLa1−x/3)ScO3 system following their syntheses via a high-pressure solid-state reaction. Phase identification indicated that a solid solution with a perovskite-type structure was formed in the range 0 ≤ x < 0.6. When x = 0.45, (Li0.45La0.85)ScO3 exhibited the highest ionic conductivity and a low activation energy. Increasing the loading of lithium as an ionic diffusion carrier expanded the unit cell volume and contributed to the higher ionic conductivity and lower activation energy. Cations with higher oxidation numbers were introduced into the A/B sites to improve the ionic conductivity. Ce4+ and Zr4+ or Nb5+ dopants partially substituted the A-site (La/Li) and B-site Sc, respectively. Although B-site doping produced a lower ionic conductivity, A-site Ce4+ doping improved the conductive properties. A perovskite-type single phase was obtained for (Li0.45La0.78Ce0.05)ScO3 upon Ce4+ doping, providing a higher ionic conductivity than (Li0.45La0.85)ScO3. Compositional analysis and crystal-structure refinement of (Li0.45La0.85)ScO3 and (Li0.45La0.78Ce0.05)ScO3 revealed increased lithium contents and expansion of the unit cell upon Ce4+ co-doping. The highest ionic conductivity of 1.1 × 10−3 S cm−1 at 623 K was confirmed for (Li0.4Ce0.15La0.67)ScO3, which is more than one order of magnitude higher than that of the (LixLa1−x/3)ScO3 system.
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19
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Klimm D, Guguschev C, Ganschow S, Bickermann M, Schlom DG. REScO
3
Substrates—Purveyors of Strain Engineering. CRYSTAL RESEARCH AND TECHNOLOGY 2019. [DOI: 10.1002/crat.201900111] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Detlef Klimm
- Leibniz‐Institut für Kristallzüchtung Max‐Born‐Str. 2 12489 Berlin Germany
| | - Christo Guguschev
- Leibniz‐Institut für Kristallzüchtung Max‐Born‐Str. 2 12489 Berlin Germany
| | - Steffen Ganschow
- Leibniz‐Institut für Kristallzüchtung Max‐Born‐Str. 2 12489 Berlin Germany
| | | | - Darrell G. Schlom
- Department of Materials Science and Engineering Cornell University Ithaca NY USA
- Kavli Institute at Cornell for Nanoscale Science Ithaca NY 14853‐1501 USA
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20
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Hachtel JA, Idrobo JC, Chi M. Sub-Ångstrom electric field measurements on a universal detector in a scanning transmission electron microscope. ADVANCED STRUCTURAL AND CHEMICAL IMAGING 2018; 4:10. [PMID: 30221126 PMCID: PMC6132373 DOI: 10.1186/s40679-018-0059-4] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Accepted: 08/09/2018] [Indexed: 11/25/2022]
Abstract
Scanning transmission electron microscopy (STEM) excels in accessing atomic-scale structure and chemistry. Enhancing our ability to directly image the functionalities of local features in materials has become one of the most important topics in the future development of STEM. Recently, differential phase contrast (DPC) imaging has been utilized to map the internal electric and magnetic fields in materials from nanoscale features such as p-n junctions, skyrmions, and even from individual atoms. Here, we use an ultra-low noise SCMOS detector in as the diffraction plane camera to collect four-dimensional (4D) datasets. The high angular resolution, efficient high-SNR acquisition, and modifiability of the camera allow it to function as a universal detector, where STEM imaging configurations, such as DPC, bright field, annular bright field, and annular dark field can all be reconstructed from a single 4D dataset. By examining a distorted perovskite, DyScO3, which possesses projected lattice spacings as small as 0.83 Å, we demonstrate DPC spatial resolution almost reaching the information limit of a 100 keV electron beam. In addition, the perovskite has ordered O-coordinations with alternating octahedral tilts, which can be quantitatively measured with single degree accuracy by taking advantage of DPC's sensitivity to light atoms. The results, acquired on a standard Ronchigram camera as opposed to a specialized DPC detector, open up new opportunities to understand and design functional materials and devices that involve lattice and charge coupling at nano- and atomic-scales.
