Structural and Ferroelectric Properties of Bi4-xNixTi3O12 Thin Films by Sol-Gel Process

2006 ◽  
Vol 966 ◽  
Author(s):  
Ricardo Melgarejo ◽  
Maharaj S Tomar ◽  
Rahul Singhal ◽  
Ram S Katiyar
Keyword(s):  
Thin Films ◽  
Ferroelectric Properties ◽  
Sol Gel ◽  
Low Frequency ◽  
X Ray Diffraction ◽  
Coating Materials ◽  
Low Field ◽  
Sol Gel Process ◽  
Raman Modes ◽  
Ferroelectric Memories

ABSTRACTNickel-substituted Bi4Ti3O12 (i.e., Bi4-xNixTi3O12) were synthesized by sol-gel process for different compositions. Thin films were deposited on Pt (i.e., Pt/TiO2/SiO2/Si) substrate by spin coating. Materials were characterized by x-ray diffraction and Raman spectroscopy. This study indicates that the material makes a solid solution for the compositions: x = 0.00, 0.05, 0.10, 0.15, 0.20, and 0.30, where a Ni ion replaces the Bi site. The prominent effect of Ni substitution was observed in low-frequency Raman modes. Sol-gel derived thin films of Bi4-xNixTi3O12 on a Pt substrate and post annealed at 700°C were tested for ferroelectric response which showed high remnant polarization (Pr = 22 μC/cm2 for x = 0.15). The leakage current (less then 10−7 A/cm2) at low field was observed in the film with composition x = 0.15 .The polarization of the BNiT (x = 0.15) film decreased to 83% of the initial value after 1×109 switching cycles These results indicate the potential application of Ni substituted bismuth titanate films in non-volatile ferroelectric memories.

Effect of Cationic Substitution on Raman Spectra of SrBi2Ta2O9Ceramics and Thin Films

2003 ◽  
Vol 784 ◽  
Author(s):  
W. Perez ◽  
R. R. Das ◽  
P. S. Dobal ◽  
Y. I. Yuzyuk ◽  
P. Bhattacharya ◽  
...  
Keyword(s):  
Thin Films ◽  
Transition Temperature ◽  
Lattice Mismatch ◽  
Ferroelectric Properties ◽  
Low Frequency ◽  
X Ray Diffraction ◽  
Ionic Radii ◽  
Cationic Substitution ◽  
Factor Substitution ◽  
Raman Modes

ABSTRACTIn the present work micro-Raman spectroscopy has been used to understand the lattice dynamics of cation substituted SBT ceramics and thin films. Different concentrations of Ca and V were introduced into SBT lattices. Incorporation of Ca ion at Sr-site was confirmed by decrease in the lattice parameters calculated from x-ray diffraction data. The lowest Raman modes at 27 cm-1and 58 cm-1showed upward shift with increasing Ca concentration and was attributed to the lower mass and lower ionic radii of Ca. The temperature dependant Raman studies revealed the increase of the phase transition temperature with increased Ca content, and was attributed to the decrease in tolerance factor. Substitution of smaller cation at Sr site in SBT compound has increased lattice mismatch between SrO and TaO2planes inside the stable perovskite unit of SrTa2O7which has pronounced influence on ferroelectric properties of SBT. Substitution of vanadium at Ta-site of SBT did not influence the low frequency Raman modes of SBT. However, it showed a pronounced influence on the O-Ta-O stretching modes by splitting the mode frequency at 810 cm-1. The transition temperature of SBT was reduced with increasing vanadium contents.

Ferroelectric memory in La substituted Bi4Ti3O12 thin films

2003 ◽  
Vol 784 ◽  
Author(s):  
R. E. Melgarejo ◽  
M. S. Tomar
Keyword(s):  
Thin Films ◽  
Film Growth ◽  
Sol Gel ◽  
Low Frequency ◽  
X Ray Diffraction ◽  
X Ray ◽  
Raman Modes ◽  
La Substitution ◽  
Ferroelectric Memory ◽  
Recent Demonstration

ABSTRACTThe recent demonstration of large ferroelectric memory in rare earth substituted Bi4Ti3O12 attracted a lot of research interest in this material. Bi4-xLaxTi3O12 was synthesized by sol-gel route for different compositions: x = 0.00, 0.46, 0.56, 0.75, 0.95 and thin films were deposited by spin coating on Pt (Pt/TiO2/SiO2/Si) substrate. The post annealed films at 700°C were studied for their structural studies using x-ray diffraction and Raman spectroscopy. The prominent effect of La substitution is observed in low frequency Raman modes. X-ray diffraction and Raman studies show that the film growth was c-axis suppressed. Using improved contacts to Pt substrate, ferroelectric polarization Pr = 51 μC/cm2 has been achieved for 0.63 μm thick film of composition: x = 0.56 (BLT56) without appreciable fatigue.

