This document summarizes information about ferroelectric materials and their synthesis methods. It discusses the properties of ferroelectric crystals such as barium titanate (BaTiO3), including their phase transitions and structural modifications at different temperatures. Preparation techniques for ferroelectric materials are described, such as solid state reactions and thermal decomposition. The effects of dopants like cerium dioxide on the properties of BaTiO3 ceramics are shown, including changes to Curie temperature and lattice constants. Ferroelectric ceramic-polymer composite films are also discussed as a method for producing materials with high dielectric constants.
This document describes an electrochemical study of the anodic oxidation of titanium and a TA6V alloy in chromic acid electrolytes. Voltammetry and chronoamperometry experiments were conducted to investigate the formation of oxide films. In a chromic acid electrolyte without fluoride, a thin compact oxide film forms, while in a fluoride-containing electrolyte, a duplex film of a compact layer topped by a porous columnar layer grows. The voltammetry results show a breakdown of the compact film around 3 V/SCE and that alloying elements influence porous film formation. Chronoamperometry reveals the complex growth process involves residual current contributing to thickening of both layers, with overall electrochemical efficiency decreasing over
1 Packing of spheres: Unit cell and description of crystal structure, close
packing of spheres, holes in closed-packed structures.
2 Structure of Metals: Polytypism, structures that are not closed packed, polymorphism of metals, atomic radii of metals, alloys.
3 Ionic solids: Characteristic structures of ionic solids, the rationalization of structures, the energetics of ionic bonding, consequences of lattice enthalpy.
This document discusses opportunities for using nanotechnology to improve energy applications. It notes that nanomaterials have increased surface areas and unique interface and size effects that can be exploited. Examples highlighted include using nanostructures to improve photovoltaics, hydrogen storage, and thermoelectric devices. Challenges include developing scalable synthesis methods and understanding multiscale transport phenomena. Overall, the document argues that nanoscience research has potential to transform energy technologies by manipulating energy carriers at the nanoscale and linking structures to functions.
The document describes research on photoelectrocatalytic degradation of salicylic acid using sprayed gold doped iron oxide thin films. Gold doped iron oxide films were deposited via spray pyrolysis and characterized. XRD showed the films were polycrystalline hematite. SEM showed needle-shaped grains of 100-150nm. Electrical resistivity decreased with gold doping up to 2%. The 2% gold doped film had the highest photocurrent and degraded 75% of salicylic acid in 320 minutes under visible light irradiation, making it the best photoelectrode developed in the study.
This document discusses various topics related to defects and properties in solid materials, including:
- Types of defects like non-stoichiometry, ionic conductivity, and intercalation chemistry.
- Cooperative phenomena such as magnetism, piezoelectricity, and superconductivity that arise from defects and ordering of ions/electrons in solids.
- Structural features of materials that enable ionic conduction like layered structures, framework solids, and intercalation hosts.
- Examples of materials that exhibit properties due to defects/structures, such as spinels, perovskites, and lithium ion battery electrodes.
Characterization of different dopants in TiO2 Structure by Pulsed Laser Dep...sarmad
Characterization of different dopants in TiO2 Structure by Pulsed Laser Deposition
A thesis submitted By: Khaled Z.Yahya
Supervised by: Prof.Dr. Adawiya J.Haider Prof.Dr. Raad M.S.Al-Haddad
Palestra plenária do XII Encontro da SBPMat (Campos do Jordão, setembro/outubro de 2013). Palestrante: Mercouri G Kanatzidis - Northwestern University e Argonne National Laboratory (EUA).
This document summarizes research on nanocrystalline titania powders doped with copper. Key findings include:
- Copper doping affected the phase stability of titania, promoting the rutile phase at higher temperatures.
- The 5% copper-doped titania sample had the largest degradation of methylene orange dye under visible light, indicating better photocatalytic activity than pure titania.
- UV-Vis spectroscopy estimated the band gap of the copper-doped titania to be 1.9-2 eV, lower than pure titania and allowing absorption of visible light.
This document describes an electrochemical study of the anodic oxidation of titanium and a TA6V alloy in chromic acid electrolytes. Voltammetry and chronoamperometry experiments were conducted to investigate the formation of oxide films. In a chromic acid electrolyte without fluoride, a thin compact oxide film forms, while in a fluoride-containing electrolyte, a duplex film of a compact layer topped by a porous columnar layer grows. The voltammetry results show a breakdown of the compact film around 3 V/SCE and that alloying elements influence porous film formation. Chronoamperometry reveals the complex growth process involves residual current contributing to thickening of both layers, with overall electrochemical efficiency decreasing over
1 Packing of spheres: Unit cell and description of crystal structure, close
packing of spheres, holes in closed-packed structures.
2 Structure of Metals: Polytypism, structures that are not closed packed, polymorphism of metals, atomic radii of metals, alloys.
3 Ionic solids: Characteristic structures of ionic solids, the rationalization of structures, the energetics of ionic bonding, consequences of lattice enthalpy.
This document discusses opportunities for using nanotechnology to improve energy applications. It notes that nanomaterials have increased surface areas and unique interface and size effects that can be exploited. Examples highlighted include using nanostructures to improve photovoltaics, hydrogen storage, and thermoelectric devices. Challenges include developing scalable synthesis methods and understanding multiscale transport phenomena. Overall, the document argues that nanoscience research has potential to transform energy technologies by manipulating energy carriers at the nanoscale and linking structures to functions.
The document describes research on photoelectrocatalytic degradation of salicylic acid using sprayed gold doped iron oxide thin films. Gold doped iron oxide films were deposited via spray pyrolysis and characterized. XRD showed the films were polycrystalline hematite. SEM showed needle-shaped grains of 100-150nm. Electrical resistivity decreased with gold doping up to 2%. The 2% gold doped film had the highest photocurrent and degraded 75% of salicylic acid in 320 minutes under visible light irradiation, making it the best photoelectrode developed in the study.
This document discusses various topics related to defects and properties in solid materials, including:
- Types of defects like non-stoichiometry, ionic conductivity, and intercalation chemistry.
- Cooperative phenomena such as magnetism, piezoelectricity, and superconductivity that arise from defects and ordering of ions/electrons in solids.
- Structural features of materials that enable ionic conduction like layered structures, framework solids, and intercalation hosts.
- Examples of materials that exhibit properties due to defects/structures, such as spinels, perovskites, and lithium ion battery electrodes.