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Affiliation(s)
- Jordan A. Hachtel
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Juan Carlos Idrobo
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Miaofang Chi
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
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21
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Paull RJ, Mansley ZR, Ly T, Marks LD, Poeppelmeier KR. Synthesis of Gadolinium Scandate from a Hydroxide Hydrogel. Inorg Chem 2018; 57:4104-4108. [PMID: 29561596 DOI: 10.1021/acs.inorgchem.8b00281] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Gadolinium scandate (GdScO3) has been synthesized at 300 °C through the decomposition of a mixed cation hydroxide hydrogel in a humid environment. Increasing the reaction temperature produced larger particles that better adopted the Wulff shape. A lack of water vapor during the synthesis caused the solid network of the hydrogel to collapse upon heating so an amorphous xerogel was produced. Water vapor in the system imbibed the hydrogel and allowed for greater diffusion of the atomic species to allow for crystallization into the perovskite phase at temperatures lower than typical sol-gel processes. Temperatures less than 300 °C, or an excess of water vapor, promoted the formation of Gd(OH)3 and ScOOH in addition to or in lieu of GdScO3.
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Affiliation(s)
- Ryan J Paull
- Department of Materials Science & Engineering , Northwestern University , Evanston , Illinois 60208 , United States
| | - Zachary R Mansley
- Department of Materials Science & Engineering , Northwestern University , Evanston , Illinois 60208 , United States
| | - Tiffany Ly
- Department of Materials Science & Engineering , Northwestern University , Evanston , Illinois 60208 , United States
| | - Laurence D Marks
- Department of Materials Science & Engineering , Northwestern University , Evanston , Illinois 60208 , United States
| | - Kenneth R Poeppelmeier
- Department of Materials Science & Engineering , Northwestern University , Evanston , Illinois 60208 , United States.,Department of Chemistry , Northwestern University , Evanston , Illinois 60208 , United States
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22
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Wu SQ, Cheng S, Lu L, Liu M, Jin XW, Cheng SD, Mi SB. B-site ordering and strain-induced phase transition in double-perovskite La 2NiMnO 6 films. Sci Rep 2018; 8:2516. [PMID: 29410424 PMCID: PMC5802844 DOI: 10.1038/s41598-018-20812-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 01/24/2018] [Indexed: 12/05/2022] Open
Abstract
The magnetic and electrical properties of complex oxide thin films are closely related to the phase stability and cation ordering, which demands that we understand the process-structure-property relationships microscopically in functional materials research. Here we study multiferroic thin films of double-perovskite La2NiMnO6 epitaxially grown on SrTiO3, KTaO3, LaAlO3 and DyScO3 substrates by pulsed laser deposition. The effect of epitaxial strains imposed by the substrate on the microstructural properties of La2NiMnO6 has been systematically investigated by means of advanced electron microscopy. It is found that La2NiMnO6 films under tensile strain exhibit a monoclinic structure, while under compressive strain the crystal structure of La2NiMnO6 films is rhombohedral. In addition, by optimizing the film deposition conditions a long-range ordering of B-site cations in La2NiMnO6 films has been obtained in both monoclinic and rhombohedral phases. Our results not only provide a strategy for tailoring phase stability by strain engineering, but also shed light on tuning B-site ordering by controlling film growth temperature in double-perovskite La2NiMnO6 films.
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Affiliation(s)
- Sheng-Qiang Wu
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Sheng Cheng
- School of Microelectronics, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Lu Lu
- School of Microelectronics, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Ming Liu
- School of Microelectronics, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Xiao-Wei Jin
- School of Microelectronics, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Shao-Dong Cheng
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, China.,School of Microelectronics, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Shao-Bo Mi
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, China.
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23
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Guguschev C, Hidde J, Gesing TM, Gogolin M, Klimm D. Czochralski growth and characterization of Tb xGd 1−xScO 3 and Tb xDy 1−xScO 3 solid-solution single crystals. CrystEngComm 2018. [DOI: 10.1039/c8ce00335a] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
TbxGd1−xScO3 and TbxDy1−xScO3 solid-solution single crystals were grown by the Czochralski method to validate the practicality of solid solutions between neighboring RE scandates (REScO3).
