Dielectric and Ferroelectric Properties of Modified BiFeO3-PbTiO3 Thin Films Derived from Sol-gel Processing

2003 ◽  
Vol 784 ◽  
Author(s):  
JinRong Cheng ◽  
L. Eric Cross

ABSTRACTIn this paper, thin films of La- modified (Bi,La)FeO3-PbTiO3 (BLF-PT) morphotropic phase boundary (MPB) solid solutions have been prepared by using sol-gel processing. A thin Pb(Zr,Ti)O3 (PZT) template layer was introduced to make BLF-PT thin films adhere tightly to the platinized silicon (Pt/Ti/SiO2/Si) substrate. X-ray diffraction (XRD) analysis revealed that BLF-PT thin films were of the perovskite structure without detectable pyrochlore phase annealing at 650–750°C. The cross sectional and plain view images of or our specimen were observed by using the scan electrical microscope (SEM). The room temperature dielectric constant K and tanδ were of ∼800 and 4% respectively, for BLF-PT thin films using a measurement frequency of 1 kHz. Our preliminary experiments indicated that the sol-gel derived BLF-PT thin films have good insulation resistance and measurable dielectric and ferroelectric responses.

1997 ◽  
Vol 12 (6) ◽  
pp. 1441-1444 ◽  
Author(s):  
L. Armelao ◽  
A. Armigliato ◽  
R. Bozio ◽  
P. Colombo

The microstructure of Fe2O3 sol-gel thin films, obtained from Fe(OCH2CH3)3, was investigated by x-ray diffraction (XRD), transmission electron microscopy (TEM), and Raman spectroscopy. Samples were nanocrystalline from 400 °C to 1000 °C, and the crystallized phase was haematite. In the coatings, the α–Fe2O3 clusters were dispersed as single particles in a network of amorphous ferric oxide.


2012 ◽  
Vol 557-559 ◽  
pp. 1933-1936
Author(s):  
Ning Yan ◽  
Sheng Hong Yang ◽  
Yue Li Zhang

Pure BiFeO3(BFO) and Bi0.9Nd0.1Fe0.925Mn0.075O3(BNFM) thin films were deposited on Pt(111)/Ti/SiO2/Si substrate by sol-gel method. X-ray diffraction analysis showed that all the films were single perovskite structure and a phase transition appeared in Nd–Mn codoped BiFeO3 thin films. Electrical measurements indicated that the ferroelectric properties of BFO thin films were significantly improved by Nd and Mn codoping. BNFM films exhibit a low leakage current and a good P-E hysteresis loop. The remanent polarization (Pr) value of 74μC/cm2has been obtained in BNFM films, while the coercive field (Ec) is 184kV/cm.


2016 ◽  
Vol 697 ◽  
pp. 288-292
Author(s):  
Xin Xu ◽  
Qi Fu Yao ◽  
Sheng Peng ◽  
Long Kai Fang ◽  
Wei Wei Mao ◽  
...  

Pure BiFeO3 (BFO), Ca-doped and Eu/Ca-codoped BFO nanoparticles were prepared by using a sol–gel method. The effects of Eu/Ca-codoped on the structural, magnetic and ferroelectric properties of the samples were studied. The X-ray diffraction (XRD) analysis reveals a structure transition in the codoped samples. Co-doped samples were obtained with the best ferromagnetic properties, with the largest remaining magnetization Mr = 0.20 emμ/g. The structure transition may be the main cause for the origin of improved magnetic properties, which destroys the space modulated spin structure of BFO and releases the locked magnetic. In addition, the doping of Eu into BFO can reduce the leakage current and enhance the ferroelectric properties.


Author(s):  
M. C. Gust ◽  
N. D. Evans ◽  
M. L. Mecartney

Sol-gel processing of oxide thin films offers the potential to generate different microstructures by varying process parameters such as water of hydrolysis, chemical precursor, or substrate. For this work, barium titanate (BaTiO3) thin films were prepared by the sol-gel method in order to try and generate different microstructures for dielectric measurements. However, for BaTiOs prepared using alkoxide precursors, the final microstructures of the films were found to be almost process independent. Films using different precursors, different substrates, and different amounts of water of hydrolysis all showed similar TEM microstructures. All the films after final heat treatment were polycrystalline, nanoporous, and randomly oriented BaTiO3; they were also fine-grained, with an average uniform grain size of 25-50 nm (Fig. 1). This fine-grained microstructure has also been observed in other studies of sol-gel derived BaTiO3 thin films. In addition to BaTiO3, electron diffraction patterns showed the presence of trace amounts of rutile TiO2 that were not observed by x-ray diffraction (XRD).


2015 ◽  
Vol 1109 ◽  
pp. 181-185 ◽  
Author(s):  
Mohd Firdaus Malek ◽  
Mohamad Hafiz Mamat ◽  
M.Z. Musa ◽  
M. Rusop

Multilayered thin films of aluminum-doped ZnO (Al:ZnO) have been deposited by the sol-gel dip coating technique. Experimental results indicated that the thermal annealing temperature affected the crystallinity of the Al:ZnO films. X-ray diffraction (XRD) analysis showed that thin films were preferentially orientated along the c-axis plane. The preferred orientation along (0 0 2) plane becomes more pronounced as the thermal annealing being increased. The film thickness ranges between 180 and 690 nm. In our experiments, the most optimum condition of Al:ZnO annealing temperature was both 500 oC.


