Preparation and Characterization of Relaxor-Based Ferroelectric Thick Films with Single Perovskite Structure

2008 ◽  
Vol 368-372 ◽  
pp. 24-26 ◽  
Author(s):  
Hui Qing Fan ◽  
Jin Chen ◽  
Xiu Li Chen

Lead magnesium niobate-lead titanate (0.8Pb(Mg1/3Nb2/3)O3-0.2PbTiO3, PMN-PT) thick films in the thickness range about 75 μm have been successfully fabricated on Au-coated Al2O3 substrates by electrophoretic deposition (EPD). Non-aqueous colloidal suspensions suitable for EPD were prepared by mixing ultrasonically PMN-PT particles in ethanol with pH=6.0. The effect of EPD process parameters such as deposition voltage, deposition time and the specific deposition mass of PMN-PT particles were investigated. The EPD parameters were optimized in order to obtain crack-free, high-quality uniform ceramic films. The deposited pyrochlore-free PMN-PT thick films were sintered at 1000oC for 30 min, and the phase evolvement and the microstructure of the film were characterized by X-ray diffraction and scanning electron microscope.

2002 ◽  
Vol 743 ◽  
Author(s):  
Minseo Park ◽  
E. Carlson ◽  
Y. C Chang ◽  
J. F. Muth ◽  
J. Bumgarner ◽  
...  

ABSTRACTThe thick films of GaN were investigated using X-ray diffraction, micro-Raman spectroscopy and photoluminescence spectroscopy. The thick films of GaN were prepared on (0001) sapphire using high rate magnetron sputter epitaxy with growth rates as high as 10–60 m/min. The width of the X-ray rocking curve ((0002) reflection) for the sample produced by this method is ∼300 arc-sec. Only the allowed modes were observed in the polarized Raman spectra. The background electron concentration is lower than 3×1016 cm−3, which was determined from the Raman spectra. The phonon lifetime determined from Raman E2(2) mode was 1.6 ps, which is comparable to that of bulk single crystal GaN grown by sublimation (1.4 ps). The full-width-at-half-maximum of the near band-edge photoluminescence peak obtained at 77K is ∼100 meV.


2000 ◽  
Author(s):  
Jin T. Wang ◽  
Feng Tang

Abstract Ta-Doping effect on the microstructure of lead magnesium niobate-lead titanate crystalline solutions 0.9PbMg1/3(Nb(1−x)Tax)2/3O3-0.1PbTiO3(PMN-PT) have been firstly investigated in this paper. Scanning Electron Micrographs (SEM) were taken from fractured surfaces of the samples with different additives of x = 0.0, 0.1, 0.2, 0.3 and 1.0 by Hitachi F-2460N microscope operating at an accelerating voltage of 25kV. The chemical content analysis for the synthesized samples performed on JEOL Super Prob733 Energy Perspective Spectrum. The x-ray diffraction was carried out with a Siemens D5000 Dual Diffraction Meter. It is clearly evident that doping Ta in PMNTa-PT can affect the grain size and density of the compounds. Smaller grain size (3.1μm) is formed in the specimens with the additives of x = 0.1, 0.2 and 0.3 in comparison with those of the specimens without doping (6.6μm) or over doping (6.4μm). The porosity at grain intersections increase with increasing of additive tantalum for niobium site in 0.9PMNTa-0.1PT. Larger grain size (6.4μm), greater non-uniformity and more inter-granular voids are found in the compound, if tantalum completely substitutes niobium (x = 1). No non-reacted starting regents were observed in any of the compositions mentioned above.


2012 ◽  
Vol 620 ◽  
pp. 435-439 ◽  
Author(s):  
Wan Fahmin Faiz Wan Ali ◽  
Mohamad Ariff Othman ◽  
Nik Akmar Rejab ◽  
Mohd Zaid Abdullah ◽  
Arjuna Marzuki ◽  
...  