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Affiliation(s)
- C. Guguschev
- Leibniz Institute for Crystal Growth
- 12489 Berlin
- Germany
| | - J. Hidde
- Leibniz Institute for Crystal Growth
- 12489 Berlin
- Germany
| | - T. M. Gesing
- University of Bremen
- Solid State Chemical Crystallography
- Institute of Inorganic Chemistry and Crystallography
- 28359 Bremen
- Germany
| | - M. Gogolin
- University of Bremen
- Solid State Chemical Crystallography
- Institute of Inorganic Chemistry and Crystallography
- 28359 Bremen
- Germany
| | - D. Klimm
- Leibniz Institute for Crystal Growth
- 12489 Berlin
- Germany
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24
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Hirai K, Aso R, Ozaki Y, Kan D, Haruta M, Ichikawa N, Kurata H, Shimakawa Y. Melting of Oxygen Vacancy Order at Oxide-Heterostructure Interface. ACS APPLIED MATERIALS & INTERFACES 2017; 9:30143-30148. [PMID: 28791864 DOI: 10.1021/acsami.7b08134] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Modifications in oxygen coordination environments in heterostructures consisting of dissimilar oxides often emerge and lead to unusual properties of the constituent materials. Although lots of attention has been paid to slight modifications in the rigid oxygen octahedra of perovskite-based heterointerfaces, revealing the modification behaviors of the oxygen coordination environments in the heterostructures containing oxides with oxygen vacancies have been challenging. Here, we show that a significant modification in the oxygen coordination environments-melting of oxygen vacancy order-is induced at the heterointerface between SrFeO2.5 (SFO) and DyScO3 (DSO). When an oxygen-deficient perovskite (brownmillerite structure) SrFeO2.5 film grows epitaxially on a perovskite DyScO3 substrate, both FeO6 octahedra and FeO4 tetrahedra in the (101)-oriented SrFeO2.5 thin film connect to ScO6 octahedra in DyScO3. As a consequence of accommodating a structural mismatch, the alternately ordered arrangement of oxygen vacancies is significantly disturbed and reconstructed in the 2 nm thick heterointerface region. The stabilized heterointerface structure consists of Fe3+ octahedra with an oxygen vacancy disorder. The melting of the oxygen vacancy order, which in bulk SrFeO2.5 occurs at 1103 K, is induced at the present heterointerface at ambient temperatures.
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Affiliation(s)
- Kei Hirai
- Institute for Chemical Research, Kyoto University , Uji, Kyoto 611-0011, Japan
| | - Ryotaro Aso
- Institute for Chemical Research, Kyoto University , Uji, Kyoto 611-0011, Japan
| | - Yusuke Ozaki
- Institute for Chemical Research, Kyoto University , Uji, Kyoto 611-0011, Japan
| | - Daisuke Kan
- Institute for Chemical Research, Kyoto University , Uji, Kyoto 611-0011, Japan
| | - Mitsutaka Haruta
- Institute for Chemical Research, Kyoto University , Uji, Kyoto 611-0011, Japan
| | - Noriya Ichikawa
- Institute for Chemical Research, Kyoto University , Uji, Kyoto 611-0011, Japan
| | - Hiroki Kurata
- Institute for Chemical Research, Kyoto University , Uji, Kyoto 611-0011, Japan
| | - Yuichi Shimakawa
- Institute for Chemical Research, Kyoto University , Uji, Kyoto 611-0011, Japan
- Integrated Research Consortium on Chemical Sciences , Uji, Kyoto 611-0011, Japan
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25
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Large polarization gradients and temperature-stable responses in compositionally-graded ferroelectrics. Nat Commun 2017; 8:14961. [PMID: 28488672 PMCID: PMC5436105 DOI: 10.1038/ncomms14961] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Accepted: 02/16/2017] [Indexed: 11/13/2022] Open
Abstract
A range of modern applications require large and tunable dielectric, piezoelectric or pyroelectric response of ferroelectrics. Such effects are intimately connected to the nature of polarization and how it responds to externally applied stimuli. Ferroelectric susceptibilities are, in general, strongly temperature dependent, diminishing rapidly as one transitions away from the ferroelectric phase transition (TC). In turn, researchers seek new routes to manipulate polarization to simultaneously enhance susceptibilities and broaden operational temperature ranges. Here, we demonstrate such a capability by creating composition and strain gradients in Ba1−xSrxTiO3 films which result in spatial polarization gradients as large as 35 μC cm−2 across a 150 nm thick film. These polarization gradients allow for large dielectric permittivity with low loss (ɛr≈775, tan δ<0.05), negligible temperature-dependence (13% deviation over 500 °C) and high-dielectric tunability (greater than 70% across a 300 °C range). The role of space charges in stabilizing polarization gradients is also discussed. Future technologies based on ferroelectric materials will require new routes to control the nature of polar order. Through a combined experimental and theoretical study of compositionally and strain-graded Ba1-xSrxTiO3 heterostructures, Damodaran et al. demonstrate the ability to engineer large polarization gradients and temperature-stable susceptibilities.