Characterization of different dopants in TiO2 Structure by Pulsed Laser Dep...sarmad
Characterization of different dopants in TiO2 Structure by Pulsed Laser Deposition
A thesis submitted By: Khaled Z.Yahya
Supervised by: Prof.Dr. Adawiya J.Haider Prof.Dr. Raad M.S.Al-Haddad
Palestra plenária do XII Encontro da SBPMat (Campos do Jordão, setembro/outubro de 2013). Palestrante: Mercouri G Kanatzidis - Northwestern University e Argonne National Laboratory (EUA).
This document summarizes research on nanocrystalline titania powders doped with copper. Key findings include:
- Copper doping affected the phase stability of titania, promoting the rutile phase at higher temperatures.
- The 5% copper-doped titania sample had the largest degradation of methylene orange dye under visible light, indicating better photocatalytic activity than pure titania.
- UV-Vis spectroscopy estimated the band gap of the copper-doped titania to be 1.9-2 eV, lower than pure titania and allowing absorption of visible light.
Dielectric behaviour of Ni+2 substituted Cu Co Nanocrystalline Spinel Ferrite...inventionjournals
Herein, the dielectric properties such as permittivity (real part ε’ and imaginary part ε”) and dielectric loss tangent (tan δ) are reported for the series [Nix Cu(constant) Co0.8-x Fe2O4] where constant=0.2 with x=0.2, 0.4 and 0.6 of ferrites, prepared by Sol-Gel auto-combustion technique by using high purity metal nitrate and citric acid as a catalyst. The variation in the real part (ε’) of dielectric constant , imaginary part ( ε”) of dielectric constant and dielectric loss tangent (tan δ) are studied at room temperature in the frequency range of 100 Hz to 5 MHz. Structural characterization of the annealed samples was done with the help of X-ray diffraction method. The particle size and single phase formation of NiCuCoFe2O4 ferrite was confirmed by Xray diffraction analysis and TEM. The particle size of prepared sample was confirmed by Scherer’s formula. The effect on Particle size (t) and lattice constant (Å) is observed due to substitution of Ni2+ in Cu Co. The digital LCR meter is used to obtain the magnetic properties of prepared pallets. The variations in the structural and dielectric properties of the prepared ferrite material are discussed.
Dielectric behaviour of Ni+2 substituted Cu Co Nanocrystalline Spinel Ferrite...inventionjournals
Herein, the dielectric properties such as permittivity (real part ε’ and imaginary part ε”) and dielectric loss tangent (tan δ) are reported for the series [Nix Cu(constant) Co0.8-x Fe2O4] where constant=0.2 with x=0.2, 0.4 and 0.6 of ferrites, prepared by Sol-Gel auto-combustion technique by using high purity metal nitrate and citric acid as a catalyst. The variation in the real part (ε’) of dielectric constant , imaginary part ( ε”) of dielectric constant and dielectric loss tangent (tan δ) are studied at room temperature in the frequency range of 100 Hz to 5 MHz. Structural characterization of the annealed samples was done with the help of X-ray diffraction method. The particle size and single phase formation of NiCuCoFe2O4 ferrite was confirmed by Xray diffraction analysis and TEM. The particle size of prepared sample was confirmed by Scherer’s formula. The effect on Particle size (t) and lattice constant (Å) is observed due to substitution of Ni2+ in Cu Co. The digital LCR meter is used to obtain the magnetic properties of prepared pallets. The variations in the structural and dielectric properties of the prepared ferrite material are discussed
Synthesis and charaterization of la1 x srxmno3 perovskite nanoparticlesMai Trần
In recent times perovskite materials are extensively studied and have attracted much attention because they exhibit interesting the properties, showing potential applications in commercial, technical and biomedical. In Vietnam, perovskite materials be of interest research and applications are strong but with major research direction is to go deep into the electrical properties and the magnetic properties. The Lanthanum Strontium manganite is a perovskite-based crystal-structured ceramic material with the formula of La1-xSrxMnO3, where x describes the doping ratio. It has attracted much attention due to its good magnetic, electrical, and catalytic properties and is becoming an attractive possibility material in several biomedical applications, particularly with nano-size. In industry, this material is commonly used in as a cathode material in commercially produced solid oxide fuel cells. In this thesis, we present the Perovskite nanoparticles La1-xSrxMnO3 were successfully synthesized of the nanosize La1-xSrxMnO3 at x = 0; 0.1; 0.2; 0.3 and 0.4 which prepared by a modified sol-gel method. Structure and magnetic properties of them were systematically investigated in dependence on doped Sr ratio x. The structure was investigated by XRD and show slightly changed but magnetic properties varied strongly with changing the doping ratio x. Magnetic properties of samples were studied by Vibrating Sample Mode of Physical Properties Measurement System show at the room temperature, the samples show superparamagnetic properties with high saturated magnetization MS of 57 emu/g which strongly dependents on the doped Sr ratio x.
Characterization of Single crystal KNN Ceramics (K0.5Na0.5NbO3)Syed Ali Afzal
This document describes the characterization of potassium sodium niobate (KNN) single crystals grown via a slow-cooling technique. Key points:
1) KNN single crystals up to 4x4x8 mm in size were grown and showed an orthorhombic perovskite structure.
2) Dielectric measurements found phase transitions from rhombohedral to orthorhombic at -100°C, orthorhombic to tetragonal at 214°C, and tetragonal to cubic at 433°C.
3) Piezoelectric coefficient d33 peaked at 130°C with a maximum value of 220 pC/N, decreasing above 210°C
Raman Spectroscopy revealing the nano scale structural details of prototype f...ashu pasha
Ferroelectricity and lattice dynamics are inter related and the Raman is a very powerfull tool to investigate lattice dynamics. Structural details of Barium Tiatane , a proto type ferroelectric have been elucidated with micro Raman.
This document discusses the effect of heating rate on the structural and optical properties of silicon and magnesium co-doped zirconia nanopowders prepared by a sol-gel method. X-ray diffraction analysis showed that different heating rates between 1-10°C/min affected the formation of tetragonal and cubic phases, crystallinity, and particle size. Ultraviolet-visible spectroscopy showed that the band gap energy of the doped zirconia crystals decreased depending on the heating rate, with a minimum band gap of around 3-3.2 eV.
Effect of sintering time on the particle size and dielectric properties of La...ijceronline
International Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
Structures of Solids
The components can be arranged in a regular repeating three-dimensional array (a crystal lattice), which results in a crystalline solid, or more or less randomly to produce an amorphous solid. Crystalline solids have well-defined edges and faces, diffract x-rays, and tend to have sharp melting points
What are the different types of solids?
