Microstructural Correlation with Electrical Properties for Y2O3 Doped CeO2 Thin Films

1997 ◽  
Vol 500 ◽  
Author(s):  
Chunyan Tian ◽  
Siu-Wai Chan
Keyword(s):  
Electrical Properties ◽  
Grain Boundary ◽  
Complex Impedance ◽  
Fused Silica ◽  
X Ray Diffraction ◽  
Spectroscopy Analysis ◽  
Boundary Conductivity ◽  
Bulk Ceramic ◽  
Transmission Electron ◽  
Beam Deposition

ABSTRACTHigh quality textured 0.58% Y2O3 doped CeO2 films with (001), (111)/(001) and (110) were prepared using an e-beam deposition technique on substrates of (001) LaAlO3, r-cut sapphire, and fused silica, respectively. The composition and stoichiometry of the films were verified by Rutherford backscattering spectroscopy analysis. Both x-ray diffraction and transmission electron microscopy analyses gave consistent microstructural information. Complex impedance measurements have been performed to study the electrical properties of these films as a function of temperature. The conductivities of the films were dominated by grain boundaries of high conductivities as compared to that of the bulk ceramic of the same dopant concentration. The activation energies for the film conductivities were only slightly higher than that for the bulk lattice conductivities, but much lower than that for the bulk grain boundary conductivity. These results have been discussed in terms of the differences of the grain size and grain boundary microstructures between the films and the bulk ceramics.

Grain boundary conductivity and microstructure study of 4% Y2O3 doped CeO2 thin films

1996 ◽  
Vol 453 ◽  
Author(s):  
Chunyan Tian ◽  
Siu-Wai Chan
Keyword(s):  
Thin Films ◽  
Grain Boundary ◽  
Complex Impedance ◽  
Preexponential Factor ◽  
X Ray Diffraction ◽  
Ac Impedance Spectroscopy ◽  
Boundary Conductivity ◽  
Transmission Electron ◽  
Brick Layer Model ◽  
Beam Deposition

AbstractThe thin films of 4% Y2O3 doped CeO2 have been deposited on different substrates of Pd film/(001) LaAlO3, Pd film/r-cut sapphire, and Pd film/Quartz using an e-beam deposition technique. The microstructures and electrical properties of the films were investigated by means of x-ray diffraction, transmission electron microscopy, and ac impedance spectroscopy. Both textured and polycrystalline films were produced on different substrates. A brick layer model was adopted to correlate the micro structure and electrical property of the films. Only the grain boundary arc was observed in the film complex impedance plots. The conductivities of the films were similar to the conductivity of 6% Y2O3 doped CeO2 bulk grain boundary because of lower preexponential factor, although the activation energies were smaller than that of bulk grain boundary. The resistive gram boundaries were found to dominate the conductivities of the films.

Impedance Spectroscopy Analysis of p Type Li Doped ZnO Thin Film Effect

2011 ◽  
Vol 415-417 ◽  
pp. 1925-1932 ◽  
Author(s):  
Kuo Chuang Chiu ◽  
Yu Han Wu
Keyword(s):  
Thin Film ◽  
Impedance Spectroscopy ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Complex Impedance ◽  
Spectroscopy Analysis ◽  
Boundary Conductivity ◽  
Impedance Spectroscopy Technique ◽  
P Type ◽  
Li Content

Impedance spectroscopy technique was employed to characterize the LixZn1-xO2 (x=0.001~0.008) polycrystalline thin film. IS is shown to be an efficient method capable of detecting the contributions of the resistances of grains and grain boundaries resistance to the complex impedance of a compound, accurately estimating its electrical conductivity as well as its corresponding activation energies and conclude on its structural properties. This is demonstrated for the case of lithium segregation in the grain/grain boundary of LixZn1-xO2., we found that the activation energy decrease associated with grain-boundary conductivity reflects the onset of the segregation of excessive Li in the grain boundaries when the Li-content exceeds 0.5 mol%. For Li-content below 0.5mol% is the detection of a transition from p-type conductivity. It might be due to that the Li+ doped mainly in grains and no precipitation observed on the grain boundaries. So we could be process stable p type thin film for Li content below 0.5mol%.

Ionic Conductivities of Doped CeO2 Thin Films as Related to Their Microstructure

1995 ◽  
Vol 411 ◽  
Author(s):  
Chunyan Tian ◽  
Siu-Wai Chan
Keyword(s):  
Thin Films ◽  
Electrical Properties ◽  
Ionic Conductivities ◽  
Dielectric Constants ◽  
Grain Structure ◽  
X Ray Diffraction ◽  
Fine Grain ◽  
Brick Layer Model ◽  
Columnar Grain ◽  
Beam Deposition

ABSTRACTThin films of 4% Y2O3 doped CeO2/Pd film/(001)LaA103 with a very low pinhole density were successfully prepared using electron-beam deposition technique. The microstructure of the films was characterized by x-ray diffraction and the electrical properties were studied as a function of temperature with AC impedance spectroscopy. A brick layer model was adopted to correlate the electrical properties to the microstructure of the films, which can be simplified as either a series or a parallel equivalent circuit associated with either a fine grain or a columnar grain structure, respectively. The conductivities of the films fell between the conductivities derived from the two circuit models, suggesting that the films are of a mixed fine grain and columnar grain structure. The measured dielectric constants of the films were found smaller than that of the bulk.