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26
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Horák L, Kriegner D, Liu J, Frontera C, Marti X, Holý V. Structure of epitaxial SrIrO3 perovskite studied by interference between X-ray waves diffracted by the substrate and the thin film. J Appl Crystallogr 2017. [DOI: 10.1107/s1600576717000541] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023] Open
Abstract
A high-pressure metastable orthorhombic phase of SrIrO3 perovskite has been epitaxially stabilized on several substrates (DyScO3, GdScO3, NdScO3 and SrTiO3) in the form of thin monocrystalline layers with (110) surface orientation. The unit-cell parameters of the pseudomorphic thin SrIrO3 layers depend on the biaxial strain imposed by the various substrates due to the different lattice mismatches of the particular substrate and the bulk orthorhombic SrIrO3 structure. Using X-ray diffractometry, it is shown that both compressive and tensile strain increase the lattice parameters a and b, while the angle γ scales with the applied strain, being smaller or larger than 90° for compressive or tensile strain, respectively, resulting in a small monoclinic distortion of the layer unit cell. Owing to the similarity of the substrate and layer lattices, the diffraction signals from the two structures overlap partially, which complicates structure determination by standard refinement methods using measured integrated intensities. The measured signal is composed of two interfering components corresponding to the waves diffracted by the substrate and by the layer, where the first component is calculated exactly using the known substrate structure, while the second one is determined by the unknown unit-cell parameters of the layer. The unit-cell parameters were refined in order to fit the experimental data with the simulation. The fractional coordinates of the atoms in the unit cell resulting from the fit are similar to those in the bulk structure.
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27
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Damodaran AR, Agar JC, Pandya S, Chen Z, Dedon L, Xu R, Apgar B, Saremi S, Martin LW. New modalities of strain-control of ferroelectric thin films. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:263001. [PMID: 27187744 DOI: 10.1088/0953-8984/28/26/263001] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Ferroelectrics, with their spontaneous switchable electric polarization and strong coupling between their electrical, mechanical, thermal, and optical responses, provide functionalities crucial for a diverse range of applications. Over the past decade, there has been significant progress in epitaxial strain engineering of oxide ferroelectric thin films to control and enhance the nature of ferroelectric order, alter ferroelectric susceptibilities, and to create new modes of response which can be harnessed for various applications. This review aims to cover some of the most important discoveries in strain engineering over the past decade and highlight some of the new and emerging approaches for strain control of ferroelectrics. We discuss how these new approaches to strain engineering provide promising routes to control and decouple ferroelectric susceptibilities and create new modes of response not possible in the confines of conventional strain engineering. To conclude, we will provide an overview and prospectus of these new and interesting modalities of strain engineering helping to accelerate their widespread development and implementation in future functional devices.
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Affiliation(s)
- Anoop R Damodaran
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, California, USA
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28
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Belik AA, Yi W, Kumagai Y, Katsuya Y, Tanaka M, Oba F. LiNbO3-Type Oxide (Tl1–xScx)ScO3: High-Pressure Synthesis, Crystal Structure, and Electronic Properties. Inorg Chem 2016; 55:1940-5. [DOI: 10.1021/acs.inorgchem.5b02915] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Alexei A. Belik
- International Center for Materials Nanoarchitectonics
(WPI-MANA), National Institute for Materials Science (NIMS), Namiki
1-1, Tsukuba, Ibaraki 305-0044, Japan
| | - Wei Yi
- International Center for Materials Nanoarchitectonics
(WPI-MANA), National Institute for Materials Science (NIMS), Namiki
1-1, Tsukuba, Ibaraki 305-0044, Japan
- Institute
of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China
| | | | - Yoshio Katsuya
- Synchrotron
X-ray Station at SPring-8, NIMS, Kouto 1-1-1, Sayo-cho, Hyogo 679-5148, Japan
| | - Masahiko Tanaka
- Synchrotron
X-ray Station at SPring-8, NIMS, Kouto 1-1-1, Sayo-cho, Hyogo 679-5148, Japan
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29
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Sayed FN, Shukla R, Tyagi AK. A chemical method for stabilizing a new series of solid solution Pr1-xCexScO3 (0.0 ≤x≤ 1.0) systems. Dalton Trans 2015; 44:16929-36. [PMID: 26361068 DOI: 10.1039/c5dt01459j] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A new series of Pr1-xCexScO3 (0.0 ≤x≤ 1.0) compounds was synthesized by a two-step synthesis route, involving a combustion reaction followed by reduction while heating in a low partial pressure of O2, generated by a zirconium sponge that acts as an oxygen getter. For the first time, perovskite solid solution formation was observed in this series in the entire homogeneity range. These compounds were characterized using XRD, Raman spectroscopy and DRUV-visible spectroscopy. Rietveld refinement was carried out on the XRD data to determine unit cell parameters, bond lengths, bond angles along with the tilt angles for ScO6 octahedra. The analyses of the Raman shift were also in agreement with the XRD data. All compounds in this series showed a decreasing trend in the bandgap from 4.74 to 2.91 eV as a function of increasing Ce(3+) concentration.
