In this work, I am showing a faithful atomistic process of estimating the oxygen migration energetics within BSCF, oxygen migration energy exhibit a strong dependence on different local atomic structures of this doped perovskites. In addition, DFT calculations exhibit the reason of cubic phase stability of this doped perovskite in variable oxygen concentration.
Basically i have tried giving every details about the phenomenon Superconductivity in the simplest way. This is my first upload.I'll be very glad if u all give your valuable feedback. Thank u.
In this work, I am showing a faithful atomistic process of estimating the oxygen migration energetics within BSCF, oxygen migration energy exhibit a strong dependence on different local atomic structures of this doped perovskites. In addition, DFT calculations exhibit the reason of cubic phase stability of this doped perovskite in variable oxygen concentration.
Basically i have tried giving every details about the phenomenon Superconductivity in the simplest way. This is my first upload.I'll be very glad if u all give your valuable feedback. Thank u.
lecture slide on:
Gibbs free energy and Nernst Equation, Faradaic Processes and Factors Affecting Rates of Electrode Reactions, Potentials and Thermodynamics of Cells, Kinetics of Electrode Reactions, Kinetic controlled reactions,Essentials of Electrode Reactions,BUTLER-VOLMER MODEL FOR THE ONE-STEP, ONE-ELECTRON PROCESS,Current-overpotential curves for the system, Mass Transfer by Migration And Diffusion,MASS-TRANSFER-CONTROLLED REACTIONS,
Basics of Electrochemical Impedance SpectroscopyGamryInstruments
An introduction to Electrochemical Impedance Spectroscopy (EIS) theory and has been kept as free from mathematics and electrical theory as possible. If you still find the material presented here difficult to understand, don't stop reading. You will get useful information from this application note, even if you don't follow all of the discussions.
Hello, I am Subhajit Pramanick. I and my classmate, Anannya Sahaw, both presented this ppt in seminar of our Institute, Indian Institute of Technology, Kharagpur. The topic of this presentation is on exchange interaction and their consequences. It includes the basic of exchange interaction, the origin of it, classification of it and their discussions etc. We hope you will all enjoy by reading this presentation. Thank you.
An Overview of Superconductivity with Special Attention on Thermodynamic Aspe...Thomas Templin
Superconductors are special types of conductors that exhibit a variety of physical phenomena such as zero resistivity, the absence of thermoelectric effects, ideal diamagnetism, the existence of a Meissner effect, and flux quantization. The observed phenomena mean that superconductivity is a well-defined thermodynamic equilibrium state/phase that does not depend on a sample’s history. Changes of phase are entirely reversible, and once a substance has come to equilibrium with its surroundings, there is no memory of its past history.
A variety of theoretical approaches have been developed to explain superconductivity. These include the two-fluid model of superconductivity, the Ginzburg-Landau theory, and the BCS model. These models are most suitable to explain the phenomena associated with type-I superconductors, i.e., the types of superconductors that only exist when the external magnetic field is below a relatively low threshold value of Bc as well as below a transition temperature Tc close to 0 K. In the 1980s a new type of superconductors was discovered, called type-II superconductors. Type-II materials are characterized by the coexistence of normally conducting and superconducting states as well as relatively high values of the critical field and transition temperature. Type-II superconductors have been used in a variety of technological applications, such as superconducting electromagnets, MRI, particle accelerators, levitating trains, and superconducting quantum-interference devices (SQUIDs).
The superconducting state has a lower free energy than the normal state. The exclusion of the magnetic field from a superconductor leads to an increase in the free energy. The Meissner effect thus implies the existence of a thermodynamical critical field for which these two effects balance out. Knowing only the experimental temperature dependence of the critical field, the Gibbs free energy, the entropy, and the specific heat that characterize the superconducting phase can be determined.
lecture slide on:
Gibbs free energy and Nernst Equation, Faradaic Processes and Factors Affecting Rates of Electrode Reactions, Potentials and Thermodynamics of Cells, Kinetics of Electrode Reactions, Kinetic controlled reactions,Essentials of Electrode Reactions,BUTLER-VOLMER MODEL FOR THE ONE-STEP, ONE-ELECTRON PROCESS,Current-overpotential curves for the system, Mass Transfer by Migration And Diffusion,MASS-TRANSFER-CONTROLLED REACTIONS,
Basics of Electrochemical Impedance SpectroscopyGamryInstruments
An introduction to Electrochemical Impedance Spectroscopy (EIS) theory and has been kept as free from mathematics and electrical theory as possible. If you still find the material presented here difficult to understand, don't stop reading. You will get useful information from this application note, even if you don't follow all of the discussions.
