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Superconducting materials have an electrical resistance of zero, and so can carry large electrical currents without power dissipation or heat generation.

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Presentation on theme: "Superconducting materials have an electrical resistance of zero, and so can carry large electrical currents without power dissipation or heat generation."— Presentation transcript:

1 Superconducting materials have an electrical resistance of zero, and so can carry large electrical currents without power dissipation or heat generation. Superconductivity was first discovered in 1911, and until recently, was considered a macroscopic phenomenon. With the discovery of type-II superconductivity by Abrikosov, the prediction of vortex lattices, and their experimental observation, quantized vortices have become a central object of study in superconductivity, superfluidity, and Bose--Einstein condensation. The simplest vortex is a circle, where the beginning meets the end. İn any form of energy such as electricity through a magnetic field can move in circles. When the movement of the energy begins to spiral, a special vortex is formed. They can be visualized through the measurement of the tunneling conductance. An air gap between the pancake windings can be used to increase the central magnetic field. During the 1950s, theoretical condensedmatter physicists arrived at a solid understanding of ‘ conventional ’ superconductivity, through a pair of remarkable and important theories: the phenomenological Ginzburg-Landau theory 1950 and the microscopic BCS theory1957. Generalizations of these theories form the basis for understanding the closely related phenomenon of superfluidity, because they fall into the Lambda transmission universality class. VORTEX-ANTİVORTEX CREATİON Derived from micromagnetic simulations, a model was suggested based on dynamic vortex-antivortex (VA) creation and annihilation. This model is generally accepted for magnetic vortex core switching intiated by the excitation with in-plane Oersted fields and also by spin polarized currents. The vortex core polarization is only determined ‘ before ’ and ‘ after ’ the vortex core reversal and the evidence for the VA model is only indirect, by comparing the experimental parameters with micromagnetic simulations According to this model, when the deformation reaches full out of plane magnetisation, a vortex-antivortex pair is nucleated. Then the antivortex annihilates quickly with the original vortex, dissipates the excess energy in spin waves. PANCAKE COİL WİNDİNGS The effects of a gap at a high temperature superconducting magnet which has an insert magnet and an outsert magnet are examined. The insert magnet consists of YBCO pancake windings. The optimum gap of an insert magnet and an outsert magnet are calculated by using the response surface method. Magnetically coupled pancake vortex molecules in super multi layered cuprates and vortex molecules composed of fractional flux quanta glued by an interband phase difference solution are two examples of exotic vortex matter. JOSEPHSON EFFECT The Josephson effect is the phenomenon of electric current across two weakly coupled superconductors, separated by a very thin insulating barrier. The terms are named after British physicist Brian David Josephson, who predicted the existence of the effect in 1962. It has important applications in quantum-mechanical circuits, such as SQUIDs or RSFQ digital electronics. The critical current is an important phenomenological parameter of the device that can be affected by temperature as well as by an applied magnetic field. ( superconducting phase evolution equation ) Where U(t) and I(t) are the voltage and current across the Josephson junction, φ(t) is the "phase difference" across the junction and I c is a constant, the critical current of the junction. The physical constant h/2e is the magnetic flux quantum the inverse of which is the Josephson constant. (Josephson or weak-link current-phase relation) GİNZBURG LANDAU THEORY Around 1950 V.L. Ginzburg and L.D. Landau proposed a phenomenological theory for phase transitions. One of the more successful applications of the theory is to superconductivity and in particular to superconductors placed in a magnetic field.Some superconductors allow for magnetic field penetration through quantized current vortices when the magnetic field exceeds a threshold value. The four-dimensional extension of the Ginzburg-Landau theory, the Coleman-Weinberg model, is important in quantum field theory and cosmology. The vortex densities and vortex locations for energy minimizers in a wide range of regimes of applied fields, the precise expansion of the first critical field in a bounded domain, the existence of branches of solutions with given numbers of vortices, and the derivation of a criticality condition for vortex densities of non-minimizing solutions are some of the usual technic. [1] SOLGEL Presenting the wide range