Tuning piezoelectric properties through epitaxy of La2Ti2O7 and related thin films

Kaspar, Tiffany C.; Hong, Seungbum; Bowden, Mark E.; Varga, Tamás; Yan, Pengfei; Wang, Chongmin; Spurgeon, Steven R.; Comès, R.; Ramuhalli, Pradeep; Henager, Charles H.

doi:10.1038/s41598-018-21009-5

Cited by 18 publications

(12 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Nominally 50 nm‐thick epitaxial La 2 Ti 2 O 7 thin films were deposited on SrTiO 3 (110) substrates using pulsed laser deposition (PLD) and annealed in air, [ 5 ] as described in Section 4. Ion irradiations were performed using 1 MeV Zr + ions applied 7° off‐normal to three quadrants of the same 1 × 1 cm 2 sample, yielding four conditions spanning 0, 1, 2, and 4 displacements per atom (dpa).…”

Section: Resultsmentioning

confidence: 99%

“…As shown in Figure 1a,b, the heterostructure before irradiation is fully crystalline and epitaxial, consisting of large regions of the well‐ordered La 2 Ti 2 O 7 monoclinic perovskite‐like layered structure (vertical or horizontal stripe contrast that corresponds to the additional (110) oxygen planes that occur between every four perovskite‐like units of LTO [ 5 ] ), as well as some smaller regions of cubic perovskite LaTiO 3 , a feature present in the X‐ray diffraction data and lower magnification STEM images shown in Figures S1 and S2, Supporting Information. Despite the crystallographic complexity, we do not observe extended defects such as grain boundaries.…”

Section: Resultsmentioning

confidence: 99%

“…Nominally 50 nm‐thick epitaxial La 2 Ti 2 O 7 (LTO) thin films were deposited by pulsed laser deposition at 950 °C and 0.5 mTorr pO 2 on SrTiO 3 (110) substrates, as described previously. [ 5 ] Post‐deposition annealing at 1000 °C in air for 4 h was necessary to obtain the perovskite‐like layered structure (PLS) crystal phase. Annealing also resulted in an increase in surface roughness and, in some cases, voids within the film, due to bulk mass transfer during the annealing process.…”

Section: Methodsmentioning

confidence: 99%

“…[ 8 ] During thin film growth, additional kinetic and substrate constraints can further change the energy landscape of the system and the resultant phase distribution. [ 5,9 ] This structural flexibility allows the pyrochlores to preserve their overall crystallinity during disordering of the cation sublattice by external stimuli, such as electric fields and energetic ion bombardment, making them promising candidates for SOFCs and nuclear waste forms. [ 10–12 ] Recently, Kreller et al [ 13 ] have shown that ion irradiation may be used to controllably manipulate anti‐site defect populations and resulting ion conduction at a fundamental level.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Asymmetric Lattice Disorder Induced at Oxide Interfaces

Spurgeon

Kaspar

Shutthanandan

et al. 2020

Adv Materials Inter

Self Cite

View full text Add to dashboard Cite

range of tunable functionalities, such as conductivity and magnetism, that result from non-equilibrium growth conditions, are distinct from the bulk, and are heavily influenced by lattice disorder. [1] Order-disorder phase transitions are particularly important in A 2 B 2 O 7 compounds (where A and B are transition metal cations), which have been studied for use in solid oxide fuel cells (SOFCs), [2][3][4] advanced ferroelectric sensors, [5,6] and nuclear waste forms. [7] These materials represent model systems in which to examine the fundamental relationship between the introduction of point defects and lattice disorder, which together govern behavior.In the bulk, A 2 B 2 O 7 compounds can exhibit a range of structures from defected fluorite ( 3 Fd m) to cubic pyrochlore ( 3 Fd m) and monoclinic perovskite-like layered structure (P2 1 ), as the cation radius ratio (r A /r B ) increases. [8] During thin film growth, additional kinetic and substrate constraints can further change the energy landscape of the system and the resultant phase distribution. [5,9] This structural flexibility allows the pyrochlores to preserve their overall crystallinity during disordering of the cation sublattice by external stimuli, such as electric fields and energetic ion bombardment, making them promising candidates for SOFCs and nuclear waste forms. [10][11][12] Recently, Kreller et al. [13] have shown that ion irradiation may be used to controllably manipulate anti-site defect populations and resulting ion conduction at a fundamental level. Building upon this approach, ion irradiation applied to thin film heterostructures represents a promising route to examine how interface geometry and configuration mediate the evolution of local order. Furthermore, characterization using aberrationcorrected scanning transmission electron microscopy can provide direct insight into defect formation that can be linked to models.Decades of work on metals have shown that grain boundaries and other interfaces can significantly influence point defect transport and annihilation, [14] motivating the use of engineered nanostructured materials to mediate disordering processes. [15][16][17] While irradiation-induced structural disorder has been extensively studied in bulk pyrochlores, [7,12,18,19] less attention has been paid to the behavior of irradiated oxide thin film interfaces. Previous studies of epitaxial TiO 2 , [20,21] CeO 2 , [22,23] and BaTiO 3[24] films on SrTiO 3 have shown evidence for the presence of denuded zones in some interface configurations and not in others; these variations have been attributed to differences in defect kinetics and energetics of the interface and its component elements. The interface charge state Control of order-disorder phase transitions is a fundamental materials science challenge, underpinning the development of energy storage technologies such as solid oxide fuel cells and batteries, ultra-high temperature ceramics, and durable nuclear waste forms. At present, the development of promising complex oxides for these...

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Asymmetric Lattice Disorder Induced at Oxide Interfaces

Spurgeon

Kaspar

Shutthanandan

et al. 2020

Adv Materials Inter

Self Cite

View full text Add to dashboard Cite

show abstract

“…The target materials are then rapidly vaporized and deposited on the substrate as a thin film, as seen in Figure 3b. [ 25c,d,83 ] The use of noncontact laser heating effectively avoids sample contamination to provide films of high quality. In this regard, PLD technology has been widely utilized for preparing biomedical microdevices.…”

Section: Synthesis and Modification Strategiesmentioning

confidence: 99%

Construction of Bio‐Piezoelectric Platforms: From Structures and Synthesis to Applications

et al. 2021

View full text Add to dashboard Cite

Piezoelectric materials, with their unique ability for mechanical‐electrical energy conversion, have been widely applied in important fields such as sensing, energy harvesting, wastewater treatment, and catalysis. In recent years, advances in material synthesis and engineering have provided new opportunities for the development of bio‐piezoelectric materials with excellent biocompatibility and piezoelectric performance. Bio‐piezoelectric materials have attracted interdisciplinary research interest due to recent insights on the impact of piezoelectricity on biological systems and their versatile biomedical applications. This review therefore introduces the development of bio‐piezoelectric platforms from a broad perspective and highlights their design and engineering strategies. State‐of‐the‐art biomedical applications in both biosensing and disease treatment will be systematically outlined. The relationships between the properties, structure, and biomedical performance of the bio‐piezoelectric materials are examined to provide a deep understanding of the working mechanisms in a physiological environment. Finally, the development trends and challenges are discussed, with the aim to provide new insights for the design and construction of future bio‐piezoelectric materials.

show abstract