Hello, I am Subhajit Pramanick. I and my classmate, Anannya Sahaw, both presented this ppt in seminar of our Institute, Indian Institute of Technology, Kharagpur. The topic of this presentation is on exchange interaction and their consequences. It includes the basic of exchange interaction, the origin of it, classification of it and their discussions etc. We hope you will all enjoy by reading this presentation. Thank you.
An Overview of Superconductivity with Special Attention on Thermodynamic Aspe...Thomas Templin
Superconductors are special types of conductors that exhibit a variety of physical phenomena such as zero resistivity, the absence of thermoelectric effects, ideal diamagnetism, the existence of a Meissner effect, and flux quantization. The observed phenomena mean that superconductivity is a well-defined thermodynamic equilibrium state/phase that does not depend on a sample’s history. Changes of phase are entirely reversible, and once a substance has come to equilibrium with its surroundings, there is no memory of its past history.
A variety of theoretical approaches have been developed to explain superconductivity. These include the two-fluid model of superconductivity, the Ginzburg-Landau theory, and the BCS model. These models are most suitable to explain the phenomena associated with type-I superconductors, i.e., the types of superconductors that only exist when the external magnetic field is below a relatively low threshold value of Bc as well as below a transition temperature Tc close to 0 K. In the 1980s a new type of superconductors was discovered, called type-II superconductors. Type-II materials are characterized by the coexistence of normally conducting and superconducting states as well as relatively high values of the critical field and transition temperature. Type-II superconductors have been used in a variety of technological applications, such as superconducting electromagnets, MRI, particle accelerators, levitating trains, and superconducting quantum-interference devices (SQUIDs).
The superconducting state has a lower free energy than the normal state. The exclusion of the magnetic field from a superconductor leads to an increase in the free energy. The Meissner effect thus implies the existence of a thermodynamical critical field for which these two effects balance out. Knowing only the experimental temperature dependence of the critical field, the Gibbs free energy, the entropy, and the specific heat that characterize the superconducting phase can be determined.
Research Inventy : International Journal of Engineering and Scienceresearchinventy
Research Inventy : International Journal of Engineering and Science is published by the group of young academic and industrial researchers with 12 Issues per year. It is an online as well as print version open access journal that provides rapid publication (monthly) of articles in all areas of the subject such as: civil, mechanical, chemical, electronic and computer engineering as well as production and information technology. The Journal welcomes the submission of manuscripts that meet the general criteria of significance and scientific excellence. Papers will be published by rapid process within 20 days after acceptance and peer review process takes only 7 days. All articles published in Research Inventy will be peer-reviewed.
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
CW RADAR, FMCW RADAR, FMCW ALTIMETER, AND THEIR PARAMETERSveerababupersonal22
It consists of cw radar and fmcw radar ,range measurement,if amplifier and fmcw altimeterThe CW radar operates using continuous wave transmission, while the FMCW radar employs frequency-modulated continuous wave technology. Range measurement is a crucial aspect of radar systems, providing information about the distance to a target. The IF amplifier plays a key role in signal processing, amplifying intermediate frequency signals for further analysis. The FMCW altimeter utilizes frequency-modulated continuous wave technology to accurately measure altitude above a reference point.
Using recycled concrete aggregates (RCA) for pavements is crucial to achieving sustainability. Implementing RCA for new pavement can minimize carbon footprint, conserve natural resources, reduce harmful emissions, and lower life cycle costs. Compared to natural aggregate (NA), RCA pavement has fewer comprehensive studies and sustainability assessments.
Industrial Training at Shahjalal Fertilizer Company Limited (SFCL)MdTanvirMahtab2
This presentation is about the working procedure of Shahjalal Fertilizer Company Limited (SFCL). A Govt. owned Company of Bangladesh Chemical Industries Corporation under Ministry of Industries.