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Affiliation(s)
- Farheen N Sayed
- Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085, India.
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30
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Baszczuk A, Dabrowski B, Avdeev M. High temperature neutron diffraction studies of PrInO3 and the measures of perovskite structure distortion. Dalton Trans 2015; 44:10817-27. [PMID: 25760430 DOI: 10.1039/c4dt03881a] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The crystal structure of PrInO(3) was investigated in the temperature range 303-1123 K by high-resolution neutron-powder diffraction. The PrInO(3) adopts a highly distorted variant of the perovskite structure with the orthorhombic Pnma space group in the whole temperature range investigated. The bond length and bond-angle analysis revealed a very slow tendency to decrease structural distortion with increasing temperature. Comparison of different parameters quantifying perovskite structure distortion calculated for PrInO(3) and the similar PrAlO(3) and PrGaO(3) shows the advantage of using the tolerance factor t12 calculated for the 12-fold coordinated Pr by geometrical averaging of the individual interatomic distances. An additional advantage of the tolerance factor method results from the possibility of extending it to predict the average structural distortion and the geometrical stability of the perovskites at various temperatures once the accurate dependence of t(x,T,d) on the composition, temperature and oxygen content is found. By comparing PrInO(3) with several AMO(3) perovskites containing ions in the fixed oxidation state on the A and M crystal sites it was found that structural distortion and the tolerance factor t12 for PrInO(3) are consistent with the empirical thermal expansion coefficient based on the bond strength calculation [R. M. Hazen, and C. T. Prewitt, Am. Mineral., 1977, 62(3-4), 309]. In contrast to perovskites AMO(3-d) containing mixed-valent M ions, which allow for a wide range of changes of the tolerance factor t(12)(T,d) as a function of oxygen content, perovskites AMO(3) with M ions in the fixed oxidation state show much less flexibility. This flexibility is further reduced for the A(3+)M(3+)O(3) perovskites like PrInO(3) for which even a large change of the synthesis temperature has a minor effect on controlling the resulting t(12)(T) and the structural phase in comparison with A(2+)M(4+)O3 perovskites. The only parameter left for A(3+)M(3+)O(3) materials allowing formation of various perovskites and hexagonal phases is the total pressure, which may significantly change t(12)(T,P).
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Affiliation(s)
- A Baszczuk
- Wroclaw University of Technology, Department of Mechanics, Materials Science and Engineering, 50-370 Wroclaw, Poland.
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31
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Atuchin VV, Aleksandrovsky AS, Chimitova OD, Diao CP, Gavrilova TA, Kesler VG, Molokeev MS, Krylov AS, Bazarov BG, Bazarova JG, Lin Z. Electronic structure of β-RbSm(MoO4)2 and chemical bonding in molybdates. Dalton Trans 2015; 44:1805-15. [DOI: 10.1039/c4dt03203a] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Microcrystals of orthorhombic rubidium samarium molybdate, β-RbSm(MoO4)2, have been fabricated by solid state synthesis at T = 450 °C, 70 h, and at T = 600 °C, 150 h.
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32
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Kan D, Aso R, Kurata H, Shimakawa Y. Phase control of a perovskite transition-metal oxide through oxygen displacement at the heterointerface. Dalton Trans 2015; 44:10594-607. [DOI: 10.1039/c4dt03749a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We overview investigations highlighting the significance of interface engineering of oxygen displacement as a tool for phase control of strained oxides.
