Enhancement of Aurivillius Phase Formation Kinetics in SBT Thin Films using Nanoparticle Seeding

2003 ◽  
Vol 784 ◽  
Author(s):  
Yun-Mo Sung ◽  
Woo-Chul Kwak ◽  
Se-Yon Jung ◽  
Seung-Joon Hwang
Keyword(s):  
Thin Films ◽  
Activation Energy ◽  
Phase Transformation ◽  
Phase Formation ◽  
X Ray Diffraction ◽  
Aurivillius Phase ◽  
X Ray ◽  
Si Substrates ◽  
Formation Kinetics ◽  
Kinetics Of

ABSTRACTPt/Ti/SiO2/Si substrates seeded by SBT nanoparticles (∼60–80 nm) were used to enhance the phase formation kinetics of Sr0.7Bi2.4Ta2O9 (SBT) thin films. The volume fractions of Aurivillius phase formation obtained through quantitative x-ray diffraction (Q-XRD) analyses showed highly enhanced kinetics in seeded SBT thin films. The Avrami exponents were determined as ∼1.4 and ∼0.9 for unseeded and seeded SBT films, respectively, which reveals different nucleation modes. By using Arrhenius–type plots the activation energy values for the phase transformation of unseeded and seeded SBT thin films were determined to be ∼264 and ∼168 kJ/mol, respectively. This gives a key reason to the enhanced kinetics in seeded films. Microstructural analyses on unseeded SBT thin films showed formation of randomly oriented needle-like crystals, while those on seeded ones showed formation of domains comprised of directionally grown worm-like crystals.

Influence of nanoparticle seeding on the phase formation kinetics of sol-gel-derived Sr0.7Bi2.4Ta2O9 thin films

2003 ◽  
Vol 18 (2) ◽  
pp. 387-395 ◽  
Author(s):  
Yun-Mo Sung ◽  
Gopinathan M. Anilkumar ◽  
Seung-Joon Hwang
Keyword(s):  
Thin Films ◽  
Phase Transformation ◽  
Phase Formation ◽  
Volume Fraction ◽  
Sol Gel ◽  
Fluorite Phase ◽  
Microstructural Development ◽  
Aurivillius Phase ◽  
Si Substrates ◽  
Formation Kinetics

Sr0.7Bi2.4Ta2O9 (SBT) thin films were deposited on unseeded and SBT nanoparticle (approximately 60–80 nm) seeded Pt/Ti/SiO2Si substrates via sol-gel and spin-coating techniques. The SBT thin films were heated at 600 °C for 1 h to form the fluorite phase, and these fluorite films were further heated at 730–760 °C for fluorite-to-Aurivillius phase transformation. The volume fractions of Aurivillius phase formation obtained through quantitative x-ray diffraction analyses showed highly enhanced kinetics in seeded SBT thin films. Johnson–Mehl–Avrami isothermal kinetic analyses were performed for the characterization of Aurivillius phase formation in unseeded and seeded SBT thin films using the volume fraction values. The Avrami exponents were determined as approximately 1.4 and approximately 0.9 for unseeded and seeded SBT films, respectively, which reveals different nucleation modes. By using Arrhenius-type plots, the activation energy values for the phase transformation of unseeded and seeded SBT thin films were determined to be approximately 264 and approximately 168 kJ/mol, respectively. This gives a key reason for the enhanced kinetics in seeded films. Microstructural analyses on unseeded SBT thin films showed formation of randomly oriented needlelike crystals, while those on seeded ones showed formation of domains comprising directionally grown wormlike crystals. On the basis of the phase formation kinetics and microstructural development, a model representing different nucleation and crystal growth mechanisms for the unseeded and seeded SBT thin films was proposed.

Crystallization Kinetics of Sol-gel-derived (1x)SrBi2Ta2O9–xBi3TiTaO9 Ferroelectric Thin Films

2002 ◽  
Vol 17 (6) ◽  
pp. 1463-1468 ◽  
Author(s):  
Woo-Chul Kwak ◽  
Yun-Mo Sung
Keyword(s):  
Thin Films ◽  
Activation Energy ◽  
Crystallization Kinetics ◽  
Sol Gel ◽  
Avrami Exponent ◽  
X Ray Diffraction ◽  
X Ray ◽  
Isothermal Kinetic Analysis ◽  
Isothermal Kinetic ◽  
Kinetics Of

The crystallization kinetics of Sr0.7Bi2.3Ta2O9 (SBT) and 0.7SrBi2Ta2O9–0.3Bi3TiTaO9 (SBT-BTT) thin films formed by the sol-gel and spin coating techniques were studied. Phase formation and crystal growth are greatly affected by the film composition and crystallization temperature. Isothermal kinetic analysis was performed on the x-ray diffraction results of the thin films heated in the range of 730 to 760 °C at 10 °C intervals. Activation energy and Avrami exponent values were determined for the fluorite-to-Aurivillus phase transformation. A reduction of approximately 51 kJ/mol in activation energy was observed for the SBT-BTT thin films, and an Avrami exponent value of approximately 1.0 was obtained for both the SBT and SBT-BTT. A comparison is made, and the possible crystallization mechanism is discussed.