6th International Conference on Machine Learning & Applications (CMLA 2024)ClaraZara1
6th International Conference on Machine Learning & Applications (CMLA 2024) will provide an excellent international forum for sharing knowledge and results in theory, methodology and applications of on Machine Learning & Applications.
Hierarchical Digital Twin of a Naval Power SystemKerry Sado
A hierarchical digital twin of a Naval DC power system has been developed and experimentally verified. Similar to other state-of-the-art digital twins, this technology creates a digital replica of the physical system executed in real-time or faster, which can modify hardware controls. However, its advantage stems from distributing computational efforts by utilizing a hierarchical structure composed of lower-level digital twin blocks and a higher-level system digital twin. Each digital twin block is associated with a physical subsystem of the hardware and communicates with a singular system digital twin, which creates a system-level response. By extracting information from each level of the hierarchy, power system controls of the hardware were reconfigured autonomously. This hierarchical digital twin development offers several advantages over other digital twins, particularly in the field of naval power systems. The hierarchical structure allows for greater computational efficiency and scalability while the ability to autonomously reconfigure hardware controls offers increased flexibility and responsiveness. The hierarchical decomposition and models utilized were well aligned with the physical twin, as indicated by the maximum deviations between the developed digital twin hierarchy and the hardware.
Overview of the fundamental roles in Hydropower generation and the components involved in wider Electrical Engineering.
This paper presents the design and construction of hydroelectric dams from the hydrologist’s survey of the valley before construction, all aspects and involved disciplines, fluid dynamics, structural engineering, generation and mains frequency regulation to the very transmission of power through the network in the United Kingdom.
Author: Robbie Edward Sayers
Collaborators and co editors: Charlie Sims and Connor Healey.
(C) 2024 Robbie E. Sayers
Hybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdffxintegritypublishin
Advancements in technology unveil a myriad of electrical and electronic breakthroughs geared towards efficiently harnessing limited resources to meet human energy demands. The optimization of hybrid solar PV panels and pumped hydro energy supply systems plays a pivotal role in utilizing natural resources effectively. This initiative not only benefits humanity but also fosters environmental sustainability. The study investigated the design optimization of these hybrid systems, focusing on understanding solar radiation patterns, identifying geographical influences on solar radiation, formulating a mathematical model for system optimization, and determining the optimal configuration of PV panels and pumped hydro storage. Through a comparative analysis approach and eight weeks of data collection, the study addressed key research questions related to solar radiation patterns and optimal system design. The findings highlighted regions with heightened solar radiation levels, showcasing substantial potential for power generation and emphasizing the system's efficiency. Optimizing system design significantly boosted power generation, promoted renewable energy utilization, and enhanced energy storage capacity. The study underscored the benefits of optimizing hybrid solar PV panels and pumped hydro energy supply systems for sustainable energy usage. Optimizing the design of solar PV panels and pumped hydro energy supply systems as examined across diverse climatic conditions in a developing country, not only enhances power generation but also improves the integration of renewable energy sources and boosts energy storage capacities, particularly beneficial for less economically prosperous regions. Additionally, the study provides valuable insights for advancing energy research in economically viable areas. Recommendations included conducting site-specific assessments, utilizing advanced modeling tools, implementing regular maintenance protocols, and enhancing communication among system components.
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We have compiled the most important slides from each speaker's presentation. This year’s compilation, available for free, captures the key insights and contributions shared during the DfMAy 2024 conference.
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2. What is perovskite-type oxide ?
:-same type of crystal structure as calcium titanium oxide (CaTiO3) or as ABO3
:-oxygen occupies face center
:-'A' atoms are larger than the 'B' atoms
3. What are superconductors?
At very very low temp. this type of material shows zero electrical resistance(T<TC)
and ,expel magnetic flux fields(T<Tc&H<Hc)=>Meissner effect
superconductor can carry a current indefinitely without losing any energy as there
is no resistance.