There are four different types of crystalline solids: molecular solids, network solids, ionic solids, and metallic solids. A solid's atomic-level structure and composition determine many of its macroscopic properties, including, for example, electrical and heat conductivity, density, and solubility.
What makes a solid a solid?
Solids can hold their shape because their molecules are tightly packed together. ... Atoms and molecules in liquids and gases are bouncing and floating around, free to move where they want. The molecules in a solid are stuck in a specific structure or arrangement of atoms.
What are the 2 types of solids?
Solids can be classified into two types: crystalline and amorphous. Crystalline solids are the most common type of solid. They are characterized by a regular crystalline organization of atoms that confer a long-range order.
What are the examples of solids?
Examples of Solids
Gold.
Wood.
Sand.
Steel.
Brick.
Rock.
Copper.
Brass.
What are the 3 characteristics of solids?
A solid has definite volume and shape, a liquid has a definite volume but no definite shape and gas has neither a definite volume nor shape.
...
Solids
Definite shape (rigid)
Definite volume.
Particles vibrate around fixed axes.
How do you describe solids?
A solid is a sample of matter that retains its shape and density when not confined. The adjective solid describes the state, or condition, of matter having this property. The atom s or molecule s of matter in the solid-state are generally compressed as tightly as the repulsive forces among them will allow.
What is the structure of a solid?
In a solid, molecules are packed together, and it keeps its shape. The matter is the "stuff" of the universe, the atoms, molecules, and ions that make up all physical substances. In a solid, these particles are packed closely together and are not free to move about within the substance
What are some properties of solids?
Explanation:
A solid has a definite shape and volume.
Solids, in general, have a higher density.
In solids, intermolecular forces are strong.
The diffusion of a solid into another solid is extremely slow.
Solids have high melting points.
What are the 4 types of structures?
There are four types of structures;
Frame: made of separate members (usually thin pieces) put together.
Shell: encloses or contains its contents.
Solid (mass): made almost entirely of matter.
liquid (fluid): braking fluid making the brakes.
1) Room temperature electrochemical synthesis allows for uniform coatings of thermoelectric bismuth telluride (Bi2Te3) with tunable composition and stoichiometry in an inexpensive and scalable process.
2) The document details the electrochemical synthesis of Bi2Te3 from bismuth chloride and a tellurium glycolate precursor in an ionic liquid electrolyte.
3) Constant potential electrodeposition at different potentials produced Bi2Te3 coatings with nanoparticle or nanostructured morphologies and varying Bi:Te atomic ratios, demonstrating the ability to control composition through the electrochemical method.
This document summarizes research on using titanium suboxides for photoelectrochemical water splitting. Titanium dioxide (TiO2) is commonly investigated for this application due to its suitable band positions, but has limitations due to its large band gap. The researchers grew TiO2 "flower-like structures" on a titanium mesh substrate and treated them at high temperature in a reducing atmosphere to introduce oxygen vacancies. This created substoichiometric titanium suboxides with higher carrier density and photocurrent efficiency compared to stoichiometric TiO2. Functionally graded titanium oxide fibers were also evaluated and showed the highest photocurrent efficiency of 34.8% due to a gradient composition of TiO2, Magneli phases, and rutile TiO
The document describes the iron-carbon phase diagram. It discusses the various phases that exist in iron-carbon alloys including δ-ferrite, austenite, α-ferrite, and cementite. It outlines the crystal structures and carbon solubility limits of each phase. The diagram shows the phase regions and transformation temperatures. Key features include the eutectoid reaction where austenite transforms to ferrite and cementite at 727°C, and the eutectic point where liquid transforms to austenite and cementite at 1148°C. Micrographs show the microstructures of pearlite, martensite, and other phases. Examples are given to illustrate interpretation of phase transformations on
This document discusses phase transformations in steels. It begins by defining different types of phase transformations and listing common phases in steel alloys. It then discusses the kinetics of phase transformations, including nucleation and growth. Various transformation products are described, including pearlite, martensite, bainite and spheroidite. Isothermal transformation (TTT) diagrams and continuous cooling transformation (CCT) diagrams are explained as tools to predict phase transformations during heating and cooling processes. The effects of alloying elements and different heat treatments on the transformation behavior are also summarized.
1. The document discusses the synthesis of nanosized porous materials like BEA and LTA zeolites and preparation of metal-containing molecular sieves via methods like ion exchange followed by gamma irradiation or thermal reduction.
2. Pt and Cu clusters were incorporated into BEA zeolite via ion exchange and treated with gamma irradiation or plasma treatment to form metal clusters inside the zeolite pores. HRTEM showed the metal clusters were 1-2nm in size and located inside the zeolite channels.
3. The metal-doped zeolites were used to make thin films via spin coating. GI-XRD and ellipsometry showed the films had Pt clusters and thickness of 200-
final accept-Optical and structural properties of TiO2 nanopowders with Co-Ce...nasrollah najibi ilkhchy
This document discusses a study on the optical and structural properties of TiO2 nanopowders doped with 2 mol% cerium and 4 mol% cobalt. X-ray diffraction analysis showed that cerium doping inhibited the formation of the rutile phase of titanium dioxide and promoted retention of the anatase phase at higher calcination temperatures. Optical absorption spectroscopy indicated that doping reduced the band gap of titanium dioxide from 3.21 eV to 3.14-3.20 eV. The crystallite size decreased with doping while the surface area increased compared to undoped titanium dioxide.
Synthesis & characterization of magnesium ferrites & exploring its microwave ...Nikita Gupta
Magnesium ferrite was synthesized using a co-precipitation method with magnesium nitrate and iron nitrate precursors. The synthesized powder was characterized using XRD, FESEM, and VSM. XRD analysis showed the sample had a hexagonal structure with crystallite size of approximately 80-300nm. FESEM images showed uniformly distributed grains of 100-300nm in size with some porosity. VSM analysis showed the sample was ferromagnetic with increasing magnetization as annealing temperature increased, reaching 20.8 emu/g when annealed at 950 degrees Celsius. Microwave absorption measurements from 8-12GHz showed return losses up to 0.874dB, indicating the sample could potentially be used for microwave absorption applications
Point defects are imperfections in crystalline solids that disrupt the periodic arrangement of atoms. There are three main types of point defects: vacancies, interstitials, and substitutions. Vacancies occur when an atom is missing from its lattice site, interstitials occur when an atom occupies a normally unoccupied site between lattice positions, and substitutions occur when one atom replaces another atom in the lattice. Point defects are thermally activated and their concentration increases with temperature according to an Arrhenius relationship. Diffusion, which is the thermally activated movement of atoms or ions in solids, allows point defects to move within the crystal structure. The rate of diffusion depends on factors like defect concentration, activation energy, and temperature.