Crystallization of Zn-rich and P-rich amorphous Zn3P2 thin films

1988 ◽  
Vol 66 (5) ◽  
pp. 373-375 ◽  
Author(s):  
C. J. Arsenault ◽  
D. E. Brodie
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Activation Energy ◽  
Electrical Properties ◽  
Structural Properties ◽  
Crystallization Process ◽  
X Ray Diffraction ◽  
Electrical Measurements ◽  
Conductivity Activation Energy ◽  
X Ray

Zn-rich and P-rich amorphous Zn3P2 thin films were prepared by co-evaporation of the excess element during the normal Zn3P2 deposition. X-ray diffraction techniques were used to investigate the structural properties and the crystallization process. Agglomeration of the excess element within the as-made amorphous Zn3P2 thin film accounted for the structural properties observed after annealing the sample. Electrical measurements showed that excess Zn reduces the conductivity activation energy and increases the conductivity, while excess P up to 15 at.% does not alter the electrical properties significantly.

Phase Formation Kinetics in Sol-Gel Derived Strontium Bismith Tantalate

2001 ◽  
Vol 666 ◽  
Author(s):  
Yun-Mo Sung ◽  
Woo-Chul Kwack
Keyword(s):  
Activation Energy ◽  
Thermal Analysis ◽  
Phase Formation ◽  
Sol Gel ◽  
Avrami Exponent ◽  
Fluorite Phase ◽  
X Ray Diffraction ◽  
Aurivillius Phases ◽  
Formation Kinetics ◽  
Isothermal Kinetic

ABSTRACTPhase formation characteristics of Sr0.7Bi2.4Ta2O9 (SBT) powder, synthesized via sol-gel and pyrolysis process, was investigated by using thermal analysis. Each of the two exotherms, appearing in differential thermal analysis (DTA) scan curves, was identified as crystallization of fluorite phase and transformation of fluorite to aurivillius phase, respectively by using x-ray diffraction (XRD). By applying non-isothermal kinetic analyses to the DTA results, activation energy values for the formation of fluorite and aurivillius phases were determined as 192 and 375 kJ/mol, respectively and Avrami exponent values for each reaction were determined as 0.91 and 0.96, respectively. These activation energy and Avrami exponent values were discussed in detail to understand phase formation mechanism in SBT system.

A study of barium strontium titanate thin films for use in bypass capacitors

1998 ◽  
Vol 13 (1) ◽  
pp. 197-204 ◽  
Author(s):  
B. A. Baumert ◽  
L-H. Chang ◽  
A. T. Matsuda ◽  
C. J. Tracy ◽  
N. G. Cave ◽  
...  
Keyword(s):  
Thin Films ◽  
Perovskite Phase ◽  
Electrical Characterization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Barium Strontium ◽  
Aluminum Metallization ◽  
On Chip ◽  
Lower Temperature ◽  
Kinetics Of

Physical and electrical characterization techniques have been applied to the problem of developing a lower temperature process for spin-on Ba0.7Sr0.3TiO3 thin films and capacitors compatible with on-chip aluminum metallization. The films were prepared by spin-coating from carboxylate precursors and were processed at temperatures between 650 °C and 450 °C. Capacitors annealed at higher temperatures have a dielectric constant (κ) of 382, a C/A of 20 fF/μm2, and a leakage current density of 2 × 10−7 A/cm2 at 3.3 V. Those processed at 450 °C show occasionally promising but inconsistent results, correlated using TEM images with locally variable crystallization into the perovskite phase. The kinetics of the spin-on solution chemical decomposition and crystallization has been investigated through the use of x-ray diffraction (XRD), thermogravimetric analysis (TGA), and Raman spectroscopy.