In 1911 superconductivity was first observed in mercury by Dutch physicist Heike
Kamerlingh Onnes.
he cooled mercury to the temperature of liquid helium, 4 degrees Kelvin (-269C),
its resistance suddenly disappeared.
6. BCS theory
The properties of some superconductors were modeled successfully by the efforts of John Bardeen, Leon
Cooper, and Robert Schrieffer in what is commonly called the BCS theory.
A key conceptual element in this theory is the pairing of electrons close to the Fermi level into Cooper
pairs through interaction with the crystal lattice. This pairing results from a slight attraction between the
electrons related to lattice vibrations; the coupling to the lattice is called a phonon interaction.
Pairs of electrons can behave very differently from single electrons which and must obey the Pauli
exclusion principle. The pairs of electrons can condense into the same energy level. The electron pairs
have a slightly lower energy and leave an energy gap above them on the order of .001 eV which inhibits
the kind of collision interactions which lead to ordinary resistivity. For temperatures such that the thermal
energy is less than the band gap, the material exhibits zero resistivity.
7. High Tc superconductor
High-temperature superconductors are materials that behave as superconductors at unusually high
temperatures.The first high-Tc superconductor Yttrium barium copper oxide( YBa2Cu3O7) was discovered in
1986 by IBM researchers Georg Bednorz and K. Alex Müller,who were awarded the 1987 Nobel Prize in
Physics.
Tc<30 k =>superconductors
Tc>30 k -> high-Tc superconductors
8. The Background
He did investigation of perovskites like SrTiO3 and , as a model crystal to study structural and ferroelectric
phase transition .
The key material, pure SrTiO3, could even be turned into a superconductor if it were reduced, i.e., if
oxygen were partially removed from its lattice [1.3]. The transition temperature of 0.3 K, however, was too
low Tc. Nevertheless,it was interesting that superconductivity occurred at all, because the carrier densities
were so low compared to superconducting NbO, which has carrier densities like a normal metal.
So, For increasing Tc increase carrier density,
Doping Nb in samples n = 2X1020 cm-3, enhanced electron phonon coupling led to a Tc of 0.7 K . By
further increasing the dopant concentration, the Tc even rose to 1.2 K, but not more than 1.2K.
Metallic grains of aluminum are surrounded by oxide layers acting as Josephson junctions. In granular
systems, the Tc were higher, up to 2.8 K, as compared to pure Al with Tc = 1.1 K
.
9. Involvement with the Problem
casual observation of the development of the
increase of superconducting transition
temperatures, lead to the conviction that
intermetallic compounds should not be pursued
any further. This because since 1973 the highest
Tc of 23.3 K could not be raised.
But nevertheless, the fact that superconductivity
had been observed in several complex oxides
evoked his special interest. Figure 1.1. Development of the superconducting
transition temperatures after the discovery of the
phenomenon in 1911. The materials listed are
metals or intermetallic compounds and reflect the
respective highest Tc's.
10. Involvement with the Problem
The second oxide after SrTiO3 is Li1+xTi2-xO4 spinel to exhibit surprisingly high Tc of 13 K in the Li-Ti-O
[1.8] and BaPb1-xBixO3 perovskite also exhibited the Tc of 13 K.
According to the BCS theory [1.10]
k x Tc= I.13h⍵De-1(N(E))V*
λ(Electron-phonon Coupling Constant)= N(E)xV*
N(E) =density of state at fermi level
He expected other metallic oxides to show even higher T
C
’s by increasing N(E) and/or the
electron-phonon coupling. Possibly we could enhance the coupling by polaron formation or
by the introduction of mixed valencies.
11. Involvement with the Problem
Increase N(E) ,by changing the Pb:Bi ratio, but the
compound underwent a metal-insulator transition with a
different structure, thus these attempts failed.
in Figure 1.2. There are three phases, a metallic one for
small λ and an insulating bipolaronic one for large λ, with a
superconductive phase between them, i.e., a metal-
insulator transition occurs for large λ. For intermediate λ, a
high-T, superconductor might be expected.
The question was, in which systems to look for
superconductive transitions?
Fig. 1.2. Phase diagram as a
function of electron-phonon coupling
strength(adapted from (1.1 I]).