of synthetic possibilities opened by sol-gel processes in the field of organic-inorganic materials, Molecular Chemistry of Sol-Gel Derived Nanomaterials discusses the state of the art in the synthesis of the various nanomaterials. The sol may be produced from inorganic or organic precursors (e.g., nitrates or alkoxides) and may consist of dense oxide particles of polymeric clusters. Brinker expands the definition of ceramics to include organically modified materials, often called ORMOSILs or CERAMERs the main objective of this area of research is based on the formulation and development of sol-gel coatings capable of increasing paint adhesion on porous powder metal alloys, which prolongs and facilitates protection from the corrosion of the system. [3] HALL EFFECT The Hall effect is the production of a voltage difference the Hall voltage across an electrical conductor, transverse to an electric current in the conductor and a magnetic field perpendicular to the current. It was discovered by Edwin Hall in 1879. The Hall effect is the production of a voltage difference the Hall voltage across an electrical conductor, The rf Hall field in a superconductor is calculated for the applied dc magnetic field and the rf electric field both parallel to the metal surface The Hall coefficient is defined as the ratio of the induced electric field to the product of the current density and the applied magnetic field. It is a characteristic of the material from which the conductor is made, since its value depends on the type, number, and properties of the charge carriers that constitute the current. TUNNELİNG Close to an interface with an insulator a metal or a nano-object, the superconducting order parameter Δ(r) (its wavefunction) weakens gradually close to the interface an does not vanish instantaneously to zero [2]. When two superconductors with order parameters Δ 1 (r) and Δ 2 (r) are separated by a thin insulating layer, a normal metal layer (weak link) or a nano-object, they interact through tunnelling or the Andreev process. This sandwich structure is called a Josephson junction. It is dominated by the interaction energy between the two superconductors E J is their interaction energy, φ 2 -φ 1, the phase difference between the order parameters, and χ is an electromagnetic phase, which is non-zero if magnetic or electric fields are present. This additional interaction energy induces a supercurrent through the sandwich, where φ=φ 2 -φ 1 is the phase difference between the two superconductors. The Josephson coupling introduces a phase rigidity : the sandwich energy is minimal when φ=χ. If no fields are presents φ=χ=0 : the phase of the two superconductors are locked together by the Josephson coupling. SEM A Scanning SQUID Microscope is a sensitive near-field imaging system for the measurement of weakmagnetic fields by moving a Superconducting Quantum Interference Device SQUID across an area. The microscope can map out buried current- carrying wires by measuring the magnetic fields produced by the currents, or can be used to image fields produced by magnetic materials. X-RAY The reversal of the vortex core polarization in ferromagnetic nanodots via excitation of vortex gyration was discovered by time resolved X-ray microscopy. X-ray microscopy enableds to directly observe vortex core switching and localize it in space and time. UNİVERSİTY ACTİVİTİES AND CONFERENCES Dr. John D. Wallis ’ group from the University of Kent at Canterbury (1991 – 1994), financed by SERC Molecular Electronics Committee and 21st Century Material Initiative, and the synthesis of new bis(etylenedithio)tetrathiafulvalene (BEDT-TTF) type organic superconductors and developed a new method for the synthesis of fused HTS SQUID microscopes developed at University of Maryland, are now commercially available EQA-03 A Scanning SQUID Microscope forSamples at Room Temperature, it has been proved that applying sol-gel coatings on the substrate before applying the paint significantly improves the adhesion of the system at Universidad Carlos 3 de Madrid Members of the superconductivity group in Durham University have published arguably the most important J C (B,T,ε) data on superconducting materials and developed a new theoretical scaling law which successfully combines phenomenological and microscopic theory. The main activity of Bulk Superconductivity Group is Processing and properties of large grain (RE)BCO by melt processing, superconductor structure and defects, critical currents, vortex physics and flux pinning, flux trapping, critical state and E-J modelling, engineering applications and demonstrators, cryocoolers at Cambridge University. ATHENS, Ohio (March 29, 2010) — Scientists have discovered the world ’ s smallest superconductor, a sheet of four pairs of molecules less than one nanometer wide. The Ohio University-led study, published today as an advance online publication in the journal Nature Nanotechnology, provides the first evidence that nanoscale molecular superconducting wires can be fabricated, which could be used for nanoscale electronic devices and energy applications. İn Turkey Abant İzzet Baysal University, Ankara University, İnönü University, Karadeniz Tecnical University and Çukurova University have most of the significant studies about superconductivity. 