An Effective Way to Suppress the Pyrochlore Phase Formation in SBT Thin Films

2003 ◽  
Vol 784 ◽  
Author(s):  
Se-Yeon Jung ◽  
Woo-Chul Kwak ◽  
Seung-Joon Hwang ◽  
Yun-Mo Sung
Keyword(s):  
Thin Films ◽  
Phase Formation ◽  
Seed Layer ◽  
Sol Gel ◽  
Pyrochlore Phase ◽  
Energy Difference ◽  
Ion Diffusion ◽  
Aurivillius Phase ◽  
Si Substrates ◽  
Coating Methods

ABSTRACTSr0.7Bi2.4Ta2O9 (SBT) thin films were deposited on Pt/Ti/SiO2/Si substrates with and without a seed layer of ∼40 nm thickness using sol-gel and spin coating methods. The influence of seed layer on the phase formation characteristics of SBT thin films was investigated using x-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses. Formation of pyrochlore as well as Aurivillius phase was observed in both the unseeded and seeded SBT films heated at 740°C. However, it was revealed that Aurivillius phase formation was enhanced in seeded SBT thin films and pyrochlore phase formation was highly suppressed. In this study, two possible mechanisms for the suppression of pyrochlore phase formation were proposed from the perspectives of activation energy difference for Aurivillius and pyrochlore phase formation and Bi-ion diffusion to pyrochlore phase.

Effects of CaF2 on the Formation Kinetics of Portland Cement Clinker

2011 ◽  
Vol 306-307 ◽  
pp. 966-969
Author(s):  
Chun Fang Wang ◽  
Zong Hui Zhou ◽  
Cai Xia Liu ◽  
Xin Cheng
Keyword(s):  
Portland Cement ◽  
Formation Rate ◽  
Reaction Rate Constant ◽  
Cement Clinker ◽  
X Ray Diffraction ◽  
Free Lime ◽  
X Ray ◽  
Formation Kinetics ◽  
Portland Cement Clinker ◽  
Kinetics Of

Through testing the amount of the free lime and the Loss ignition, the clinker formation rate, the reaction-rate constant (K) and the activation energy (Ea) were calculated according to the Gentling equation and Arrhenius equation. The effects of CaF2on the formation kinetics of Portland cement clinker were investigated by analyzing theKandEa. X-ray diffraction (XRD) and scanning electron Microscope (SEM) were used to characterize the phase composition and the morphology of the resulting samples. The results show that the silicate minerals formation is promoted when a proper amount of CaF2is doped into the raw meal. TheKincreased from 0.7450 ×10-5s-1to 7.1588 ×10-5s-1and theEadecreased from 386 kJ/mol to 122 kJ/mol when the amount of CaF2increased from 0.0% to 2.0% in mass. However, the results were reversed at the amount of CaF2exceeding 2%.

A Powder Diffractometry Study of γ'-Phase Formation

1991 ◽  
Vol 6 (2) ◽  
pp. 66-69
Author(s):  
S. Ariely ◽  
G. Kimmel ◽  
S. F. Dirnfeld ◽  
M. Bamberger ◽  
B. Prinz
Keyword(s):  
Phase Formation ◽  
Early Stage ◽  
Pure Nickel ◽  
X Ray Diffraction ◽  
Type Alloy ◽  
Optimal Program ◽  
X Ray ◽  
Nickel Base ◽  
Kinetics Of ◽  
Base Superalloy

AbstractThe kinetics of γ'-phase formation in a Ni-base superalloy were studied. The data (pairs of cps and 2θ) were processed by the deconvolution program (Wiedemann, Unnam and Clark, 1987), which was rewritten in FORTRAN and installed on an IBM/VM and a VAX/VMS host computer. Optimal program parameters were found. Pure nickel was used as a standard. The only evidence obtained from the raw data is that the early stage of the aging process is accompanied by broadening. Deconvolution resolved the peaks into three kinds of diffraction lines: Ni(γ), precipitate (γ'), and undefined lines which have been interpreted as satellites. The results show that our X-ray diffraction lines are composed of the main diffraction lines of nickel-base A1 type alloy and additive satellites. In an advanced stage of aging the satellites assume the typical diffraction pattern of γ' phase.

A Model for Formation and Consumption of Transient Phase

2011 ◽  
Vol 172-174 ◽  
pp. 646-651 ◽  
Author(s):  
Gamra Tellouche ◽  
Khalid Hoummada ◽  
Dominique Mangelinck ◽  
Ivan Blum
Keyword(s):  
Differential Scanning Calorimetry ◽  
Phase Formation ◽  
Transient Phase ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Proposed Model ◽  
Transient Phases ◽  
Kinetics Of

The phase formation sequence of Ni silicide for different thicknesses is studied by in situ X ray diffraction and differential scanning calorimetry measurements. The formation of a transient phase is observed during the formation of δ-Ni2Si; transient phases grow and disappear during the growth of another phase. A possible mechanism is proposed for the transient phase formation and consumption. It is applied to the growth and consumption of θ-Ni2Si. A good accordance is found between the proposed model and in situ measurement of the kinetics of phase formation obtained by x-ray diffraction and differential scanning calorimetry for higher thickness.

Sign in / Sign up

Export Citation Format

Share Document