Point defects are zero-dimensional imperfections in a crystal structure, such as vacancies, interstitials, and substitutions. Line defects like dislocations are one-dimensional, while planar defects like stacking faults are two-dimensional. Volume defects are three-dimensional imperfections. Point defects influence material properties by increasing disorder and entropy. Their equilibrium concentration depends on temperature and activation energy according to the Arrhenius equation. Common point defects in ionic crystals include Schottky defects, which maintain charge neutrality by pairing cation and anion vacancies, and Frenkel defects involving an ion moving into an interstitial site. Dopants can introduce carriers that make semiconductors n-type or p-type.
The document summarizes two methods for synthesizing nanostructured ceramic powders: the mimic alkoxide method and hydrothermal synthesis.
The mimic alkoxide method involves dissolving a cerium precursor in alcohol and adding it dropwise to a precipitating solution, producing nanocrystalline powder with primary particles around 15nm that are well-sintered at lower temperatures than aqueous precipitation.
Hydrothermal synthesis uses high-temperature high-pressure water to precipitate oxides from precursor solutions, producing crystalline anhydrous powder without needing calcination or milling, and employing inexpensive raw materials. It is highlighted for making solid-solution particles for multilayer ceramic capacitors.
UiPath Test Automation using UiPath Test Suite series, part 5DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 5. In this session, we will cover CI/CD with devops.
Topics covered:
CI/CD with in UiPath
End-to-end overview of CI/CD pipeline with Azure devops
Speaker:
Lyndsey Byblow, Test Suite Sales Engineer @ UiPath, Inc.
Maruthi Prithivirajan, Head of ASEAN & IN Solution Architecture, Neo4j
Get an inside look at the latest Neo4j innovations that enable relationship-driven intelligence at scale. Learn more about the newest cloud integrations and product enhancements that make Neo4j an essential choice for developers building apps with interconnected data and generative AI.
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Dielectric behaviour of Ni+2 substituted Cu Co Nanocrystalline Spinel Ferrite...inventionjournals
Herein, the dielectric properties such as permittivity (real part ε’ and imaginary part ε”) and dielectric loss tangent (tan δ) are reported for the series [Nix Cu(constant) Co0.8-x Fe2O4] where constant=0.2 with x=0.2, 0.4 and 0.6 of ferrites, prepared by Sol-Gel auto-combustion technique by using high purity metal nitrate and citric acid as a catalyst. The variation in the real part (ε’) of dielectric constant , imaginary part ( ε”) of dielectric constant and dielectric loss tangent (tan δ) are studied at room temperature in the frequency range of 100 Hz to 5 MHz. Structural characterization of the annealed samples was done with the help of X-ray diffraction method. The particle size and single phase formation of NiCuCoFe2O4 ferrite was confirmed by Xray diffraction analysis and TEM. The particle size of prepared sample was confirmed by Scherer’s formula. The effect on Particle size (t) and lattice constant (Å) is observed due to substitution of Ni2+ in Cu Co. The digital LCR meter is used to obtain the magnetic properties of prepared pallets. The variations in the structural and dielectric properties of the prepared ferrite material are discussed.
Dielectric behaviour of Ni+2 substituted Cu Co Nanocrystalline Spinel Ferrite...inventionjournals
Herein, the dielectric properties such as permittivity (real part ε’ and imaginary part ε”) and dielectric loss tangent (tan δ) are reported for the series [Nix Cu(constant) Co0.8-x Fe2O4] where constant=0.2 with x=0.2, 0.4 and 0.6 of ferrites, prepared by Sol-Gel auto-combustion technique by using high purity metal nitrate and citric acid as a catalyst. The variation in the real part (ε’) of dielectric constant , imaginary part ( ε”) of dielectric constant and dielectric loss tangent (tan δ) are studied at room temperature in the frequency range of 100 Hz to 5 MHz. Structural characterization of the annealed samples was done with the help of X-ray diffraction method. The particle size and single phase formation of NiCuCoFe2O4 ferrite was confirmed by Xray diffraction analysis and TEM. The particle size of prepared sample was confirmed by Scherer’s formula. The effect on Particle size (t) and lattice constant (Å) is observed due to substitution of Ni2+ in Cu Co. The digital LCR meter is used to obtain the magnetic properties of prepared pallets. The variations in the structural and dielectric properties of the prepared ferrite material are discussed
Synthesis and charaterization of la1 x srxmno3 perovskite nanoparticlesMai Trần
In recent times perovskite materials are extensively studied and have attracted much attention because they exhibit interesting the properties, showing potential applications in commercial, technical and biomedical. In Vietnam, perovskite materials be of interest research and applications are strong but with major research direction is to go deep into the electrical properties and the magnetic properties. The Lanthanum Strontium manganite is a perovskite-based crystal-structured ceramic material with the formula of La1-xSrxMnO3, where x describes the doping ratio. It has attracted much attention due to its good magnetic, electrical, and catalytic properties and is becoming an attractive possibility material in several biomedical applications, particularly with nano-size. In industry, this material is commonly used in as a cathode material in commercially produced solid oxide fuel cells. In this thesis, we present the Perovskite nanoparticles La1-xSrxMnO3 were successfully synthesized of the nanosize La1-xSrxMnO3 at x = 0; 0.1; 0.2; 0.3 and 0.4 which prepared by a modified sol-gel method. Structure and magnetic properties of them were systematically investigated in dependence on doped Sr ratio x. The structure was investigated by XRD and show slightly changed but magnetic properties varied strongly with changing the doping ratio x. Magnetic properties of samples were studied by Vibrating Sample Mode of Physical Properties Measurement System show at the room temperature, the samples show superparamagnetic properties with high saturated magnetization MS of 57 emu/g which strongly dependents on the doped Sr ratio x.
Characterization of Single crystal KNN Ceramics (K0.5Na0.5NbO3)Syed Ali Afzal
This document describes the characterization of potassium sodium niobate (KNN) single crystals grown via a slow-cooling technique. Key points:
1) KNN single crystals up to 4x4x8 mm in size were grown and showed an orthorhombic perovskite structure.