Effect of Bottom Electrodes on Structural and Electrical Properties of Laser Ablated SrBi2Ta2O9 Thin Films

2001 ◽  
Vol 688 ◽  
Author(s):  
Rasmi R. Das ◽  
W. Pérez ◽  
P. Bhattacharya ◽  
Ram. S. Katiyar
Keyword(s):  
Thin Films ◽  
Barrier Height ◽  
Ferroelectric Properties ◽  
High Resistivity ◽  
Emission Model ◽  
X Ray Diffraction ◽  
Oxide Electrodes ◽  
Maximum Value ◽  
Structural And Electrical Properties ◽  
Raman Modes

AbstractWe have grown SrBi2Ta2O9 (SBT) thin films on various bottom electrodes such as Pt/TiO2/SiO2/Si (Pt) and LaNiO3/Pt/TiO2/SiO2/Si (LNO) substrates. The substrate temperature and oxygen pressure for the SBT film was maintained at 500 °C and 200 mTorr. As-grown films were post-annealed at a temperature of 800 °C. X-ray diffraction studies revealed that as-grown films were amorphous and crystallized to single phase after annealing. The difficulty of obtaining lowest Raman modes of SBT on platinized silicon substrate was overcome by using conducting oxide electrodes. Films grown on platinized silicon showed maximum value of remanent polarization (2Pr ∼ 21.5 μC/cm2) with coercive field (Ec) of ∼ 67 kV/cm. The degradation of ferroelectric properties of the films was observed with the introduction of 50 nm conducting LaNiO3 electrode at the interface of Pt and SBT film, which was attributed to high resistivity of the oxide electrode layers. Leakage current density was studied with the consideration of the Schottky emission model. The barrier height of the films grown on Pt and LNO were estimated to be 1.27 eV and 1.12 eV, respectively. The reduction of barrier height was attributed to the lower work function of the LNO electrode.

Sol-Gel derived Bi4-xNdxTi3O12 Thin Films and Their Characterization

2002 ◽  
Vol 737 ◽  
Author(s):  
R.E. Melgarejo ◽  
M.S. Tomar ◽  
A. Hidalgo ◽  
R.S. Katiyar
Keyword(s):  
Thin Films ◽  
Spin Coating ◽  
Bismuth Titanate ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Complete Solid Solution ◽  
Sol Gel Process ◽  
Ferroelectric Memory ◽  
Initial Results

ABSTRACTNd substituted bismuth titanate Bi4-xNdxTi3O12 were synthesized by sol-gel process and thin films were deposited on Pt substrate (Pt/TiO2/SiO2/Si) by spin coating. Thin films, characterized by X-ray diffraction and Raman spectroscopy, shows complete solid solution up to the composition x < 1. Initial results indicate that the ferroelectric polarization increases with increasing Nd content in the film with 2Pr = 50μC/cm2 for x = 0.46, which may have application in non-volatile ferroelectric memory devices.

Synthesis and Characterizations of Strontium Substituted Hydroxyapatite Thin Films

2010 ◽  
Vol 93-94 ◽  
pp. 231-234
Author(s):  
B. Hongthong ◽  
Satreerat K. Hodak ◽  
Sukkaneste Tungasmita
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Chemical Composition ◽  
Spin Coating ◽  
Phase Structure ◽  
Sol Gel ◽  
Cross Linking ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sol Gel Process

Strontium substituted hydroxyapatite(SrHAp) were fabricated both in the form of powder as reference and thin film by using inorganic precursor reaction. The sol-gel process has been used for the deposition of SrHAp layer on stainless steal 316L substrate by spin coating technique, after that the films were annealed in air at various temperatures. The chemical composition of SrHAp is represented (SrxCa1-x)5(PO4)3OH, where x is equal to 0, 0.5 and 1.0. Investigations of the phase structure of SrHAp were carried out by using X-ray diffraction technique (XRD). The results showed that strontium is incorporated into hydroxyapatite where its substitution for calcium increases in the lattice parameters, and Sr3(PO4)2 can be detected at 900°C. The SEM micrographs showed that SrHAp films exhibited porous structure before develop to a cross-linking structure.

