Size Effects and Domains in Ferroelectric Thin Film Actuators

1996 ◽  
Vol 433 ◽  
Author(s):  
S. Trolier-Mckinstry ◽  
C. A. Randall ◽  
J. P. Maria ◽  
C. Theis ◽  
D. G. Schlom ◽  
...  
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Domain Walls ◽  
Sol Gel ◽  
Ferroelectric Thin Film ◽  
Ferroelectric Thin Films ◽  
Grain Sizes ◽  
Average Grain Size ◽  
Ferroelectric Domains ◽  
Gel Processing

AbstractFerroelectric thin films typically differ from bulk ceramics in terms of both the average grain size and the degree of stress imposed on the film by the substrate. Studies on bulk ceramics have demonstrated that the number of domain variants within grains depends on the grain size for sizes <˜lμm. This can diminish the poling efficiency of the material. Since most thin films show primary grain sizes well below a micron, similar effects should be observed in films. In addition, since the perovskite ferroelectrics contain ferroelastic as well as ferroelectric domains, it seems clear that stress in thin films may markedly alter the degree to which domain walls contribute to the observed properties. In this paper, the relative importance of these factors are discussed for several types of ferroelectric thin films. Films have been prepared by pulsed laser deposition, magnetron sputtering, and by sol-gel processing. It has been found that epitaxial BaTiO3 films are ferroelectric at 77K down to thicknesses as low as ˜ 60nm. Data on the low and high field electrical properties are reported as a function of temperature, the film crystallinity, and film thickness for representative perovskite films.

The Impact of Domains on the Dielectric and Electromechanical Properties of Ferroelectric Thin Films

1997 ◽  
Vol 493 ◽  
Author(s):  
S. Trolier-McKinstry ◽  
P. Aungkavattana ◽  
F. Chu ◽  
J. Lacey ◽  
J-P. Maria ◽  
...  
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Domain Walls ◽  
Sol Gel ◽  
Ferroelectric Thin Films ◽  
Piezoelectric Response ◽  
Electromechanical Properties ◽  
Phase Switching ◽  
Pzt Films ◽  
The Impact

ABSTRACTIn ferroelectric thin films for capacitive and piezoelectric applications, it is important to understand which mechanisms contribute to the observed dielectric constant and piezoelectricity. In soft PZT (PbZr1−xTixO3) ceramics, over half the room temperature response is associated with domain wall contributions to the properties. However, recent studies on bulk ceramics have demonstrated that the number of domain variants within grains, and the mobility of the twin walls depend on the grain size. This leads to a degradation in the dielectric and piezoelectric properties for grain sizes below a micron. This has significant consequences for thin films since a lateral grain size of 1 μm is often the upper limit on the observed grain size. In addition, since the pertinent domain walls are ferroelastic, the stress imposed on the film by the substrate could also clamp the piezoelectric response. To investigate these factors, controlled stress levels were imposed on PZT films of different thickness while the dielectric and electromechanical properties were measured. It was found that for undoped sol-gel PZT 40/60, 52/48, and 60/40 thin films under a micron in thickness, the extrinsic contributions to the dielectric and electromechanical properties make very modest contributions to the film response. No significant enhancement in the properties was observed even when the film was brought through the zero global stress condition. Comparable results were obtained from laser ablated films grown from hard and soft PZT targets. Finally, little twin wall mobility was observed in AFM experiments. The consequences of this in terms of the achievable properties in PZT films will be presented. Work on circumventing these limitations via utilization of antiferroelectric phase switching films and relaxor ferroelectric single crystal films will also be discussed.

LiNiO2 Thin Films Fabricated by Diffusion of Li on Ni Tapes

2007 ◽  
Vol 336-338 ◽  
pp. 505-508
Author(s):  
Cheol Jin Kim ◽  
In Sup Ahn ◽  
Kwon Koo Cho ◽  
Sung Gap Lee ◽  
Jun Ki Chung
Keyword(s):  
Thin Films ◽  
Heat Treatment ◽  
Grain Size ◽  
Sol Gel ◽  
Surface Oxidation ◽  
Cold Isostatic Pressing ◽  
Tube Furnace ◽  
Treatment Conditions ◽  
Average Grain Size ◽  
Cold Rolling And Annealing

