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Domain topology and domain switching kinetics in a hybrid improper ferroelectric. Nat Commun 2016; 7:11602. [PMID: 27215944 PMCID: PMC4890185 DOI: 10.1038/ncomms11602] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 04/12/2016] [Indexed: 11/08/2022] Open
Abstract
Charged polar interfaces such as charged ferroelectric walls or heterostructured interfaces of ZnO/(Zn,Mg)O and LaAlO3/SrTiO3, across which the normal component of electric polarization changes suddenly, can host large two-dimensional conduction. Charged ferroelectric walls, which are energetically unfavourable in general, were found to be mysteriously abundant in hybrid improper ferroelectric (Ca,Sr)3Ti2O7 crystals. From the exploration of antiphase boundaries in bilayer-perovskites, here we discover that each of four polarization-direction states is degenerate with two antiphase domains, and these eight structural variants form a Z4 × Z2 domain structure with Z3 vortices and five distinct types of domain walls, whose topology is directly relevant to the presence of abundant charged walls. We also discover a zipper-like nature of antiphase boundaries, which are the reversible creation/annihilation centres of pairs of two types of ferroelectric walls (and also Z3-vortex pairs) in 90° and 180° polarization switching. Our results demonstrate the unexpectedly rich nature of hybrid improper ferroelectricity.
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Hu XL, Liu LH, Zhang Y, Lu GH, Wang T. Energy investigation of effects of O on mechanical properties of NiAl intermetallics. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2011; 23:025501. [PMID: 21406842 DOI: 10.1088/0953-8984/23/2/025501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We have investigated effects of O on mechanical properties of NiAl by calculating the cleavage energy (γ(C)) and the unstable stacking fault energy (γ(us)) using a first-principles method. O is shown to reduce γ(C)/γ(us) for the [001](110) and [100](001) slip systems, indicating that the presence of O should be associated with the ductility reduction of NiAl. Further, γ(C)/γ(us) of the NiAl-O system can be increased by Cr, suggesting the possibility to suppress the negative effect of O via alloying elements.
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Affiliation(s)
- Xue-Lan Hu
- Sino-European Institute of Aviation Engineering, Civil Aviation University of China, Tianjin 300300, People's Republic of China
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Hu XL, Zhang Y, Lu GH, Wang T. Bonding characteristics in NiAl intermetallics with O impurity: a first-principles computational tensile test. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2009; 21:025402. [PMID: 21813975 DOI: 10.1088/0953-8984/21/2/025402] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We have performed a first-principles computational tensile test on NiAl intermetallics with O impurity along the [001] crystalline direction on the (110) plane to investigate the tensile strength and the bonding characteristics of the NiAl-O system. We show that the ideal tensile strength is largely reduced due to the presence of O impurity in comparison with pure NiAl. The investigations of the atomic configuration and bond-length evolution show that O prefers to bond with Al, forming an O-Al cluster finally with the break of O-Ni bonds. The O-Ni bonds are demonstrated to be weaker than the O-Al bonds, and the reduced tensile strength originates from such weaker O-Ni bonds. A void-like structure forms after the break of the O-Ni and some Ni-Al bonds. Such a void-like structure can act as the initial nucleation or the propagation path of the crack, and thus produce large effects on the mechanical properties of NiAl.
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Affiliation(s)
- Xue-Lan Hu
- Department of Physics, Beijing University of Aeronautics and Astronautics, Beijing 100191, People's Republic of China
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Hu QM, Xu DS, Li D. First-principles investigations of the solute–vacancy interaction energy and its effect on the creep properties of α-titanium. ACTA ACUST UNITED AC 2007. [DOI: 10.1080/01418610108217166] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Parthasarathy TA, Rao SI, Dimiduk DM. Molecular statics simulations of core structures and motion of dislocations in NiAl. ACTA ACUST UNITED AC 2006. [DOI: 10.1080/01418619308207182] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
| | - S. I. Rao
- b National Research Council, WL/MLLM , Wright-Patterson Air Force Base, Ohio , 45433 , USA
| | - D. M. Dimiduk
- c Wright Laboratory, WL/MLLM , Wright-Patterson Air Force Base, Ohio , 45433 , USA
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Frommeyer G, Fischer R, Deges J, Rablbauer R, Schneider A. APFIM investigations on site occupancies of the ternary alloying elements Cr, Fe, and Re in NiAl. Ultramicroscopy 2004; 101:139-48. [PMID: 15450659 DOI: 10.1016/j.ultramic.2004.05.006] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2003] [Revised: 05/10/2004] [Accepted: 05/17/2004] [Indexed: 11/23/2022]
Abstract
The site occupancies of the transition metals Cr, Fe, and Re dissolved in NiAl of stoichiometric composition have been determined by atomic layer resolved atom probe field-ion microscopy (APFIM). The investigations were supported by X-ray diffraction studies to evaluate the lattice parameters. These are influenced by atomic size effects and constitutional lattice defects like Ni antistructure atoms in the Al sublattice and vacancies in the Ni sublattice. The APFIM results were compared with ALCHEMI data and calculated site preference energies published in the literature. Chromium additions to stoichiometric NiAl with 0.8 at% in solid solution exhibit a strong preference for Al sites. The lattice parameter of NiAl(Cr) solid solution is decreased. Iron atoms dissolved in higher concentrations of 5 at % in NiAl are almost equally distributed within both sublattices. They are possessing a weak preference for Al sites, which causes a lattice expansion of NiAl(Fe) solid solution. ALCHEMI results and site preference energy data show a strong site preference of Cr atoms for the Al sublattice. In contrast, iron atoms exhibit a weak site preference for Ni sites depending upon the stoichiometry of the NiAl host lattice. Re solutes in low concentrations of about 0.2 at % in NiAl possess a strong site preference for the Ni sublattice. The increase of the lattice parameter of NiAl(Re) is due to the pronounced size effect of Re atoms. For these species no ALCHEMI and site preference energy data are available in the literature.