500 km\h velocity magnetic train prototype was proved by a superconductivity group in Karadeniz Technical University. The SERC Molecular Electronics Committee and 21st Century Materials Initiative, England.The purpose of the study was to develop new crystalline organic substances which superconduct at significantly higher temperatures than the currently known organic superconductors İnternational Conference on Superconductivity and Magnetism ICSM 2010, Antalya, Turkey. 1.Manipulation of quantum vortex states by local current injection into mesoscopic superconductors (İnstitute of Physics, University of Tsukuba, JAPAN) 2.Attractive vortex interaction and the intermediate-mixed state (Max Planc İnstitute for Metals Research, GERMANY) 3.Exotic vortex matter: Pancake vortex molecules and fractional-flux molecules in some exotic and two component superconductors (University of Birmingham, UNİTED KİNGDOM) 4.Vortex confinement studied by scanning tunneling spectroscopy (İnstitute of Nanosciences de Paris, Universite Pierre et Marie Curie FRANCE) 5.The effect of the pinning center size on the vortex pinning by embedded ZrO2 nanoparticles (Department of Physics, Faculty of Sciences, TUNİSİA) 6.Topological hall effect in inhomogeneous pairing states of nanocentrosymmetric superconductors (Kyoto University, JAPAN) 7.Vortex-anti vortex mediated vortex core reversal in magnetic nanodots (Max Planck İnstitute for Metals Research, GERMANY) 8.Vortex structure in superconducting iron pnictide single crystals 122 and 1111 type (İnstitute of Solid State Physics, Russian Academy of Sciences, RUSSİA) 9.Performance optimization of superconducting undulators with nested HTSC loops (Karlsruhe İnstitude of Technology KİT, GERMANY) 10.YBCO pancake coils with low AC losses (Leibniz İnstitute for Solid State and Materials Research Dresden, GERMANY) 11.Current distribution in YBCO coated conductors of a toroial coil composed of multiple pancake coils (Department of Electrical Engineering, Tohoku Universiyt, JAPAN) 11.Evalution of MCDM techniques for optimal design of superconducting fault current limiters in electrical systems (Center of Excellence for Power System Automation and Operation, İran University of Scince and Technology, İRAN) [2] [7]. Formulas of Josehson Effect [8]. Break-junction setup [9]. Josepson effect in atomic contacts [10]. Hall effect sensor [11]. Ginzburg Landau theory graph [6]. Race track coils [4]. [5]. Vortex-antivortex creations 5th National Superconductivity Symposium Vortex Dynamics, Models for Tunneling,Pancake Windings and Josephson Effect Tuğçe Öztürk, Kocaeli University tugceozturk11@gmail.com [12]. Sol Gel coating [13]. Sol Gel technic[14]. Sol Gel coating Numerical simulation of formation vortex-antivortex lattice and photonic vortex [15]. SEM[16]. X ray microscopy BİBLİOGRAPHY 1. Vortices in the magnetic Gingburg Landau model by Etiene Sandiger Sylvia Serfaty 2. İnternational Conference on Superconductivity and Magnetism ICSM 2010, Antalya, Turkey. 3. Robert Carriu, Nguyen Trang An….Chemistry of Sol Gel Derived Nanomaterials. 4. http://www.physics.monash.edu.au/people/research/simula.htmlhttp://www.physics.monash.edu.au/people/research/simula.html 5. http://www.physorg.com/news93193396.htmlhttp://www.physorg.com/news93193396.html 6. http://www.matsceng.ohiostate.edu/csmm/research/topics/acloss/http://www.matsceng.ohiostate.edu/csmm/research/topics/acloss/ 7. http://en.wikipedia.org/wiki/Josephson_effecthttp://en.wikipedia.org/wiki/Josephson_effect 8. http://www.cnano-rhone-alpes.org/spip.php?article60http://www.cnano-rhone-alpes.org/spip.php?article60 9. http://iramis.cea.fr/spec/Pres/Quantro/Qsite/projects.phphttp://iramis.cea.fr/spec/Pres/Quantro/Qsite/projects.php 10. http://note19.com/2008/12/31/hall-effect-sensor/http://note19.com/2008/12/31/hall-effect-sensor/ 11. http://www.comsol.com/papers/1679/http://www.comsol.com/papers/1679/ 12.http://www.uc3m.es/portal/page/portal/grupos_investigacion/tecnologia_polvos/powder_technol ogy_research_group/Research%20areas/Sol-gel%20coatinghttp://www.uc3m.es/portal/page/portal/grupos_investigacion/tecnologia_polvos/powder_technol ogy_research_group/Research%20areas/Sol-gel%20coating [13]. http://www.sandia.gov/mst/technologies/sol-gel-glass.htmlhttp://www.sandia.gov/mst/technologies/sol-gel-glass.html [14]. http://www.porcelain-industries.com/sol-gel-thermolon-coatingshttp://www.porcelain-industries.com/sol-gel-thermolon-coatings [15]. http://www.unm.edu/~cmem/facilities/sem.htmhttp://www.unm.edu/~cmem/facilities/sem.htm [16]. http://www.voyle.net/Nano-Tsunami%20Archive%202005/07- 2005%20Archive%20News.htmhttp://www.voyle.net/Nano-Tsunami%20Archive%202005/07- 2005%20Archive%20News.htm


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