2) Dielectric measurements found phase transitions from rhombohedral to orthorhombic at -100°C, orthorhombic to tetragonal at 214°C, and tetragonal to cubic at 433°C.
3) Piezoelectric coefficient d33 peaked at 130°C with a maximum value of 220 pC/N, decreasing above 210°C
Raman Spectroscopy revealing the nano scale structural details of prototype f...ashu pasha
Ferroelectricity and lattice dynamics are inter related and the Raman is a very powerfull tool to investigate lattice dynamics. Structural details of Barium Tiatane , a proto type ferroelectric have been elucidated with micro Raman.
This document discusses the effect of heating rate on the structural and optical properties of silicon and magnesium co-doped zirconia nanopowders prepared by a sol-gel method. X-ray diffraction analysis showed that different heating rates between 1-10°C/min affected the formation of tetragonal and cubic phases, crystallinity, and particle size. Ultraviolet-visible spectroscopy showed that the band gap energy of the doped zirconia crystals decreased depending on the heating rate, with a minimum band gap of around 3-3.2 eV.
Effect of sintering time on the particle size and dielectric properties of La...ijceronline
International Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
Structures of Solids
The components can be arranged in a regular repeating three-dimensional array (a crystal lattice), which results in a crystalline solid, or more or less randomly to produce an amorphous solid. Crystalline solids have well-defined edges and faces, diffract x-rays, and tend to have sharp melting points
What are the different types of solids?
There are four different types of crystalline solids: molecular solids, network solids, ionic solids, and metallic solids. A solid's atomic-level structure and composition determine many of its macroscopic properties, including, for example, electrical and heat conductivity, density, and solubility.
What makes a solid a solid?
Solids can hold their shape because their molecules are tightly packed together. ... Atoms and molecules in liquids and gases are bouncing and floating around, free to move where they want. The molecules in a solid are stuck in a specific structure or arrangement of atoms.
What are the 2 types of solids?
Solids can be classified into two types: crystalline and amorphous. Crystalline solids are the most common type of solid. They are characterized by a regular crystalline organization of atoms that confer a long-range order.
What are the examples of solids?
Examples of Solids
Gold.
Wood.
Sand.
Steel.
Brick.
Rock.
Copper.
Brass.
What are the 3 characteristics of solids?
A solid has definite volume and shape, a liquid has a definite volume but no definite shape and gas has neither a definite volume nor shape.
...
Solids
Definite shape (rigid)
Definite volume.
Particles vibrate around fixed axes.
How do you describe solids?
A solid is a sample of matter that retains its shape and density when not confined. The adjective solid describes the state, or condition, of matter having this property. The atom s or molecule s of matter in the solid-state are generally compressed as tightly as the repulsive forces among them will allow.
What is the structure of a solid?
In a solid, molecules are packed together, and it keeps its shape. The matter is the "stuff" of the universe, the atoms, molecules, and ions that make up all physical substances. In a solid, these particles are packed closely together and are not free to move about within the substance
What are some properties of solids?
Explanation:
A solid has a definite shape and volume.
Solids, in general, have a higher density.
In solids, intermolecular forces are strong.
The diffusion of a solid into another solid is extremely slow.
Solids have high melting points.
What are the 4 types of structures?
There are four types of structures;
Frame: made of separate members (usually thin pieces) put together.
Shell: encloses or contains its contents.
Solid (mass): made almost entirely of matter.
liquid (fluid): braking fluid making the brakes.
1) Room temperature electrochemical synthesis allows for uniform coatings of thermoelectric bismuth telluride (Bi2Te3) with tunable composition and stoichiometry in an inexpensive and scalable process.
2) The document details the electrochemical synthesis of Bi2Te3 from bismuth chloride and a tellurium glycolate precursor in an ionic liquid electrolyte.
3) Constant potential electrodeposition at different potentials produced Bi2Te3 coatings with nanoparticle or nanostructured morphologies and varying Bi:Te atomic ratios, demonstrating the ability to control composition through the electrochemical method.
This document summarizes research on using titanium suboxides for photoelectrochemical water splitting. Titanium dioxide (TiO2) is commonly investigated for this application due to its suitable band positions, but has limitations due to its large band gap. The researchers grew TiO2 "flower-like structures" on a titanium mesh substrate and treated them at high temperature in a reducing atmosphere to introduce oxygen vacancies. This created substoichiometric titanium suboxides with higher carrier density and photocurrent efficiency compared to stoichiometric TiO2. Functionally graded titanium oxide fibers were also evaluated and showed the highest photocurrent efficiency of 34.8% due to a gradient composition of TiO2, Magneli phases, and rutile TiO
The document describes the iron-carbon phase diagram. It discusses the various phases that exist in iron-carbon alloys including δ-ferrite, austenite, α-ferrite, and cementite. It outlines the crystal structures and carbon solubility limits of each phase. The diagram shows the phase regions and transformation temperatures. Key features include the eutectoid reaction where austenite transforms to ferrite and cementite at 727°C, and the eutectic point where liquid transforms to austenite and cementite at 1148°C. Micrographs show the microstructures of pearlite, martensite, and other phases. Examples are given to illustrate interpretation of phase transformations on
This document discusses phase transformations in steels. It begins by defining different types of phase transformations and listing common phases in steel alloys. It then discusses the kinetics of phase transformations, including nucleation and growth. Various transformation products are described, including pearlite, martensite, bainite and spheroidite. Isothermal transformation (TTT) diagrams and continuous cooling transformation (CCT) diagrams are explained as tools to predict phase transformations during heating and cooling processes. The effects of alloying elements and different heat treatments on the transformation behavior are also summarized.
1. The document discusses the synthesis of nanosized porous materials like BEA and LTA zeolites and preparation of metal-containing molecular sieves via methods like ion exchange followed by gamma irradiation or thermal reduction.
2. Pt and Cu clusters were incorporated into BEA zeolite via ion exchange and treated with gamma irradiation or plasma treatment to form metal clusters inside the zeolite pores. HRTEM showed the metal clusters were 1-2nm in size and located inside the zeolite channels.