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Affiliation(s)
- G Frommeyer
- Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Str. 1, P.O. Box 140444, D-40474 Düsseldorf, Germany
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Gschneidner K, Russell A, Pecharsky A, Morris J, Zhang Z, Lograsso T, Hsu D, Lo CHC, Ye Y, Slager A, Kesse D. A family of ductile intermetallic compounds. NATURE MATERIALS 2003; 2:587-591. [PMID: 12942069 DOI: 10.1038/nmat958] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2003] [Accepted: 07/10/2003] [Indexed: 05/24/2023]
Abstract
Stoichiometric intermetallic compounds have always been touted for their attractive chemical, physical, electrical, magnetic and mechanical properties, but few practical uses have materialized because they are brittle at room temperature. Here we report on a large family of fully ordered, stoichiometric binary rare-earth intermetallic compounds with high ductility at room temperature. Although conventional wisdom calls for special conditions, such as non-stoichiometry, metastable disorder or doping to achieve some ductility in intermetallic compounds at room temperature, none of these is required in these unique B2 rare-earth compounds. Ab initio calculations of YAg, YCu and NiAl crystal defect energies support the observed deformation modes of these intermetallics.
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Affiliation(s)
- Karl Gschneidner
- Ames Laboratory of the US DOE, 255 Spedding Hall, Iowa State University, Ames, Iowa 50011-3020, USA
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Kioussis N, Herbranson M, Collins E, Eberhart ME. Topology of electronic charge density and energetics of planar faults in fcc metals. PHYSICAL REVIEW LETTERS 2002; 88:125501. [PMID: 11909471 DOI: 10.1103/physrevlett.88.125501] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2001] [Indexed: 05/23/2023]
Abstract
Using ab initio calculations we have studied the energetics and the evolution of the electronic charge density with shear in three fcc metals exhibiting different deformation properties, aluminum, silver, and iridium. The charge redistribution described by the change in character of specific charge density critical points (cps), is ascertained from the values of the charge density, rho(0), and its three principal curvatures, rho( parallel parallel), rho(hh), and rho(vv), respectively. The change in character of cps correlates with the energetics. For all three metals, rho(hh) vanishes near the unstable stacking configuration. The symmetry or asymmetry of the charge redistribution, measured by rho(hh)/rho(vv), may be an important factor determining stacking fault energies.
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Affiliation(s)
- Nicholas Kioussis
- Department of Physics, California State University Northridge, Northridge, California 91330-8268, USA
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Fischer R, Frommeyer G, Schneider A. Atom Probe Field Ion Microscopy Investigations on Antiphase Boundaries and Super Dislocations in NiAl Alloyed with Chromium. ACTA ACUST UNITED AC 2001. [DOI: 10.1002/1521-396x(200107)186:1<115::aid-pssa115>3.0.co;2-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Medvedeva NI, Mryasov ON, Gornostyrev YN, Novikov DL, Freeman AJ. First-principles total-energy calculations for planar shear and cleavage decohesion processes in B2-ordered NiAl and FeAl. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 54:13506-13514. [PMID: 9985259 DOI: 10.1103/physrevb.54.13506] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Wu R, Zhong L, Chen L, Freeman AJ. First-principles determination of the tensile and slip energy barriers for B2 NiAl and FeAl. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 54:7084-7089. [PMID: 9984327 DOI: 10.1103/physrevb.54.7084] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Murty B, Joardar J, Pabi S. Influence of Fe and Cr on the disordering behavior of mechanically alloyed NiAl. ACTA ACUST UNITED AC 1996. [DOI: 10.1016/0965-9773(96)00032-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Fu CL. Origin of ordering in B2-type transition-metal aluminides: Comparative study of the defect properties of PdAl, NiAl, and FeAl. PHYSICAL REVIEW. B, CONDENSED MATTER 1995; 52:3151-3158. [PMID: 9981431 DOI: 10.1103/physrevb.52.3151] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Cotton JD, Noebe RD, Kaufman MJ. Nial-rich portion of the NiAl-Cr pseudobinary eutectic system. ACTA ACUST UNITED AC 1993. [DOI: 10.1007/bf02669138] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Singh DJ. Electronic structure, magnetism, and stability of Co-doped NiAl. PHYSICAL REVIEW. B, CONDENSED MATTER 1992; 46:14392-14397. [PMID: 10003537 DOI: 10.1103/physrevb.46.14392] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Schultz PA, Davenport JW. Bonding and brittleness in B2 structure 3d transition metal aluminides: Ionic, directional, or does it make a difference? ACTA ACUST UNITED AC 1992. [DOI: 10.1016/0956-716x(92)90352-f] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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MacLaren JM, Gonis A, Schadler G. First-principles calculation of stacking-fault energies in substitutionally disordered alloys. PHYSICAL REVIEW. B, CONDENSED MATTER 1992; 45:14392-14395. [PMID: 10001572 DOI: 10.1103/physrevb.45.14392] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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