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Affiliation(s)
- Daisuke Kan
- Institute for Chemical Research
- Kyoto University
- Uji
- Japan
| | - Ryotaro Aso
- Institute for Chemical Research
- Kyoto University
- Uji
- Japan
| | - Hiroki Kurata
- Institute for Chemical Research
- Kyoto University
- Uji
- Japan
| | - Yuichi Shimakawa
- Institute for Chemical Research
- Kyoto University
- Uji
- Japan
- Japan Science and Technology Agency
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Is there a Stobbs factor in atomic-resolution STEM-EELS mapping? Ultramicroscopy 2014; 139:38-46. [DOI: 10.1016/j.ultramic.2014.01.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Revised: 01/07/2014] [Accepted: 01/17/2014] [Indexed: 11/24/2022]
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Iturbe-Zabalo E, Igartua JM, Larrañaga A, Pomjakushin V, Castro G, Cuello GJ. Structural study of SrPrZnRuO₆, SrPrCoRuO₆, SrPrMgRuO₆ and SrPrNiRuO₆ double perovskite oxides by symmetry-adapted mode analysis. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2013; 25:205401. [PMID: 23603489 DOI: 10.1088/0953-8984/25/20/205401] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Powder SrPrZnRuO6, SrPrCoRuO6, SrPrMgRuO6 and SrPrNiRuO6 double perovskites were synthesized by the solid-state reaction method, and their crystal structure was investigated by Rietveld analysis (using the symmetry-mode procedure) by x-ray, synchrotron and neutron powder diffraction data. SrPrMRuO6 materials are monoclinic perovskites at room temperature, adopting the space group P21/n, [Formula: see text], c ≈ 2ap, Z = 2. The unit cell parameters increase through the series as the B-cation size increases. The tilting of the octahedra is associated with irreducible representations GM(+)4 and X(+)3. In the studied series, Sr(2+)/Pr(3+) are in eight-fold coordination and are displaced from the center of the Sr/PrO8 polyhedron along [010] by the X(+)5(A10) mode. The size of the first coordination sphere of Sr/Pr increases and the second coordination sphere reduces with temperature, suggesting an actual change in coordination. While changing the interatomic distances, the distortion of the structure diminishes, as observed in distortion mode amplitudes and octahedral tilt angles. The temperature driven [Formula: see text] phase transition was observed for Ni and Mg materials at ≈1025 K and 950 K, respectively. Tilting of the octahedra in the trigonal phase is associated with GM(+)4, which is the unique active mode associated with the not experimentally observed [Formula: see text] phase transition.
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Affiliation(s)
- E Iturbe-Zabalo
- Fisika Aplikatua II Saila, Zientzia eta Teknologia Fakultatea, UPV/EHU, PO Box 644, E-48080 Bilbao, Spain.
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Iturbe-Zabalo E, Igartua J, Aatiq A, Pomjakushin V. A structural study of the CaLn2CuTi2O9 (Ln=Pr, Nd, Sm) and BaLn2CuTi2O9 (Ln=La, Pr, Nd) triple perovskite series. J Mol Struct 2013. [DOI: 10.1016/j.molstruc.2012.08.049] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Xin HL, Zhu Y, Muller DA. Determining on-axis crystal thickness with quantitative position-averaged incoherent bright-field signal in an aberration-corrected STEM. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2012; 18:720-727. [PMID: 22559748 DOI: 10.1017/s1431927612000189] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
An accurate determination of specimen thickness is essential for quantitative analytical electron microscopy. Here we demonstrate that a position-averaged incoherent bright-field signal recorded on an absolute scale can be used to determine the thickness of on-axis crystals with a precision of ±1.6 nm. This method measures both the crystalline and the noncrystalline parts (surface amorphous layers) of the sample. However, it avoids the systematic error resulting from surface plasmon contributions to the inelastic mean-free-path thickness estimated by electron energy loss spectroscopy.
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Affiliation(s)
- Huolin L Xin
- Department of Physics, Cornell University, Ithaca, NY 14853, USA.
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Synthesis of perovsite-type oxide catalysts, Ln(Fe, Co)O3 (Ln=La, Pr, Sm, Gd, Dy, Ho, Er, and Yb), from the thermal decomposition of the corresponding cyano complexes. Catal Today 2012. [DOI: 10.1016/j.cattod.2011.09.023] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Schmidbauer M, Kwasniewski A, Schwarzkopf J. High-precision absolute lattice parameter determination of SrTiO3, DyScO3 and NdGaO3 single crystals. ACTA CRYSTALLOGRAPHICA SECTION B: STRUCTURAL SCIENCE 2012; 68:8-14. [DOI: 10.1107/s0108768111046738] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2011] [Accepted: 11/05/2011] [Indexed: 11/10/2022]
Abstract
The lattice parameters of three perovskite-related oxides have been measured with high precision at room temperature. An accuracy of the order of 10−5 has been achieved by applying a sophisticated high-resolution X-ray diffraction technique which is based on the modified Bond method. The results on cubic SrTiO3 [a = 3.905268 (98) Å], orthorhombic DyScO3 [a = 5.442417 (54), b = 5.719357 (52) and c = 7.904326 (98) Å], and orthorhombic NdGaO3 [a = 5.428410 (54), b = 5.498407 (55) and c = 7.708878 (95) Å] are discussed in view of possible systematic errors as well as non-stoichiometry in the crystals.