3. The metal-doped zeolites were used to make thin films via spin coating. GI-XRD and ellipsometry showed the films had Pt clusters and thickness of 200-
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Magnesium ferrite was synthesized using a co-precipitation method with magnesium nitrate and iron nitrate precursors. The synthesized powder was characterized using XRD, FESEM, and VSM. XRD analysis showed the sample had a hexagonal structure with crystallite size of approximately 80-300nm. FESEM images showed uniformly distributed grains of 100-300nm in size with some porosity. VSM analysis showed the sample was ferromagnetic with increasing magnetization as annealing temperature increased, reaching 20.8 emu/g when annealed at 950 degrees Celsius. Microwave absorption measurements from 8-12GHz showed return losses up to 0.874dB, indicating the sample could potentially be used for microwave absorption applications
Point defects are imperfections in crystalline solids that disrupt the periodic arrangement of atoms. There are three main types of point defects: vacancies, interstitials, and substitutions. Vacancies occur when an atom is missing from its lattice site, interstitials occur when an atom occupies a normally unoccupied site between lattice positions, and substitutions occur when one atom replaces another atom in the lattice. Point defects are thermally activated and their concentration increases with temperature according to an Arrhenius relationship. Diffusion, which is the thermally activated movement of atoms or ions in solids, allows point defects to move within the crystal structure. The rate of diffusion depends on factors like defect concentration, activation energy, and temperature.
Point defects are zero-dimensional imperfections in a crystal structure, such as vacancies, interstitials, and substitutions. Line defects like dislocations are one-dimensional, while planar defects like stacking faults are two-dimensional. Volume defects are three-dimensional imperfections. Point defects influence material properties by increasing disorder and entropy. Their equilibrium concentration depends on temperature and activation energy according to the Arrhenius equation. Common point defects in ionic crystals include Schottky defects, which maintain charge neutrality by pairing cation and anion vacancies, and Frenkel defects involving an ion moving into an interstitial site. Dopants can introduce carriers that make semiconductors n-type or p-type.
The document summarizes two methods for synthesizing nanostructured ceramic powders: the mimic alkoxide method and hydrothermal synthesis.
The mimic alkoxide method involves dissolving a cerium precursor in alcohol and adding it dropwise to a precipitating solution, producing nanocrystalline powder with primary particles around 15nm that are well-sintered at lower temperatures than aqueous precipitation.
Hydrothermal synthesis uses high-temperature high-pressure water to precipitate oxides from precursor solutions, producing crystalline anhydrous powder without needing calcination or milling, and employing inexpensive raw materials. It is highlighted for making solid-solution particles for multilayer ceramic capacitors.
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2. What`s a ferroelectric crystal ?
A ferroelectric crystal exibits an electric dipole moment even in
the absence of an external electric field.
Why ?
In the ferroelectric state, the center of positive charge of the
crystal does not coincide with the center of the negative charge.
Ferroelectricity in such crystals appears above a certain
temperature (transition temperature) and disappears above a
specific temperature (Curie temperature).
Tt < Tferroelectric < TC (paraelectric)
(pyroelectric)
3. Characteristics of ferroelectric crystals
Ferroelectric materials exhibit hysteresis properties similar to
ferromagnetic materials...
that means...
in ferroelelctric materials exist domains...
but the crystal as a whole is un polarised
The presence of an external electric field
with altering intensity...
makes the domains change size and shape
E
(polarisation)
4. 1943 were discovered the ferroelectric properties of BaTiO3
Ferroelectric properties are determined by the behavior of the
central ion Ti
193 – 273 K orthorhombic system, Ti4+ is displaced toward
the diagonal of the elementary cell wall [110].
183 K there is a phase trasition: ferroelectric orthorhombic
phase – ferroelectric rhombohedral phase.
278 K there is a phase transition: ferroelectric orthorhombic
phase – ferroelectric tetragonal phase (278 – 393).
393 K phase transition: ferroelectric tetragonal – ferroelectric
Pseudocubic (regular structure).
Properties of BaTiO3
5. cubic tetragonal orthorhombic
Structural Modifications of BaTiO3 and their Characteristics
Pm-3m P4mm Amm2
a = 4.0000 Å a = 3.9945 Å
c = 4.0335 Å
a = 3.9900 Å
b = 5.6690 Å
c = 5.6820 Å
Ba – O
2.828 Å
Ti – O
2.000 Å
Ba – O
2.826 – 2.838 Å
Ti – O
1.863 – 2.170 Å
Ba – O
2.784 – 2.898 Å
Ti – O
1.929 – 2.090 Å
6. hexagonal trigonal
Structural Modifications of BaTiO3 and their Characteristics
P63/mmc R3m
a = 5.7350 Å
c = 14.0500 Å
a = 3.0010 Å
α = 89.85 °
Ba – O
2.852 – 2.956 Å
Ti – O
1.948 – 2.015 Å
Ba – O
2.771 – 2.896 Å
Ti – O
1.881 – 2.129 Å
7. What causes the ferroelectricity in such crystals ?
Oxygen – vacancy defects
Cubic phase PbTiO3
8 neighboring oxigens move toward the defect about 0.14 Å
4 neighboring lead atoms move toward the defect about 0.07 Å
2 vacancy – closest Ti atoms move outward the defect about 0.17 Å
Atom
Charge
Perfect crystal With vacancy Displacement
Ti(1)
Ti(2)
O(3)
O(4)
O(5)
O(6)
O(7)
O(8)
O(9)
O(10)
Pb(11)
Pb(12)
Pb(13)
Pb(14)
2.48 2.38
2.48 2.38
-1.39 -1.38
-1.39 -1.38
-1.39 -1.38
-1.39 -1.38
-1.39 -1.38
-1.39 -1.38
-1.39 -1.38
-1.39 -1.38
1.70 1.71
1.70 1.71
1.70 1.71
1.70 1.71
0.17
0.17
0.14
0.14
0.14
0.14
0.14
0.14
0.14
0.14
0.07
0.07
0.07
0.07
Relax. Energy (init.-optim.) = 11.5 eV
8. Tetragonal phase PbTiO3
Oxygen – vacancy defects
Atom
Charge
Perfect crystal With vacancy
Displacement
xy z total
Ti(1)
Ti(2)
O(3)
O(4)
O(5)
O(6)
O(7)
O(8)
O(9)
O(10)
Pb(11)
Pb(12)
Pb(13)
Pb(14)
2.37 2.26
2.40 2.29
-1.32 -1.30
-1.32 -1.30
-1.32 -1.30
-1.32 -1.30
-1.38 -1.36
-1.38 -1.36
-1.38 -1.36
-1.38 -1.36
1.74 1.69
1.74 1.69
1.74 1.69
1.74 1.69
0.00 0.53 0.53
0.00 0.06 0.06
0.12 0.18 0.21
0.12 0.18 0.21
0.12 0.18 0.21
0.12 0.18 0.21
0.08 0.24 0.25
0.08 0.24 0.25
0.08 0.24 0.25
0.08 0.24 0.25
0.03 0.00 0.03
0.03 0.00 0.03
0.03 0.00 0.03
0.03 0.00 0.03
Ferroelectricity due to the dipole
moment along z - axis
z
4 upper neighboring oxigens move toward the vacancy
4 neighboring lead atoms move outward the vacancy
2 vacancy – closest Ti atoms move outward the vacancy
4 lower neighboring oxigens move outward the vacancy
Relax. Energy
(init.-optim.) = 5.1 eV
9. The influence of the dopant (La) in the cubic phase
The relaxation of the lattice shows these movements:
Ti moves outward the defect(La) by 0.07 Å along <111>
O moves toward the defect by 0.02 Å along z – axis
(studied by means of advanced quantum-chemical method based on Hartree-Fock theory)
10. What happens with the extra e
incoming with La ?