Characterization, Optical and Impedance Study of ZnSe Nanostructure

2013 ◽  
Vol 699 ◽  
pp. 490-495
Author(s):  
Ramna Tripathi ◽  
Akhilesh Kumar
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Impedance Spectroscopy ◽  
Zinc Selenide ◽  
Relaxation Times ◽  
Complex Impedance ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
The Stability

Zinc selenide nanoparticle has been synthesized using soft chemical routes. The particles were capped using 2-mercaptoethanol to achieve the stability and avoid the coalescence. The as-obtained particles were characterized by X-ray diffraction (XRD), Transmission electron microscopy (TEM), UV–VIS absorption and photoluminescence (PL) spectra. The impedance studies were carried out as a function of frequency (100 Hz–1 MHz) and temperature (298–373 K) by impedance spectroscopy. An analysis of the complex impedance (z' and z") with frequency is performed assuming a distribution of relaxation times.

Mechanical Stress, Grain-boundary Relaxation, and Oxidation of Sputtered CuNi(Mn) Films

1999 ◽  
Vol 14 (4) ◽  
pp. 1286-1294 ◽  
Author(s):  
W. Brückner ◽  
W. Pitschke ◽  
S. Baunack ◽  
J. Thomas
Keyword(s):  
Grain Boundary ◽  
Microstructural Characterization ◽  
Excess Vacancy ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Boundary Relaxation ◽  
20 Nm ◽  
Atomic Rearrangement

This paper focuses on understanding stress development in CuNi42Mn1 thin films during annealing in Ar. In addition to stress-temperature measurements, resistance-temperature investigations and chemical and microstructural characterization by Auger electron spectroscopy, scanning and transmission electron microscopy, x-ray diffraction, and atomic force microscopy were also carried out. The films are polycrystalline with a grain size of 20 nm up to 450 °C. To explain the stress evolution above 120 °C, atomic rearrangement (excess-vacancy annihilation, grain-boundary relaxation, and shrinkage of grain-boundary voids) and oxidation were considered. Grain-boundary relaxation was found to be the dominating process up to 250–300 °C. A sharp transition from compressive to tensile stress between 300 and 380 °C is explained by the formation of a NiO surface layer due to reaction with the remaining oxygen in the Ar atmosphere. This oxidation is masking the inherent structural relaxation above 300 °C.

Preparation and characterization of CuInS2 nanorods and nanotubes from an elemental solvothermal reaction

2001 ◽  
Vol 16 (10) ◽  
pp. 2805-2809 ◽  
Author(s):  
Yang Jiang ◽  
Yue Wu ◽  
Shengwen Yuan ◽  
Bo Xie ◽  
Shuyuan Zhang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Electron Transfer Reaction ◽  
Solvothermal Reaction ◽  
X Ray Diffraction ◽  
Spectroscopy Analysis ◽  
X Ray ◽  
Transmission Electron

A simple and convenient solvothermal reaction has been developed to produce CuInS2 nanorods and nanotubes from the elements in ethylenediamine at 280 °C. The products were characterized by x-ray diffraction, transmission electron microscopy, high-resolution transmission electron microscopy, scanning electron microscopy, and x-ray photoelectron spectroscopy. Analysis shows that the coordinating ability of ethylenediamine and the existence of liquid In may play important roles in the growth of one-dimension nanocrystallites and the electron-transfer reaction. In addition, spherical CuInS2 micrometer particles were obtained at 350 °C.

MORPHOTROPIC PHASE BOUNDARY AND DIELECTRIC RELAXATION STUDY OF (Bi0.5Na0.5)TiO3–BaTiO3 LEAD-FREE CERAMIC

2012 ◽  
Vol 02 (03) ◽  
pp. 1250008 ◽  
Author(s):  
B. PARIJA ◽  
S. PANIGRAHI ◽  
T. BADAPANDA ◽  
T. P. SINHA
Keyword(s):  
Impedance Spectroscopy ◽  
Phase Boundary ◽  
Morphotropic Phase Boundary ◽  
Complex Impedance ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
Spectroscopy Analysis ◽  
Solid State Route ◽  
Shape Changes ◽  
Modulus Studies