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Hayes JR, Grosvenor AP. An x-ray absorption spectroscopic study of the electronic structure and bonding of rare-earth orthoferrites. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2011; 23:465502. [PMID: 22056809 DOI: 10.1088/0953-8984/23/46/465502] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Rare-earth orthoferrites, REFeO₃ (RE D rare earth; Y), are tremendously adaptable compounds that are being investigated for use in a wide variety of applications including gas sensors, vehicle catalytic converters, and solid-oxide fuel cells. They also exhibit interesting magnetic properties such as high-temperature antiferromagnetism, making them useful for data storage applications. The compounds adopt a distorted perovskite-type structure where the tilt angle of the octahedra increases (Fe-O-Fe bond angle decreases) as the size of the rare-earth atom decreases. Despite intensive study of the physical properties of these compounds, very few studies have investigated how the bonding and electronic structure of these systems change with substitution of the RE. X-ray absorption near-edge spectroscopy (XANES) is a technique well-suited for such a study, and, in view of this, Fe L-, Fe K- and O K-edge spectra from a series of REFeO₃ compounds (RE D La, Pr, Nd, Sm, Eu, Gd, Ho, Yb, Y) have been collected, and are presented here. Fe L-edge spectra show that Fe is octahedrally coordinated and that the Fe-centered octahedra do not appear to distort with changes in the identity of the RE. The Fe K-edge spectra contain an intersite hybrid peak, which is an ill-studied feature that is attributed to non-local transitions of 1s electrons to 3d states on the next-nearest-neighbor atom that are hybridized with 4p states on the absorbing atom through O 2p states. In this study, it is shown that the intensity of this feature is strongly dependent on the Fe-O-Fe bond angle; the lower the Fe-O-Fe bond angle, the less intense the intersite hybrid peak is.
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Affiliation(s)
- J R Hayes
- Department of Chemistry, University of Saskatchewan, Saskatoon, SK S7N5C9, Canada
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Ferrarelli MC, Tan CC, Sinclair DC. Ferroelectric, electrical, and structural properties of Dy and Sc co-doped BaTiO3. ACTA ACUST UNITED AC 2011. [DOI: 10.1039/c0jm04429f] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Myllymäki P, Roeckerath M, Lopes JM, Schubert J, Mizohata K, Putkonen M, Niinistö L. Rare earth scandate thin films by atomic layer deposition: effect of the rare earth cation size. ACTA ACUST UNITED AC 2010. [DOI: 10.1039/c0jm00363h] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Veličkov B, Kahlenberg V, Bertram R, Bernhagen M. Crystal chemistry of GdScO3, DyScO3, SmScO3 and NdScO3. ACTA ACUST UNITED AC 2009. [DOI: 10.1524/zkri.2007.222.9.466] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The crystal chemistry of GdScO3 and, for the first time, of DyScO3, SmScO3 and NdScO3 has been investigated using single crystals. The structure of the Czochralski grown crystals was refined from single crystal X-ray diffraction data, their chemical compositions were analysed by inductively coupled plasma optical emission spectrometry (ICP OES). Orthorhombic distorted perovskite structure types with the space group Pnma could be confirmed in all cases. The B-site of the lanthanoid scandates shows with 2.090 to 2.116 Å typical bond lengths for octahedrally coordinated scandium. The distortion of the B-site is rather small. The A-site is occupied by the lanthanoid (Ln) and the Ln—O bond distances vary from 2.233 to 3.722 Å. This indicates its high distortion and makes an assignment of the coordination number difficult. However, an 8-fold coordination for the A-site has to be assumed. The Ln-scandates show a continuous structural evolution with the size of the lanthanoid. A discontinuity within the intermediate members of the Ln-scandates — which had previously been described — was not observed. The ICP OES investigation of these samples results in non-stoichiometric chemical compositions: the chemical analyses show always a depletion in the lanthanoid. Site occupancy refinements based on single crystal diffraction data support the idea of the Ln-depletion on the A-site (inducing O-defects on the O2-position). Several substitution mechanisms are discussed, but the authors favour that vacancies on the A-site coupled with oxygen vacancies cause the Ln-deficiencies. The crystallochemical formula of the investigated Ln-scandates may be written as: (∀0.056Dy0.944)ScO2.916,(∀0.048Gd0.952)ScO2.928, (∀0.045Sm0.955)ScO2.933 and (∀0.033Nd0.967)ScO2.951.