This manuscript is explained and discussed the properties of ceramic thick films, [Ba0.3Sr0.7ZrO3,BSZ (0.7)] synthesized through sol-gel route. The gel decomposition was studied by thermogravinometry analysis (TGA). From thermal analysis, it had shown that BSZ (0.7) phase started formed at 800 °C and above. The crystal structure of this composite film studied exhibited highly polycrystalline materials by X-ray diffraction analysis. From high magnification observation of field emission scanning electron microscopy (FESEM), grain boundaries of BSZ (0.7) films are clearly defined meanwhile grains displayed are in flaky shape. The average diameters of the grains measured were 94.6 nm. However, grains boundaries of BSZ (0.0) films, are unclear and grains slightly look dendritic structure. Electrical characterizations of the films are carried out with impedance analyzer at 4 - 12 GHz respectively. Both of electrical permittivity and loss tangent observed are dependable with microstructural and structural of the films.


2011 ◽  
Vol 194-196 ◽  
pp. 2046-2049
Author(s):  
Laongnuan Srisombat ◽  
Rewadee Wongmaneerung ◽  
Rattikorn Yimnirun ◽  
Supon Ananta

Perovskite relaxor ferroelectric PMN ceramics, Pb (Mg1/3Nb2/3O3), have been fabricated using a two-stage process employing a corundum-type Mg4Nb2O9 as a key precursor. The 100% perovskite PMN ceramics was revealed by X-ray diffraction analysis. The SEM image of the PMN ceramic shows irregular shape PMN grains on the porous surface. The surface chemical composition of the PMN ceramics could be characterized by X-ray photoelectron microscopy technique. The XPS results indicate most of the elements consist of more than one chemical species. The important of XPS studies here can reveal small amount of species which could not detected by XRD.


2010 ◽  
Vol 93-94 ◽  
pp. 340-343 ◽  
Author(s):  
Adisorn Buranawong ◽  
Surasing Chaiyakhun ◽  
Pichet Limsuwan

Nanocrystalline aluminium titanium nitride (AlTi3N) thin films were deposited on Si (100) wafers and grids by reactive magnetron co-sputtering technique using titanium and aluminium targets. The films were sputtered in Ar and N2 mixture at a constant flow rate under different conditions of deposition time ranging from 15 to 60 minutes. The crystal structure was characterized by X-Ray diffraction (XRD) and microstructure was analyzed by transmission electron microscopy (TEM). The results indicated that the formation of polycrystalline AlTi3N with the orthorhombic structure and the development of crystal structure was observed by varied the deposition time. The microstructure of films was good according to the XRD results. On the other hand, after annealed the films at 500OC in the air for 1 hour, the crystal structure did not change that exposed the stable structure of AlTi3N films.


2010 ◽  
Vol 129-131 ◽  
pp. 1201-1205 ◽  
Author(s):  
Hai Li Yang ◽  
Ai Min Gao ◽  
Yu Zhu Zhang ◽  
Yun Gang Li ◽  
Guo Zhang Tang ◽  
...  

Fe3Si layer was prepared by pulse eletrodeposition of Si on the surface of non-oriented steel in molten salts. With an orthogonal test the optimal process parameters were determined: the formulation of salts was NaCl:KCl:NaF:SiO2=1:1:3:0.3(mole ratio), current density of 60 mA/ cm2, duty cycle of 30%, pulse period of 1000 s and a deposition time of 50 min, respectively. The compositional depth profile, the structure, the surface morphology and cross sectional micrograph of the layer were studied by glow discharge spectrometry (GDS), X ray diffraction (XRD), scanning electron microscopy (SEM) and optical microscope (OM). The results showed that Si in the layer existed in the form of the gradient distribution. The phase structure of the layer was composed of the single-phase Fe3Si. The layer composed of equiaxed grains. The surface appeared smooth and dense, and with uniform thickness.


1996 ◽  
Vol 97 (8) ◽  
pp. 693-698 ◽  
Author(s):  
Q.M Zhang ◽  
Hoydoo You ◽  
Maureen L Mulvihill ◽  
S.J Jang

Author(s):  
Ashok Bhakar ◽  
Adityanarayan H. Pandey ◽  
M. N. Singh ◽  
Anuj Upadhyay ◽  
A. K. Sinha ◽  
...  

