Abnormal Poisson's ratio and Linear Compressibility in Perovskite Materials

Huang, Chuanwei; Ren, Wei; Nguyen, Viet Cuong; Chen, Zuhuang; Wang, Junling; Sritharan, Thirumany; Chen, Lang

doi:10.1002/adma.201104676

Cited by 51 publications

(44 citation statements)

References 51 publications

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“…This behavior can be explained within the framework of the linear theory of elasticity. 53 However, while the experimentally determined DV/V for the compressively strained films on NdGaO 3 can be verified by typical Poisson ratios for perovskites, 54 the observed volume changes DV/V for the films under tensile strain are significantly higher than expected from elasticity theory. This deviation points to a slight oxygen deficiency in these films 55,56 and is attributed to the beneficial effect of the formation of oxygen vacancies in order to reduce the lattice mismatch for films which grow under tensile lattice strain.…”

Section: Partially Relaxed Films On Ndgaomentioning

confidence: 77%

Ferroelectric domain structure of anisotropically strained NaNbO3 epitaxial thin films

Schwarzkopf

Braun

Schmidbauer

et al. 2014

Journal of Applied Physics

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NaNbO3 thin films have been grown under anisotropic biaxial strain on several oxide substrates by liquid-delivery spin metalorganic chemical vapor deposition. Compressive lattice strain of different magnitude, induced by the deposition of NaNbO3 films with varying film thickness on NdGaO3 single crystalline substrates, leads to modifications of film orientation and phase symmetry, which are similar to the phase transitions in Pb-containing oxides near the morphotropic phase boundary. Piezoresponse force microscopy measurements exhibit large out-of-plane polarization components, but no distinctive domain structure, while C-V measurements indicate relaxor properties in these films. When tensile strain is provoked by the epitaxial growth on DyScO3, TbScO3, and GdScO3 single crystalline substrates, NaNbO3 films behave rather like a normal ferroelectric. The application of these rare-earth scandate substrates yields well-ordered ferroelectric stripe domains of the type a1/a2 with coherent domain walls aligned along the [001] substrate direction as long as the films are fully strained. With increasing plastic lattice relaxation, initially, a 2D domain pattern with still exclusively in-plane electric polarization, and finally, domains with in-plane and out-of-plane polar components evolve.

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Section: Partially Relaxed Films On Ndgaomentioning

confidence: 77%

Ferroelectric domain structure of anisotropically strained NaNbO3 epitaxial thin films

Schwarzkopf

Braun

Schmidbauer

et al. 2014

Journal of Applied Physics

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show abstract

“…As the increase in the oxygen 6 vacancies often results in lattice expansion for perovskite-typed complex oxides, we primarily attribute this deviation to the greater oxygen deficiency in the films with tensile strain; [28] otherwise, an unrealistic ν = 0.17 would be required from fully oxygenated films to fit the experimental data. [33] …”

Section: Structural Analysis Of Annealed Bm-sco and P-sco Filmsmentioning

confidence: 99%

Strain Control of Oxygen Vacancies in Epitaxial Strontium Cobaltite Films

Petrie

Mitra

Jeen

et al. 2016

Adv Funct Materials

215

160

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The ability to manipulate oxygen anion defects rather than metal cations in complex oxides is facilitating new functionalities critical for emerging energy and device technologies.However, the difficulty in activating oxygen at reduced temperatures hinders the deliberate control of an important defect, oxygen vacancies. Here, strontium cobaltite (SrCoO x ) is used to demonstrate that epitaxial strain is a powerful tool for manipulating the oxygen vacancy concentration even under highly oxidizing environments and at annealing temperatures as low as 300 °C. By applying a small biaxial tensile strain (2%), the oxygen activation energy barrier decreases by ~30%, resulting in a tunable oxygen deficient steady-state under conditions that would normally fully oxidize unstrained cobaltite. These strain-induced changes in oxygen stoichiometry drive the cobaltite from a ferromagnetic metal towards an antiferromagnetic insulator. The ability to decouple the oxygen vacancy concentration from its typical dependence on the operational environment is useful for effectively designing oxides materials with a specific oxygen stoichiometry.2

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“…For epitaxial BFO films, the in-plane misfit strain ε xx can change from compressive 6.8% to tensile 1.5% by choosing proper substrates (such as YAlO 3 , PrScO 3 ), which results in a sequence of structure deformations, phase transitions and occurrences of new properties of BFO films. In comparison with the thought positive constant, recent results reveal that the Poisson’s ratio (PR) in perovskites is an anisotropic variable [74]. This demonstrates that the PR of perovskites is highly sensitive to the crystallographic axes of materials and the value of it could become negative, zero or positive along certain directions.…”

Section: Effect Of Misfit Strain On Bfo Ultrathin Filmsmentioning

confidence: 99%

Effects of Interfaces on the Structure and Novel Physical Properties in Epitaxial Multiferroic BiFeO3 Ultrathin Films

Huang

Chen

2014

Materials

Self Cite

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In functional oxide films, different electrical/mechanical boundaries near film surfaces induce rich phase diagrams and exotic phenomena. In this paper, we review some key points which underpin structure, phase transition and related properties in BiFeO3 ultrathin films. Compared with the bulk counterparts, we survey the recent results of epitaxial BiFeO3 ultrathin films to illustrate how the atomic structure and phase are markedly influenced by the interface between the film and the substrate, and to emphasize the roles of misfit strain and depolarization field on determining the domain patterns, phase transformation and associated physical properties of BiFeO3 ultrathin films, such as polarization, piezoelectricity, and magnetism. One of the obvious consequences of the misfit strain on BiFeO3 ultrathin films is the emergence of a sequence of phase transition from tetragonal to mixed tetragonal & rhombohedral, the rhombohedral, mixed rhombohedral & orthorhombic, and finally orthorhombic phases. Other striking features of this system are the stable domain patterns and the crossover of 71° and 109° domains with different electrical boundary conditions on the film surface, which can be controlled and manipulated through the depolarization field. The external field-sensitive enhancements of properties for BiFeO3 ultrathin films, including the polarization, magnetism and morphotropic phase boundary-relevant piezoelectric response, offer us deeper insights into the investigations of the emergent properties and phenomena of epitaxial ultrathin films under various mechanical/electrical constraints. Finally, we briefly summarize the recent progress and list open questions for future study on BiFeO3 ultrathin films.

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Abnormal Poisson's ratio and Linear Compressibility in Perovskite Materials

Cited by 51 publications

References 51 publications

Ferroelectric domain structure of anisotropically strained NaNbO3 epitaxial thin films

Ferroelectric domain structure of anisotropically strained NaNbO3 epitaxial thin films

Strain Control of Oxygen Vacancies in Epitaxial Strontium Cobaltite Films

Effects of Interfaces on the Structure and Novel Physical Properties in Epitaxial Multiferroic BiFeO3 Ultrathin Films

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