Characterisation of Ferroelectric Lithium Tantalate Thin Films Prepared by a Sol-Gel Process

1993 ◽  
Vol 321 ◽  
Author(s):  
Chianping Ye ◽  
Paul Baude ◽  
Dennis L. Polla
Keyword(s):  
Thin Films ◽  
Curie Temperature ◽  
Single Crystal ◽  
Silicon Substrate ◽  
Ferroelectric Properties ◽  
Sol Gel ◽  
Precursor Solution ◽  
Pyroelectric Coefficient ◽  
Crystal Silicon ◽  
Sol Gel Process

ABSTRACTThin LiTaO3 films were prepared by spin coating of polymerized sol-gel precursor solution. Films have been deposited on single crystal silicon substrate, Ti/Pt or SiO2 coated silicon substrate. Films were characterized by x-ray diffraction, dielectric and pyroelectric Measurements. High Curie temperature (above 550 °C) was assumed for LiTaO3 thin films from the temperature dependence of dielectric constant. Replacing 35% of tantalum by titanium atoms in the LiTaO3 precursor solution has resulted the thin films with Curie temperature of 330 °C. The lower Curie temperature leads to the larger pyroelectric coefficient at room-temperature, which is more than double that of the undoped LiTaO3 thin films. The dielectric, pyroelectric, and ferroelectric properties have been compared to the single crystal LiTaO3 and ceramic Li0.91Ta0.73Ti0.36O3. LiTaO3 thin films are available by sol-gel process at low temperature, and their properties may possibly be controlled by varying the composition of the sol-gel precursor solution.

Barium Titanate Ceramic/Ceramic 0–3 Composites for Ultrasonic Transducer Applications

1999 ◽  
Vol 574 ◽  
Author(s):  
M. C. Cheung ◽  
H. L. W. Chan ◽  
Q. F. Zhou ◽  
C. L. Choy
Keyword(s):  
Barium Titanate ◽  
Ceramic Composite ◽  
Ultrasonic Transducer ◽  
Ferroelectric Properties ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Barium Titanate Ceramic ◽  
Sol Gel Process ◽  
Titanate Ceramic

AbstractBarium titanate (BaTiO3) 0–3 ceramic/ceramic composite thick films (∼16μm) for ultrasonic transducer applications were fabricated by a modified sol-gel process. Nano-sized BaTiO3 powder was dispersed in a sol-gel matrix of BaTiO3 to form a 0–3 composite solution. Films were prepared by spin coating and then annealed at various temperatures. The crystallization of the composite film was studied by X-ray diffraction. The dielectric permittivity and the ferroelectric properties of the film were also measured.

Structural and Vibrational Properties of Ferroelectric Pb1-xSrxTiO3 Thin Films and Powders

2002 ◽  
Vol 748 ◽  
Author(s):  
M. Jain ◽  
A. Savvinov ◽  
P. S. Dobal ◽  
S. B. Majumder ◽  
R. S. Katiyar ◽  
...  
Keyword(s):  
Thin Films ◽  
Soft Mode ◽  
Ferroelectric Properties ◽  
Sol Gel ◽  
Vibrational Properties ◽  
X Ray Diffraction ◽  
Phase Transition Temperatures ◽  
Induced Changes ◽  
Pst System

ABSTRACTIn this work we present the structural, and vibrational properties of ferroelectric Pb1-xSrxTiO3 (PST). Thin films of PST were prepared by using sol-gel technique for various compositions with x values ranging from 0.0–1.0. Respective compositions were also prepared in ceramic and powder forms using sol-gel and solid-state reaction methods. X-ray diffraction was used for the structural characterization of these materials. Raman spectroscopy was utilized to study the phases and lattice vibrational modes, especially the soft mode in PST compositions. The temperature dependence of the soft mode frequency for different PST compositions revealed that the phase transition temperatures increased with increasing Pb contents in PST system. Ferroelectric properties of the films were correlated with the substitution-induced changes in the material.

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