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

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.

Author(s):  
J.M. Schwartz ◽  
L.F. Francis ◽  
L.D. Schmidt ◽  
P.S. Schabes-Retchkiman

Ceramic thin films and coatings are of interest for electrical, optical, magnetic and thermal barrier applications. Critical for improved properties in thin films is the development of specific microstructures during processing. To this end, the sol-gel method is advantageous as a versatile processing route. The sol-gel process involves depositing a solution containing metalorganic or colloidal ceramic precursors onto a substrate and heating the deposited layer to form a crystalline or non-crystalline ceramic coating. This route has several advantages, including the ability to create tailored microstructures and properties, to coat large or small areas, simple or complex shapes, and to more easily prepare multicomponent ceramics. Sol-gel derived coatings are amorphous in the as-deposited state and develop their crystalline structure and microstructure during heat-treatment. We are particularly interested in studying the amorphous to crystalline transformation, because many key features of the microstructure such as grain size and grain size distribution may be linked to this transformation.


2009 ◽  
Vol 471 (1-2) ◽  
pp. 511-514 ◽  
Author(s):  
Ru-Yuan Yang ◽  
Min-Hang Weng ◽  
Yan-Kuin Su ◽  
Chang-Sin Ye ◽  
Hung-Wei Wu

1996 ◽  
Vol 433 ◽  
Author(s):  
S. Trolier-Mckinstry ◽  
C. A. Randall ◽  
J. P. Maria ◽  
C. Theis ◽  
D. G. Schlom ◽  
...  

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.


2007 ◽  
Vol 21 (18n19) ◽  
pp. 3404-3411
Author(s):  
M. C. KAO ◽  
H. Z. CHEN ◽  
S. L. YOUNG ◽  
C. C. LIN ◽  
C. C. YU

LiTaO 3 thin films were deposited on Pt / Ti / SiO 2/ Si substrates by means of a sol-gel spin-coating technology and rapid thermal annealing (RTA). The influence of various annealing treatments on the characteristics of the thin films were studied by varying the single-annealed-layer thickness (50 ~ 200 nm ) and heating temperatures (500 ~ 800° C ) of the samples. Experimental results reveal that the single-annealed-layer strongly influences grain size, dielectricity and ferroelectricity of LiTaO 3 thin films. The grain size of LiTaO 3 thin film decreases slightly with increasing thickness of the single-annealed-layer, and highly c-axis orientated LiTaO 3 films can be obtained for a single-annealed-layer of 50 nm. When the thickness of the single-annealed-layer was increased from 50 to 200 nm, the relative dielectric constant of LiTaO 3 thin film decreased from 65 to 35, but the dielectric loss factor (tanδ) was increased. The LiTaO 3 films with the single-annealed-layer of 50 nm showed excellent ferroelectric properties in terms of a remanent polarization ( P r) of 12.3 μ C /cm2 (Ec ∼ 60 kV/cm), and a low current density of 5.2×l0-8 A /cm2 at 20 kV/cm.


1994 ◽  
Vol 361 ◽  
Author(s):  
Wan In Lee ◽  
J.K. Lee ◽  
Elsub Chung ◽  
C.W. Chung ◽  
I.K. Yoo ◽  
...  

ABSTRACTPZT (Zr/Ti = 53/47), PNZT (4% Nb doped PZT), PSZT (2% Sc doped PZT), and PSNZT (1% Sc and 1% Nb doped PZT) thin films were prepared by a sol-gel process. They were characterized by XRD, SEM and TEM. Both crystallographic orientation and grain size of PZT films can be changed by doping. Pt/PZT/Pt capacitors were fabricated for the measurement of ferroelectric properties. By doping with both Sc and Nb, the fatigue performance of the PZT films was considerably improved and the coercive field was decreased, while the remanent polarization was not changed. In addition, the effect of dopants on the leakage current level of PZT films was studied.


1997 ◽  
Vol 493 ◽  
Author(s):  
S. Trolier-McKinstry ◽  
P. Aungkavattana ◽  
F. Chu ◽  
J. Lacey ◽  
J-P. Maria ◽  
...  

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.


2013 ◽  
Vol 789 ◽  
pp. 101-104 ◽  
Author(s):  
Rachmat Andika ◽  
Muhammad Hikam

We studied the crystallographic of Barium Zirconium Titanate thin films with Aluminum doped (BZAT). These films were prepared by sol-gel process and followed by spin coating. The sintering temperature is taken at 800°C and 900°C. We found that the crystallographic system of BZAT thin films have tetragonal structure with the lattice parameter slightly changed by various Aluminum partial substitution. When 0.01 Al moles added, the grain size of the films is 29.42 nm at 800°C. The sintering temperature 900°C increased the grain size into 50.95 nm. We also calculated the spontaneous polarization theoretically and we found the optimum value of BZT thin film with 0.01 mole Al heated at 800°C, is 0.143 C/m2. This way, we could predict that the film has ferroelectric phase.


2004 ◽  
Vol 260 (1-2) ◽  
pp. 109-114 ◽  
Author(s):  
S.H. Hu ◽  
G.J. Hu ◽  
X.J. Meng ◽  
G.S. Wang ◽  
J.L. Sun ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document