12. The concept:-Jahn-Teller (JT) polaron model,
The guiding idea in developing the concept was influenced by the Jahn-Teller (JT) polaron model,
Jahn-Teller (JT) theorem :A nonlinear molecule or a molecular complex exhibiting an electronic
degeneracy will spontaneously distort to remove or reduce this degeneracy. Complexes containing
specific transition metal (TM) as central ions with special valency show this effect.
In the linear chain model,for small JT distortions with a stabilization energy EJT, smaller than the
bandwidth of the metal, only a slight change of the traveling electrons is present. With increasing EJT the
tendency to localization is enhanced, and for the case where EJT is comparable with the bandwidth, the
formation of JT polarons was postulated.
These composites of an electron and a surrounding lattice distortion with a high effective mass can travel
through the lattice as a whole, and a strong electron-phonon coupling exists. He knew there were many of
them. Oxides containing TM ions with partially filled eg orbitals, like Ni3+, Fe4+ or Cu2+ exhibit a strong JT
effect (Fig. 1.3), andconsidered these as possible candidates for new superconductors.
13. Copper Ions in the Oxide Octahedron
Fig. 1.3. Schematic representation of
electron orbitals for octahedrally
coordinated copper ions in oxides. For
Cu3+ with 3dn configuration, the orbitals
transforming as base functions of the cubic
eg group are half-filled, thus a
singlet ground state is formed. In the
presence of Cu2+ with 3d9 configuration,
the ground state is degenerate, and a
spontaneous distortion of the octahedron
occurs to remove this degeneracy. This is
known as the Jahn-Teller effect.
14. The Search and Breakthrough
ln La-Ni-O system. LaNiO3 is a metallic conductor with the
transfer energy of the JT-eg, electrons larger than the JT
stabilization energy, and thus the JT distortion of the oxygen
octahedra surrounding the Ni3+ is suppressed.
He replaced Ni3+ by Al3+ partially to reduce the metallic
bandwidth of the Ni3+ ions and make it comparable to the Ni3+ J-T
stabilization energy. With increasing Al3+ concentration, the
metallic characteristics (see Fig. 1.4) of the pure LaNiO3,
The idea did not work out the way he thought, so he considered
the introduction of some internal strain within the LaNiO3 lattice to
reduce the bandwidth. By replacing the La3+ ion by the smaller
Y3+ ion, keeping the Ni3+ site unaffected. Fig. 1.4. Temperature dependence of
the resistivity for metallic LaNiO3 and
LaAI1-xNixO3, where substitution of
Ni3+ by Al3+ leads to insulating
behavior for x=0.4.
15. The Search and Breakthrough
Some other scientists studied Ba-La-Cu oxide. In the
Ba-La-Cu oxide with a perovskite-type structure
containing Cu in two different valencies, all our
concept requirements seemed to be fulfilled.
By varying compositions well as the thermal
treatment , he was able to get Tc of 35 K (Fig. 1.5).
This was an incredibly high value compared to the
highest T, in the Nb3Ge superconductor(27k).
Figure 1.5. Low-temperature resistivity of a
sample with x(Ba) = 0.75, recorded for
different current densities. From [1.19]
16. It was now confirmed that Ba-doped
La2CuO4, as the superconducting
compound as it shown the Meissner
effect, and Combining the result of
the X-ray analysis, resistivity and
susceptibility measurements.
Replacing La also by other alkaline
earth In particular Sr2+ had the same
ionic radius as La3+,TC was
approaching 40 K and the
diamagnetism was even higher (see
Fig. l.12).
Fig. 1 12. Top: Resistivity as a function of temperature for Ca (O), Sr ( A ) ,and Ba
(0) substitution with substituent to La ratios of 0.2/1.8, 0.2/1.8,0.15/1.85,
respectively. Bottom: Magnetic susceptibility of these samples. The substituents
are Ca (0). Sr ( A ) , and Ba (0), with total sample masses of 0.14, 0.21. and
0.13 g, respectively.adapted from [ 1.251).
17. YBa2Cu3O7With TC of 92 K
Modification of the original
oxides by introducing the
smaller yttrium for the larger
lanthanum ion resulted in a
giant jump of TC, to 92 K in
multiphase samples.
even more impressive was
the fact that the Meissner
effect could now be
demonstrated without any
experimental difficulties with
liquid nitrogen as the coolant.