LiNiO2 thin films for the application of cathode of the rechargeable battery were fabricated by Li ion diffusion on the surface oxidized NiO layer. Bi-axially textured Ni-tapes with 50 ~ 80 μm thickness were fabricated using cold rolling and annealing of Ni-rod prepared by cold isostatic pressing of Ni powder. Surface oxidation of Ni-tapes were conducted using tube furnace or line-focused infrared heater at 700 °C for 150 sec in flowing oxygen atmosphere, resulted in NiO layer with thickness of 400 and 800 μm, respectively. After Li was deposited on the NiO layer by thermal evaporation, LiNiO2 was formed by Li diffusion through the NiO layer during subsequent heat treatment using IR heater with various heat treatment conditions. IR-heating resulted in the smoother surface and finer grain size of NiO and LiNiO2 layer compared to the tube-furnace heating. The average grain size of LiNiO2 layer was 0.5~1 μm, which is much smaller than that of sol-gel processed LiNiO2. The reacted LiNiO2 region showed homogeneous composition throughout the thickness and did not show any noticeable defects frequently found in the solid state reacted LiNiO2, but crack and delamination between the reacted LiNiO2 and Ni occurred as the reaction time increased above 4hrs.

scholarly journals Effect of Solution Conditions on the Properties of Sol–Gel Derived Potassium Sodium Niobate Thin Films on Platinized Sapphire Substrates

Nanomaterials ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1600 ◽  
Author(s):  
Alexander Tkach ◽  
André Santos ◽  
Sebastian Zlotnik ◽  
Ricardo Serrazina ◽  
Olena Okhay ◽  
...  
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Low Cost ◽  
Sol Gel ◽  
Precursor Solution ◽  
Dissipation Factor ◽  
Solution Concentration ◽  
Potassium Sodium Niobate ◽  
Sapphire Substrates ◽  
Average Grain Size

If piezoelectric micro-devices based on K0.5Na0.5NbO3 (KNN) thin films are to achieve commercialization, it is critical to optimize the films’ performance using low-cost scalable processing conditions. Here, sol–gel derived KNN thin films are deposited using 0.2 and 0.4 M precursor solutions with 5% solely potassium excess and 20% alkali (both potassium and sodium) excess on platinized sapphire substrates with reduced thermal expansion mismatch in relation to KNN. Being then rapid thermal annealed at 750 °C for 5 min, the films revealed an identical thickness of ~340 nm but different properties. An average grain size of ~100 nm and nearly stoichiometric KNN films are obtained when using 5% potassium excess solution, while 20% alkali excess solutions give the grain size of 500–600 nm and (Na + K)/Nb ratio of 1.07–1.08 in the prepared films. Moreover, the 5% potassium excess solution films have a perovskite structure without clear preferential orientation, whereas a (100) texture appears for 20% alkali excess solutions, being particularly strong for the 0.4 M solution concentration. As a result of the grain size and (100) texturing competition, the highest room-temperature dielectric permittivity and lowest dissipation factor measured in the parallel-plate-capacitor geometry were obtained for KNN films using 0.2 M precursor solutions with 20% alkali excess. These films were also shown to possess more quadratic-like and less coercive local piezoelectric loops, compared to those from 5% potassium excess solution. Furthermore, KNN films with large (100)-textured grains prepared from 0.4 M precursor solution with 20% alkali excess were found to possess superior local piezoresponse attributed to multiscale domain microstructures.

PREPARATION AND STRUCTURE CHARACTERIZATION OF BiFeO3-SrBi2Nb2O9 THIN FILMS ON SILICON BY SOL-GEL PROCESSING

2002 ◽  
Vol 16 (28n29) ◽  
pp. 4455-4459
Author(s):  
HAOSHUANG GU ◽  
WANQIANG CAO ◽  
JUNMIN XUE ◽  
JOHN WANG
Keyword(s):  
Thin Films ◽  
Sol Gel ◽  
Precursor Solution ◽  
Monomethyl Ether ◽  
Structure Characterization ◽  
Layered Perovskite ◽  
Heat Treated ◽  
Average Grain Size ◽  
Gel Processing

A new system 0.1 BiFeO 3-0.9 SrBi 2 Nb 2 O 9 thin films have been successfully prepared by an ethanolamine-modified sol-gel technique. The precursor solution was synthesized from compounds, Bi(NO 3)3· 5H 2 O , Sr(NO 3)2, Fe(NO 3)3· 9H 2 O and Nb(OC 2 H 5)5 in solution ethylene glycol monomethyl ether. The thin films were deposited on Si single crystal by spinning coating, and heat-treated at temperatures ranging from 400°C to 700°C. Crystallization of thin films occurred at about 500 ~ 600°C and the films exhibit a pure phase of layered perovskite ferroelectric structure. The grain of films is well distributed and the average grain size of the film is about 100nm.