The room-temperature synchrotron powder X-ray diffraction pattern of the single phase perovskite lead magnesium niobate (PMN) has shown significant broadening in theqrange ∼ 5–7 Å−1compared with standard LaB6synchrotron powder X-ray diffraction data, taken under similar conditions. This broadening/asymmetry lies mainly towards the lower 2θ side of the Bragg peaks. Attempts to fit this data with the paraelectric cubic phase (Pm\bar 3m) and the local rhombohedral phase (R3m) corresponding to polar nanoregions (PNRs) are made using the Rietveld method. Rietveld refinements show that neither cubic (Pm\bar 3m) nor rhombohedral (R3m) symmetry can fit this XRD pattern satisfactorily. The two-phase refinement fits the experimental data satisfactorily and suggests that the weight percentage of the PNRs is approximately 12–16% at room temperature. The unit-cell volume of these rhombohedral PNRs is approximately 0.15% larger than that of the unit cell volume of the paraelectric cubic phase.


1992 ◽  
Vol 285 ◽  
Author(s):  
J.S. Horwitz ◽  
D.B. Chrisey ◽  
K.S. Grabowski ◽  
C.A. Carosella ◽  
P. Lubitz ◽  
...  

ABSTRACTHigh quality, epitaxial barium hexaferrite (BaFe12O19) thin films have been deposited by pulsed laser deposition (PLD) onto basal plane sapphire at substrate temperatures of 900°C in 400 mTorr of oxygen. Thin films (< 500 nm) were smooth while thick films (> 1000 nm) had rough, polycrystalline surfaces and “soot-like” appearances. The integration of ferrite films with semiconductors will require thick films (< 70 μm) and low substrate processing temperatures (≤ 600°C). Films deposited at 600°C were mostly amorphous with the presence of some crystalline, non-hexaferrite material. In an effort to improve the quality of barium hexaferrite fihns, we have investigated the effects of excimer-laser-assisted PLD (LAPLD) on the growth of BaFe12O19. During the deposition, the substrate was illuminated with the output of a second pulsed excimer laser (KrF) weakly focused to an energy of 10 to 130 mJ/cm2. The output of the second laser was synchronized such that the delay between the vaporization laser and the annealing laser was 0 to 1 ms. The X-ray diffraction analysis of LAPLD films deposited at 600°C with an annealing fluence of 50 mJ/cm2 indicated that the films were a crystalline mixture of hexaferrite and non-hexaferrite phases. Both phases exhibited a preferred orientation characterized by narrow x-ray rocking curve widths (FWHM ∼ 1°). Magnetic properties (magnetic moment, saturation magnetization and coercive field) detennined from a vibrating sample magnetometer (VSM) also confirmed the presence of oriented hexaferrite material in the laser annealed samples. These results show clear advantages of LAPLD for improved structural and magnetic properties of BaFe12O19 deposited at substrate temperatures compatible with semiconducting materials.


2010 ◽  
Vol 654-656 ◽  
pp. 1978-1981
Author(s):  
Hui Qing Fan ◽  
Zhuo Li ◽  
Peng Rong Ren ◽  
Gang Cheng Jiao

The new electrostrictive ceramics have been produced from the (1-x) K0.5Na0.5NbO3-xSrTiO3 (KNN-ST, x=0.1-0.25) system by using conventional mixed-oxide methods. Sintering temperatures rise with increasing SrTiO3 content (x=0.1-0.25) and are in a very narrow range. The x-ray diffraction patterns indicate that with the increasing of SrTiO3 up to 0.25, KNN-ST ceramics with a single perovskite structure exhibit a transition from orthorhombic to cubic and no other impure phase appeared. The dielectric and relaxor ferroelectric properties of KNN-ST ceramics are investigated with the different SrTiO3 content. Also, the strain of these ceramics induced by applied electric fields have been studied. The electrostrictive response is similarly as in the classical PMN (lead magnesium niobate), but lower (order of the 10-5) than PMN (order of the 10-3). Furthermore, this system shows translucent, high dielectric constant, thus suggests possible applications in electric-optic devices, electromechanical transducer applications.


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