2012 ◽  
Vol 512-515 ◽  
pp. 1317-1320
Author(s):  
Fann Wei Yang ◽  
Kai Huang Chen ◽  
Chien Min Cheng

We have investigated the structure and ferroelectric properties of the Bi3.25La0.75Ti3O12 (BLT) thin films on SiO2/Si substrate fabricated by sol-gel method. We used the BLT films were annealed at various temperatures of 600, 650, and 700°C for one hour by conventional furnace annealing (CTA). The temperature dependence of leakage currents densities of ferroelectric BLT thin films. The crystalline structure of the prepared BLT thin films was analyzed by X-ray diffraction (XRD). Field emission scanning electron microscopy (FESEM) was used to observe the film thickness and the surface morphology including grain size and porosity. The leakage current density and capacitance of thin film were measured by HP4156C.


2011 ◽  
Vol 287-290 ◽  
pp. 2318-2321
Author(s):  
Shu Lan Guo ◽  
Jia Li ◽  
Xue Dong Xu

Ferroelectric thin films Bi3.25La0.75Ti3O12,Bi3.15Nd0.85Ti3O12 and Bi3.15(La0.5Nd0.5)0.85Ti3O12 of A-site substitution of Bi4Ti3O12 were fabricated by sol-gel method in the paper. X-ray diffraction pattern shows the prepared thin films exhibit a highly random orientation with predominantly (117) and (00l) orientation. Pr values of Bi3.25La0.75Ti3O12 、Bi3.15Nd0.85Ti3O12 and Bi3.15(La0.5Nd0.5)0.85Ti3O12 thin films were respectively 13.14μC/cm2, 20.65μC/cm2 and 21.23μC/cm2 at the voltage of 10V.FE-SEM shows that the BNT thin film has a dense and homogeneous microstructure without any crack. The BNT thin film thickness is about 300nm.


2020 ◽  
Vol 11 (1) ◽  
pp. 123-131
Author(s):  
Nushrat Naushin ◽  
Sadi Md Shahriar ◽  
Oishy Roy ◽  
Ahmed Sharif

The structural, morphological, magnetic and ferroelectric properties of calcium (Ca) doped bismuth ferrite (BFO) synthesized using a sol-gel method were studied. X-ray diffraction (XRD) analysis followed by Rietveld refinement revealed the lattice distortion of BFO after doping with 6% and 8% Ca. This also led to the reduction in particle size by creating oxygen vacancies, which was observed from the surface morphology using Field Emission Scanning Electron Microscopy (FESEM). The Magnetic properties exhibited some enhancements in saturation magnetization when the particle size was near a limiting value. The reduction in the coercive magnetic field with the increase in dopant concentration was also evident from the M-H hysteresis loop measured by Vibrating Sample Magnetometer (VSM). The Ferroelectric P-E hysteresis loop exhibited an increased symmetry in the hysteresis loop and increase in the polarization with the increase in %Ca. The 8% Ca doped BFO exhibited an incomplete saturation in the hysteresis loop and was evident to exhibit leakage current characteristics. Journal of Engineering Science 11(1), 2020, 123-131


2019 ◽  
Vol 37 (2) ◽  
pp. 190-195 ◽  
Author(s):  
Denis Sokol ◽  
Maksim Ivanov ◽  
Andrei N. Salak ◽  
Robertas Grigalaitis ◽  
Juras Banys ◽  
...  

AbstractMagnesium-aluminum-bismuth layered double hydroxides (Mg3Al1−xBix; LDHs) were prepared using both coprecipitation and sol-gel methods. For the preparation of Mg/Al/Bi LDH by the co-precipitation method, the appropriate amounts of dissolved starting materials (Al(NO3)3 · 9H2O, Mg(NO3)2 · 6H2O and Bi(NO3)3 · 5H2O) were mixed with a solution of NaHCO3:NaOH. In the sol-gel processing, the precursor Mg–Al–Bi–O gels were synthesized using the same starting materials and ethylene glycol as complexing agent. The mixed-metal oxides obtained by subsequent heating of Mg–Al–Bi–O gels at 650 °C were reconstructed to Mg3Al1−xBix LDHs in water at 80 °C. All the synthesized products were characterized by X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM) and dielectric measurements.


1998 ◽  
Vol 541 ◽  
Author(s):  
Chung-Hsin Lu ◽  
Cheng-Yen Wen

AbstractSrBi2Ta2O9thin films doped with barium ions were studied, in which Ba/(Sr+Ba) = 0.3 and 0.5, meanwhile the content of (Sr+Ba) remains unity to keep the stoichiometry of SrBi2Ta2O9. Films were deposited using metalorganic decomposition method with spin-on coating. Crystallinity, surface morphology, and ferroelectric properties of prepared thin films were investigated. From X-ray diffraction (XRD) analysis, barium ions substituted strontium ions in the SrBi2Ta2O9 lattice. Shift of diffraction peaks was observed, indicating a slight distortion of the lattice while barium ions incorporated into. The observation of prepared films indicated that the grain size of films annealed at 750 °C was about 0.7∼0.8 μm. Such barium incorporated SrBi2Ta2O9 thin films exhibited higher remanent polarization than the intrinsic SrBi2Ta2O9thin films.


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