We report the temperature and frequency dependence impedance spectroscopy of (1 - x) ( Bi 0.5 Na 0.5) TiO 3-x BaTiO 3 (abbreviated as BNT–BT) ceramics with 0 ≤ x ≤ 0.07 prepared by conventional solid-state route. X-ray diffraction analysis indicated that a solid solution is formed when BaTiO3 diffuses into the (Bi0.5Na0.5)TiO3 lattice and a morphotropic phase boundary between rhombohedral and tetragonal locates at x = 0.07. The microstructure indicated that the grain size reduces and the shape changes from rectangular to quasi-spherical with increase in BaTiO3 content. Complex Impedance Spectroscopy analysis suggested the presence of temperature-dependent relaxation process in the materials. The modulus mechanism indicated the non-Debye type of conductivity relaxation in the materials, which is supported by impedance data. The activation energies have been calculated from impedance, electric modulus studies and dc conductivity which suggests that the conductions are ionic in nature. The activation energy increases with increase of BT content up to x = 0.05 and decreases at x = 0.07 which also indicates the presence of morphotropic phase boundary at x = 0.07.

scholarly journals Influence of SnO2 Content on the Humidity Dependent Impedance of the MgFe2O4-Fe2O3-SnO2 Compound

Chemosensors ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 39 ◽  
Author(s):  
Maria Vesna Nikolic ◽  
Miloljub D. Lukovic
Keyword(s):  
Relative Humidity ◽  
Grain Boundary ◽  
Complex Impedance ◽  
X Ray Diffraction ◽  
X Ray ◽  
Impedance Data ◽  
Analyze Sample ◽  
Relative Humidity Range ◽  
Humidity Range ◽  
Dominant Influence

A porous MgFe2O4-Fe2O3-SnO2 bulk compound with varying SnO2 content was obtained by sintering an appropriate mixture of magnesium oxide, hematite and tin oxide nanopowders at 1000 and 1100 °C. The obtained structure was confirmed by X-ray diffraction analysis. Scanning electron microscopy was used to analyze sample morphology, showing that the addition of SnO2 resulted in an inhomogeneous microstructure with smaller grain size especially at 1000 °C. Significant grain growth of hematite grains was noted at 1100 °C. The influence of relative humidity in the range 30–90% was monitored at room temperature (25 °C) in the frequency range 42 Hz- 1 MHz. The highest reduction of impedance with humidity was noted at lower frequency. Addition of low amounts of SnO2 and sintering at 1000 °C resulted in the highest sensitivity at 105 Hz of 0.391 MΩ/%RH in the RH30–90% range, while the compound with the highest amount of SnO2 showed the largest decrease in impedance with increase in relative humidity ~26 times. All samples showed low hysteresis (below 2%). Complex impedance data was analyzed using equivalent circuits reflecting the dominant influence of the grain boundary in the lower relative humidity range (30–60%) and both grain boundary and grain components in the higher relative humidity range (60–90%).

Effect of High Temperature Deformation on Grain Boundary Defects in Yba2Cu3O7-X

1989 ◽  
Vol 169 ◽  
Author(s):  
R. Garcia ◽  
W.Z. Misiolek ◽  
R.N. Wright ◽  
K. Rajan
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Temperature ◽  
Grain Boundary ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Ceramic Superconductors ◽  
Bulk Ceramic ◽  
Transmission Electron ◽  
Lattice Distortions

AbstractThe results of transmission electron microscopy studies on YBa2Cu3O7‐x subjected to high temperature extrusion are presented. Particular emphasis is put on high temperature accommodation processes of lattice dislocations into sub‐grain boundaries. It is suggested from the electron microscopy observations that stress induced climb mechanisms for dislocations are operative. Also presented is evidence of localized lattice distortions near twin boundaries due to isothermal high temperature deformation. Preliminary results on the structure of grain boundary facets and steps is described. The implications of these results for texture development in bulk ceramic superconductors is also discussed.

IMPEDANCE SPECTROSCOPY AND MAGNETIC PROPERTIES OF AURIVILLIUS STRUCTURES

2012 ◽  
Vol 02 (03) ◽  
pp. 1250015
Author(s):  
S. K. PATRI ◽  
R. N. P. CHOUDHARY ◽  
C. RINALDI
Keyword(s):  
Electrical Properties ◽  
Impedance Spectroscopy ◽  
Complex Impedance ◽  
Hysteresis Loops ◽  
Solid State Reaction Method ◽  
Layered Perovskite ◽  
X Ray Diffraction ◽  
Orthorhombic Crystal ◽  
Orthorhombic Crystal Structure ◽  
Layered Perovskite Structure

Bi 9-x Fe 5+x Ti 3 O 27 (x = 0-3) compounds of bismuth layered perovskite structure have been successfully prepared by solid-state reaction method. X-ray diffraction (XRD) studies revealed the orthorhombic crystal structure of all the compounds. Impedance spectroscopy has been studied to characterize the electrical properties of polycrystalline Bi 9-x Fe 5+x Ti 3 O 27 (x = 0-3) compounds. The shape of complex impedance curves inferred the contribution of bulk and grain boundary effects on the electrical properties of the compounds. Temperature dependent magnetization measurements were made from 2 K to 300 K. Narrow hysteresis loops observed at room temperature indicate antiferromagnetic behavior of the compounds.

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