Asymetric lattice distortion
Localized in local energy level
Charge distribution along z
z
Asymetric distortion of the cubic lattice
2 – Localization within the band gap
No increasement of electrical conductivity
(electrical dipole)
La in the cubic phase facilitates the phase transition (tetragonal)
Relaxation energy = 0.94 eV
(Coloumb destabilizing forces)
12. Hexagonal BaTiO3
Two zone – centre structural
phase transitions:
P63/mmc
Non-polar C2221
222 K
74 K ferroelectric P21phase
The same distortions of the TiO6 octahedra as in c-BT are observed
Similar chains of dipoles
13. Is there any change of ferroelectricity related
to particle size ?
Variation of permittivity for
presintered samples obtained from
Powder of different - sized
A, ∅ < 1.3μm
B, 1.3 < ∅ < 6.6 μm
C, 6.6 < ∅ < 18 μm
D, 18 < ∅ < 26 μm
E, 26 < ∅ < 50 μm
∅(particle) = f (temperature, sintering period)
No ∅ changes are observed for 1 hour at 1200°C
∅ of different particles is checked with microscope
spherical (1.3 < ∅ < 6.6 mm)
Influence of the form of the particles
cubic particles (1 mm)
The permittivity of the particles resulted:
spherical 202 cubic 215
Permittivity depends strongly on the way of
preparation and treatment of the materials
Studies on ferroelectricity in small coloidal
dots of BaTiO3 (0.5 nm) showed the presence
of large off-center displacements.
14. Efects of the additives on the properties of
BaTiO3 ceramics
Composition
ρB
(gcm-3)
TC
(°C)
Lattice
a (Å)
Constants
c (Å)
Ratio
c/a
BaTiO3
(BaTiO3)99.95(CeO2)0.05
(BaTiO3)99.5(CeO2)0.5
(BaTiO3)99(CeO2)1
(BaTiO3)98.5(CeO2)1.5
(BaTiO3)98(CeO2)2
(BaTiO3)97(CeO2)3
(BaTiO3)94.4(CeO2)5.6
(BaTiO3)93.8(CeO2)16.2
5.42
5.46
5.58
5.70
5.74
5.76
5.80
5.86
5.91
106
103
102.5
101.5
100.5
92
92
Smeared
Smeared
3.9965
3.9994
3.9962
3.9985
3.9958
4.0007
4.0008
4.0033
4.0112
4.0328
4.0358
4.0351
4.0310
4.0239
4.0130
4.0088
4.0083
3.9885
1.009083
1.009101
1.009734
1.008128
1.007032
1.003074
1.001999
1.001249
0.994341
A large number of dopands can be accommodated in the lattice of perovskites due to its
capability to host ions of different size causing substitution of Ba2+ or Ti4+, like: Pb2+,
Bi3+, Cu2+, Ca2+, Si4+, La3+, Ce2+, La2O3, CeO2
tetragonal – cubic – tetragonal (reverse direction)
15. Variation of permittivity (ε)
with temperature (T) °C
Variation of bulk density (ρB)
with CeO2 concentration
Variation of with CeO2 concentration
Variation of permittivity, bulk density and Curie
temperature for CeO2 doped BaTiO3(tetragonal) samples
(A): 0.05 mol% CeO2
(B): 0.5
(C): 1.0
(D): 1.5
(E): 2.0
(F): 3.0
(G): 5.6
(H): 16.2
16. 1
2
Tetragonal BaTiO3
Cubic BaTiO3
Formation of a solid solution from CeO2 doping BaTiO3
Two possible substitutions occur in the structure of BaTiO3
Ionic radii: Ce4+, Ti4+, O2-
1.01Å 0.68 Å 1.32 Å
Increasing the Ce4+ concentration conversion of the lattice from
tetragonal-cubic takes place decreasing the magnitude of spontaneous
polarisation, thus the permittivity.
17. Some preparation methods for ferroelectrics
Pulsed laser deposition
Thermal decomposition
Thin films by Sol – gel process
Patterned microstructures by sol-electrodeposition
Solid state reactions
Polymer composite films
Hydrothermal epitaxial thin films formed on epitaxial
electrode
18. Solid – state preparation method
BaCO3 + TiO2 = BaTiO3 + CO2
BaCO3 and TiO2 are mixed well in agate mortar
The mixture was heated at 1300°C – 6 h in air
Ball milled
Addition of additives
(BaTiO3)1-x + (CeO2)x
CuO - (BaTiO3)1-x + (AgNO3)x
Mixture was pressed in pellets and sintered at certain temperatures
0.05 -16.2 % mol
1 - 6 % mol
Measurements of the respective permittivities
19. Thermal decomposition as a preparation method
This method is applied to produce nm-sized BaTiO3 crystalites
Two steps thermal treatment of BaTiO(C2O4) x 2 H2O
1- treatment at 400°C for 1h under O2 flow
BaTiO(C2O4) x 2 H2O + O2 → BaTiO3 + CO2 + H2O
2- treatment of formed BaTiO3 at various temperatures in vacuum
Average particle size analyzed by (TEM), impurities by (FT-IR)
BaTiO3 crystalites with an average size of 16.5 nm were obtained
Dielectric constat (BaTiO3 16.5nm) resulted almost 400
20. Ferroelectric ceramic – polymer composite films
Purpose: Production of ferroelectric ceramic – polymer composite
films with high dielectric constant (ε) for high frequency electronics
Materials: BaTiO3 filler as the best known ferroelectric ceramics
Trimethylolpropan triacrylate (TMPTA monomer)
2,2 – dimethoxy – 2 – phenylacetophenone (photoinciator)
1- 1% solution of the photoinitiator was mixed with the main solution
2- BaTiO3 was mixed with TMPTA at various filler concentrations (main sol.)