Effects of Annealing Temperature on Structure and Properties of PLBZT Ferroelectric Thin Films Synthesized by Sol-Gel Processing

2012 ◽  
Vol 602-604 ◽  
pp. 1461-1464
Author(s):  
Hua Wang ◽  
Li Liu ◽  
Ji Wen Xu ◽  
Ling Yang ◽  
Shang Ju Zhou
Keyword(s):  
Thin Films ◽  
Remanent Polarization ◽  
Annealing Temperature ◽  
Sol Gel ◽  
Pyrochlore Phase ◽  
Ferroelectric Thin Films ◽  
Structure And Properties ◽  
Maximum Value ◽  
Processing Effects ◽  
Gel Processing

[Pb0.95(La0.6Bi0.4)0.05][Zr0.53Ti0.47]O3 (PLBZT) ferroelectric thin films have been synthesized on ITO-coated glass by sol-gel processing. Effects of annealing temperature on structure and properties of PLBZT have been investigated. With the increase of annealing temperature from 500°C to 550°C, the remanent polarization Pr increase slightly to the maximum value of 25.4μC/cm2 due to the improvement in crystallization of PLBZT films. However, when the annealing temperature is more than 550°C, the pyrochlore phase appear and degrade the Pr of PLBZT thin films. The lowest leakage current density of 1.8×10-9 A/cm2 can be observed in PLBZT thin films when the annealing temperature is 550°C.

Preparation of PZT ferroelectric thin films by sol—gel processing and their properties

1995 ◽  
Vol 49 (3) ◽  
pp. 191-194 ◽  
Author(s):  
Liu Meidong ◽  
Lu Chunru ◽  
Wang Peiying ◽  
Rao Yunhua ◽  
Zeng Yike ◽  
...  
Keyword(s):  
Thin Films ◽  
Sol Gel ◽  
Ferroelectric Thin Films ◽  
Pzt Ferroelectric Thin Films ◽  
Gel Processing

Domain structures in Pb(Zr, Ti)O3 and PbTiO3 thin films

1997 ◽  
Vol 12 (10) ◽  
pp. 2612-2616 ◽  
Author(s):  
L. D. Madsen ◽  
E. M. Griswold ◽  
L. Weaver
Keyword(s):  
Thin Films ◽  
Classification Scheme ◽  
Sol Gel ◽  
Chemical Vapor ◽  
Nucleation And Growth ◽  
Grain Sizes ◽  
Domain Structures ◽  
Transmission Electron ◽  
20 Nm ◽  
Gel Processing

The microstructure of Pb(Zr, Ti)O3 (PZT) and PbTiO3 (PT) thin films deposited by the sol-gel method and chemical vapor deposition, respectively, were examined by transmission electron microscopy (TEM). Domains with ∼7 and ∼20 nm widths were found for the PZT and PT thin films, respectively. The traditional parallel twin or wedge-type structures found in bulk ceramics have been observed in thin films. Differences between observed grain sizes and previous studies of similar compounds (in bulk form) are accounted for by geometrical considerations related to crystallographic factors. Finally, a classification scheme for domains in PZT and PT thin films based on these and other published results of several researchers is presented. Domain sizes varied according to three categories: mono-domains (2–50 nm in diameter), domains in spherulite lamellae (28–130 nm wide), and twins in conventional large grains (5–150 nm wide). The mono-domains are related to small grain sizes, while the lamellae are a function of the nucleation and growth associated with sol-gel processing.

Morphology and Domain Structure of Unsupported PbTiO3Thin Films Prepared by Sol-Gel Process

1995 ◽  
Vol 403 ◽  
Author(s):  
C. J. Lu ◽  
S. B. Ren ◽  
H. M. Shen ◽  
Y. N. Wang
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Domain Structure ◽  
Domain Walls ◽  
Sol Gel ◽  
Single Domain ◽  
Annealing Temperatures ◽  
Sol Gel Process ◽  
Size And Morphology ◽  
Almost All

AbstractThe morphology and domain structure of unsupported PbTiO3thin films with fine grains (>200 nm) were investigated by TEM technique. The unsupported PbTiO3thin films were successfully prepared by sol-gel process onto NaCI substrates and followed by dissolving away the substrates. Electron diffiraction patterns showed that the unsupported PbTiO3thin films had slight <110> preferred orientation perpendicular to the film surfaces. Grain size and morphology vary significantly with the thickness of the films or the annealing temperatures. Even though the grain size is rather small (40–180 nm), the domains are clearly visible. Most of the grains show single domain, while some irregular and curved domain walls appear only in a small portion of the fine grains. The number of single-domained grains increases with decreasing grain size. Almost all domain walls observed are 90° walls.

Ferroelectric thin films prepared by sol-gel processing

1992 ◽  
Vol 1 (1) ◽  
pp. 17-42 ◽  
Author(s):  
Yuhuan Xu ◽  
John D Mackenzie
Keyword(s):  
Thin Films ◽  
Sol Gel ◽  
Ferroelectric Thin Films ◽  
Gel Processing
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