18. YBCO unit cell
The unit cell of YBa2Cu3O7-x consists of three pseudocubic elementary
perovskite unit cells. Each perovskite unit cell contains a Y or Ba atom at
the center: Ba in the bottom unit cell, Y in the middle one, and Ba in the
top unit cell. Thus, Y and Ba are stacked in the sequence [Ba–Y–Ba] along
the c-axis. All corner sites of the unit cell are occupied by Cu, which has
two different coordinations, Cu(1) and Cu(2), with respect to oxygen.
There are four possible crystallographic sites for oxygen: O(1), O(2), O(3)
and O(4).[23] The coordination polyhedron of Y and Ba with respect to
oxygen are different. The tripling of the perovskite unit cell leads to nine
oxygen atoms, whereas YBa2Cu3O7 has seven oxygen atoms and,
therefore, is referred to as an oxygen-deficient perovskite structure. The
structure has a stacking of different layers:
(CuO)(BaO)(CuO2)(Y)(CuO2)(BaO)(CuO). One of the key feature of the
unit cell of YBa2Cu3O7−x (YBCO) is the presence of two layers of CuO2.
The role of the Y plane is to serve as a spacer between two CuO2 planes.
In YBCO, the Cu–O chains are play an important role for
superconductivity. Tc is maximal near 92 K when x ≈ 0.15 and the
structure is orthorhombic. Superconductivity disappears at x ≈ 0.6, where
the structural transformation of YBCO occurs from orthorhombic to
tetragonal.
19. Characteristic part of the X-ray diffraction pattern, showing the
orthorhombic- to-tetragonal structural phase transition with
increasing Ba : La ratio. Concentration axis not to scale (adapted
from [1.20]).
20. Properties of the 123 Superconductors
What type of superconductivity
is it? Does one again have
Cooper pairing or not?
From I-V characteristics of
compound and From the well-
known Josephson formula;
VS=hv/q
they obtained q = 2e, i.e.,
Cooper pairs were present.
Steps induced by microwave
irradiation at frequency v=9.4
GHz
21. Nature of charge carrier
In La2CuO4 very little doping of divalent Ba2+ or Sr2+ and Ca2+;it was most likely that these ions substituted
for the trivalent La3+ ions. Thus,from charge-neutrality requirements, the compounds had to contain holes.
The holes were thought to be localized on the Cu ions., doping would create Cu3+ ions. Thus a mixed
Cu2+/Cu3+ state had to be present. Early photoelectron core level spectra (XPS and UPS), did not reveal
a 2p3d8 final state arising from a Cu3+ 3d8 state .
However, the excitation was consistent with the formation of holes L in the oxygen derived band, i.e., a
predominant 3d9 configuration . Photo-X-ray absorption near the edge structure was also interpreted in the
same manner by comparison with other known Cu compounds. Also the emission spectra pointed in the
same direction,
since the excitation thresholds were compatible with the presence of holes in Cu-O hybrid bands.
22. Nature of charge carrier
The electron deficiency is hereafter written in the form [Cu-O]+ as a peroxide complex in which the
probability of the hole is about 70% 3d92p, in oxygen hybrid band, and 30% 3d8 as in Cu3+ .
23. TC ∝ 1/M1/2, where M is the reduced mass.
In lower TC-> isotopes effect is more
But in ,YBa2Cu3O7 this effect is nearly absent or very small ,because of high TC
Effect of isotopes,replacing O16 by O18
Same type of crystal structure as ABO3,B cation in 6-fold coordination, surrounded by an octahedron of anions,A cation in 12-fold cuboctahedral coordination
A magnet levitating above a high-temperature superconductor, cooled with liquid nitrogen. electric current flows on the surface of the superconductor, acting to exclude the magnetic field of the magnet (Faraday's law of induction). This current effectively forms an electromagnet that repels the magnet
Fermi level is the highest energy state occupied by electrons in a material at absolute zero temperature,
123 is perovskite oxide based superconductor,now from next i will discuss how he approached this