3- Each solution was mixed with the photoinitiator
4- Few drops of each formulation were squezed between microscope slides
and exposed to UV -light
5- The thin flims prepared were examined with laser scanning confocal
microscopy
6- Dielectric measurements Impedance/Gain analyser, at 25°C, 1kHz
22. Dependence of cluster size and dielectric constant
from the volume fraction of BaTiO3 particles
The non – uniformity of the particle distribution caused by cluster formation
doesn`t affect macroscopic dielectric properties of BaTiO3 – polymer composites
23. Hydrothermal epitaxial thin films formed
on epitaxial electrode
BaTiO3 pseudocubic epitaxial thin films formed on epitaxial
electrode layers of SrRuO3 on SrTiO3 single crystal substrates
TiO2powder + Ba(OH)2(aq) → BaTiO3(H2O,OH-, CO3
2-)
90°C
pH = 14
Reaction time = 24 h
Product washed and recovered CO2 - free water
SrRuO3-SrTiO3 single-crystal was placed in the bottle before adding TiO2 powder
where SrRuO3 serves as electrode film and SrTiO3 as substrate for the over growing BaTiO3
The thin film obtained was pseudocubic and grown in the same
orientation as SrRuO3 and SrTiO3
24. XRD analyses showed the lattice constants for: BaTiO3, SrRuO3, SrTiO3
4.018 Å 4.037 Å 3.905 Å
Bright-field cross-section TEM micrograph
of the BaTiO3/SrRuO3/SrTiO3 film
SEM micrograph of the BaTiO3 thin film
grown on SrRuO3/SrTiO3 substrate
a) XRD pattern of BaTiO3/SrRuO3/SrTiO3
b) off-axis Φ-scans of (310) reflection of
BaTiO3 thin film, (220) of SrRuO3 buffer
layer and (220) reflection of SrTiO3
25. Preliminary investigations on epitaxial BaTiO3/SrRuO3 thin films show:
Before heat-treatment high losses of (ε ~ 450, δ ~100 %)
After heat-treatment (300 °C) low losses are observed (ε ~ 200, δ ~ 8 %)
To improve the electrical properties heating treatment of the film is suggested
1- T = 30 to 250°C 0.4 wt.% due to surface water and OH-
2- T = 250 to 800 °C 1.1 wt.% due to lattice H2O and OH-
3- T = 800 to 900 °C 0.25 wt.% due to CO2 evolution
Dielectric constant vs frequency as a
function of heat treatment for 1h.
Dielectric constant vs frequency as a
function of heat treatment at 300°C
26. Net weight loss as a function of
heat-treatment for 1h
TGA plot of BaTiO3 heated from
RT to 900°C at 2°C/min
OH- incorporation within the lattice is inevitable in hydrothermal
synthesized materials
1- Heating from RT to 300°C shows a decrease in lattice parameters
2- after 800 °C lattice begins to convert in tetragonal phase
3- over 1000 °C the films become fully tetragonal
Location of water within the crystal lattice: a) highly defective shell
b)BaCO3/BaTiO3 interfaces
27. Applications of titanates
BaTiO3, SrTiO3, PbTiO3 because of high dielectric constants
At room temperature and piezoelectric properties find
Applications in electronics.
Capacitors
Piezoelectric tranducers
Thermistors
Actuators
(large electro – optic coefficients and high photorefractive sensitivity)
Sensors
28. The stored charge Q in a capacitor is
proportional with the applied voltage U
Q ~ U
The proportional factor is the capacitance C
Q = CU
C = ε0 x εr x A/d ε0 = absolute dielectric constant (absolute permittivity)
εr = relative dielectric constant (relative permittivity)
(depends on insulation material)
A = plate surface in cm2
d = distance between plates in cm
The capacitor and application of permittivity
C = capacitance in F
29. Applications
Characteristics of Ag doped CuO-BaTiO3 CO2 Sensor
Ag doped CuO-BaTiO3 is a sensor that detects CCO2 in air from 100 ppm – 10 %
Ag increases the absorption of CO2 on the surface (catalyst)
Ag absorbs CO2 molecules to produce Ag2CO3
How does the doping ratio influence the sensitivity ?
30. Influence of the annealing
Ag doped CuO-BaTiO3 is a sensor is significantly affected by
sintering temperature
Sintering time 4h, CCO2 = 5000 ppm
31. Literature
1.- Randall, J. Am. Cheram. Soc., 81 (1998) p. 979
2.- M.R. Srinivasan, M.S.Multani, P. Ayyub, R. Vuayaraghavan, Ferroelectrics,
51 (1983) p. 137
3.- J. C. Cousseins, Phys. Stat. Sol. (a), 160 (1997), p. 255
4.- Z. Jiao, F. Chen, Sensors 2 (2002), p. 366-373
5.- J. C. Bourdreaux, R. H. Dauskardt, Mat. Res. Society 9 (2001) p. 1-6
6.- A. T. Chien, X. Xu, J. H. Kim, J. S. Speck, J. Mater. Res. Vol. 14, 8 (1999) p. 3330-3339
7.- H. Pinto, A. Stashans, P. Sanchez, Cendro de Investigation en Fisica de la Materia
Condensada. Corporacion de Fisica Fundamental y Aplicada. Apartado 17-12.637,
Quito Ecuador
8.- Edgar Patino, Arvidis Stashans, Cendro de Investigation en Fisica de la Materia
Condensada. Corporacion de Fisica Fundamental y Aplicada. Apartado 17-12.637,
Quito Ecuador
9.- Sheyla Serrano, Carlos Duque, Paul Medina, Arvids Stashans, Cendro de
Investigation en Fisica de la Materia Condensada. Corporacion de Fisica
Fundamental y Aplicada. Apartado 17-12.637, Quito Ecuador
10.- H. Fu, L. Bellaiche, J. Phys. Rev, Letters Vol. 91, 25 (2003) p. 1-4
11.- J. Paletto, G. Grange, R. Goutte, L. Eyraud, J. Appl. Phys. Vol 7 (1974)
p. 78-84
12.- M AA Issa, N M Molokhia, Z H Dughaish J. Appl. Phys. Vol. 16 (1983)
p. 1109-1114