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Kahlenberg V, Maier D, Veličkov B. Redetermination of EuScO(3). Acta Crystallogr Sect E Struct Rep Online 2009; 65:i8. [PMID: 21581742 PMCID: PMC2968298 DOI: 10.1107/s1600536809001433] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2008] [Accepted: 01/12/2009] [Indexed: 11/17/2022]
Abstract
Single crystals of europium(III) scandate(III), with ideal formula EuScO3, were grown from the melt using the micro-pulling-down method. The title compound crystallizes in an orthorhombic distorted perovskite-type structure, where Eu occupies the eightfold coordinated A sites (site symmetry m) and Sc resides on the centres of corner-sharing [ScO6] octahedra (B sites with site symmetry ). The structure of EuScO3 has been reported previously based on powder diffraction data [Liferovich & Mitchell (2004). J. Solid State Chem.177, 2188–2197]. The results of the current redetermination based on single-crystal diffraction data shows an improvement in the precision of the structral and geometric parameters and reveals a defect-type structure. Site-occupancy refinements indicate an Eu deficiency on the A site coupled with O defects on one of the two O-atom positions. The crystallochemical formula of the investigated sample may thus be written as A(□0.032Eu0.968)BScO2.952.
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Veličkov B, Kahlenberg V, Bertram R, Uecker R. Redetermination of terbium scandate, revealing a defect-type perovskite derivative. Acta Crystallogr Sect E Struct Rep Online 2008; 64:i79. [PMID: 21580815 PMCID: PMC2959553 DOI: 10.1107/s1600536808033394] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2008] [Accepted: 10/14/2008] [Indexed: 11/10/2022]
Abstract
The crystal structure of terbium(III) scandate(III), with ideal formula TbScO3, has been reported previously on the basis of powder diffraction data [Liferovich & Mitchell (2004 ▶). J. Solid State Chem.177, 2188–2197]. The current data were obtained from single crystals grown by the Czochralski method and show an improvement in the precision of the geometric parameters. Moreover, inductively coupled plasma optical emission spectrometry studies resulted in a nonstoichiometric composition of the title compound. Site-occupancy refinements based on diffraction data support the idea of a Tb deficiency on the A site (inducing O defects on the O2 position). The crystallochemical formula of the investigated sample thus may be written as A(□0.04Tb0.96)BScO2.94. In the title compound, Tb occupies the eightfold-coordinated sites (site symmetry m) and Sc the centres of corner-sharing [ScO6] octahedra (site symmetry ). The mean bond lengths and site distortions fit well into the data of the remaining lanthanoid scandates in the series from DyScO3 to NdScO3. A linear structural evolution with the size of the lanthanoid from DyScO3 to NdScO3 can be predicted.
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Kuzmanovski I, Dimitrovska-Lazova S, Aleksovska S. Classification of perovskites with supervised self-organizing maps. Anal Chim Acta 2007; 595:182-9. [PMID: 17605999 DOI: 10.1016/j.aca.2007.04.062] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2006] [Revised: 04/17/2007] [Accepted: 04/24/2007] [Indexed: 11/17/2022]
Abstract
In this work supervised self-organizing maps were used for structural classification of perovskites. For this purpose, structural data for total number of 286 perovskites, belonging to ABO3 and/or A2BB'O6 types, were collected from literature: 130 of these are cubic, 85 orthorhombic and 71 monoclinic. For classification purposes, the effective ionic radii of the cations, electronegativities of the cations in B-position, as well as, the oxidation states of these cations, were used as input variables. The parameters of the developed models, as well as, the most suitable variables for classification purposes were selected using genetic algorithms. Two-third of all the compounds were used in the training phase. During the optimization process the performances of the models were checked using cross-validation leave-1/10-out. The performances of obtained solutions were checked using the test set composed of the remaining one-third of the compounds. The obtained models for classification of these three classes of perovskite compounds show very good results. Namely, the classification of the compounds in the test set resulted in small number of discrepancies (4.2-6.4%) between the actual crystallographic class and the one predicted by the models. All these results are strong arguments for the validity of supervised self-organizing maps for performing such types of classification. Therefore, the proposed procedure could be successfully used for crystallographic classification of perovskites in one of these three classes.
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Affiliation(s)
- Igor Kuzmanovski
- Institute of Chemistry, Faculty of Natural Sciences and Mathematics, University Sts. Cyril and Methodius, P.O. Box 162, 1001 Skopje, Macedonia.
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Mitchell RH, Liferovich RP. A structural study of the perovskite series Na0.75Ln0.25Ti0.5Nb0.5O3. J SOLID STATE CHEM 2005. [DOI: 10.1016/j.jssc.2005.05.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Mitchell RH, Liferovich RP. A structural study of the perovskite series Ca1−Na Ti1−Ta O3. J SOLID STATE CHEM 2004. [DOI: 10.1016/j.jssc.2004.09.031] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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