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Possibility Of Mgb2 Application To Superconducting Cavities
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Book Synopsis Possibility of MGB2 Application to Superconducting Cavities by :
Download or read book Possibility of MGB2 Application to Superconducting Cavities written by and published by . This book was released on 2002 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt: A metallic superconductor, magnesium diboride (MgB2), which has a transition temperature of (almost equal to)39 K, was discovered in early 2001. Published data taken at 10 GHz demonstrate that the material has a surface resistance comparable to niobium. This paper discusses the possibility of MgB2 as compared to Nb and Nb3Sn. Also, a possible method of fabricating a MgB2 cavity using the hot isostatic press (HIP) technique is proposed.
Book Synopsis Application of Superconducting Magnesium Diboride (MgB2) in Superconducting Radio Frequency Cavities by : Teng Tan
Download or read book Application of Superconducting Magnesium Diboride (MgB2) in Superconducting Radio Frequency Cavities written by Teng Tan and published by . This book was released on 2015 with total page 159 pages. Available in PDF, EPUB and Kindle. Book excerpt: The superconductivity in magnesium diboride (MgB2) was discovered in 2001. As a BCS superconductor, MgB2 has a record-high Tc of 39 K, high Jc of > 107 A/cm2 and no weak link behavior across the grain boundary. All these superior properties endorsed that MgB2 would have great potential in both power applications and electronic devices. In the past 15 years, MgB2 based power cables, microwave devices, and commercial MRI machines emerged and the next frontier are superconducting radio frequency (SRF) cavities. SRF cavities are one of the leading accelerator technologies. In SRF cavities, applied microwave power generates electrical fields that accelerate particle beams. Compared with other accelerator techniques, SRF cavity accelerators feature low loss, high acceleration gradients and the ability to accelerate continuous particle beams. However, current SRF cavities are made from high-purity bulk niobium and work at 2 K in superfluid helium. The construction and operational cost of SRF cavity accelerators are very expensive. The demand for SRF cavity accelerators has been growing rapidly in the past decade. Therefore, a lot of effort has been devoted to the enhancement of the performance and the reduction of cost of SRF cavities. In 2010, an acceleration gradient of over 50 MV/m has been reported for a Nb-based SRF cavity. The magnetic field at the inner surface of such a cavity is ~ 1700 Oe, which is close to the thermodynamic critical field of Nb. Therefore, new materials and technologies are required to raise the acceleration gradient of future SRF cavity accelerators. Among all the proposed approaches, using MgB2 thin films to coat the inner surface of SRF cavities is one of the promising tactics with the potential to raise both the acceleration gradient and the operation temperature of SRF cavity accelerators. In this work, I present my study on MgB2 thin films for their application in SRF cavities. C-epitaxial MgB2 thin films grown on SiC(0001) substrates showed Tc > 41 K and Jc > 107 A/cm2, which is superior to bulk MgB2 samples. Polycrystalline MgB2 thin films grown on metal substrates showed similar Tc and Jc compared with bulk samples, indicating MgB2 is suitable for coating a metal cavity. Large c-pitaxial MgB2 thin films were grown on 2-inch diameter c-sapphire wafers, showing our technique is capable of depositing large area samples. The lower critical field (Hc1) of MgB2 thin films was measured as well as it is know that bulk MgB2 has a small Hc1 and would suffer from vortex penetration at low magnetic fields. The penetrating magnetic vortices would result in loss in an applied RF field. However, due to the geometry barrier, thin film MgB2 would have a higher Hc1 than the bulk material. In my experiments, the Hc1 of MgB2 thin films increased with decreasing film thickness. At 5 K, a 100 nm epitaxial MgB2 thin film showed enhanced Hc1 ~ 1880 Oe, which is higher than Hc1 of Nb at 2 K. This showed that MgB2 coated SRF cavities have the potential to work at higher magnetic fields and higher temperature. Because the magnetic field distribution in the thin film Hc1 measurement is different from the magnetic field in a real SRF cavity, a few Nb ellipsoids were machined and coated with MgB2. The ellipsoid only has a magnetic field outside its surface and can serve as an inverse SRF cavity in the vortex penetration measurement. In the experiments, vortices penetrate into the bulk Nb ellipsoid at a magnetic field 400 Oe lower than the vortex penetration field of MgB2 coated Nb ellipsoids. This result confirmed our prediction that MgB2 coated SRF cavities could work at higher magnetic fields, thus producing higher acceleration gradients. In the last part of this thesis, I discussed how I used the dielectric resonator technique to measure the surface resistance (Rs) and Tc of MgB2 thin films. While the sensitivity of this technique was not high enough to lead to reliable Rs values, it can still serve for the determination of Tc for large area samples that are too bulky for other measurement systems.
Book Synopsis R & D on MgB2 and Nb Films at LANL for Applications to Superconducting RF Cavities by :
Download or read book R & D on MgB2 and Nb Films at LANL for Applications to Superconducting RF Cavities written by and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Power Dependence of the RF Surface Resistance of MgB2 Superconductor by :
Download or read book Power Dependence of the RF Surface Resistance of MgB2 Superconductor written by and published by . This book was released on 2005 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: Magnesium diboride (MgB2) is a superconducting material that has a transition temperature (T{sub c}) of (almost equal to)40 K, which is (almost equal to)30 K higher than niobium (Nb) that has been used for most superconducting RF cavities in the past decades. Last year, it was demonstrated that the RF surface resistance of MgB2 can be lower than Nb at 4 K. One of the problems with other high-T{sub c} materials such as YBCO was its rapid increase in RF surface resistance with higher surface magnetic fields. Recently, we have shown that MgB2 shows little increase in the surface resistance up to (almost equal to)120 Oe, equivalent of an accelerating field of (almost equal to)3 MV/m. The highest field tested was limited by available power. This result is encouraging and has made us consider fabrication of a cavity coated with MgB2 and test it. Also, there is a potential that this material has a higher critical magnetic field that enables the cavity to run at a higher gradient than Nb cavities in addition to the possibility of operation at higher temperatures.
Book Synopsis MAGNESIUM DIBORIDE (MGB2) THIN FILMS ON COPPER AND SILICON FOR RADIOFREQUENCY CAVITY AND ELECTRONIC APPLICATIONS by : Wenura Kanchana Withanage
Download or read book MAGNESIUM DIBORIDE (MGB2) THIN FILMS ON COPPER AND SILICON FOR RADIOFREQUENCY CAVITY AND ELECTRONIC APPLICATIONS written by Wenura Kanchana Withanage and published by . This book was released on 2018 with total page 179 pages. Available in PDF, EPUB and Kindle. Book excerpt: Magnesium diboride is a known material since the 1950s. However, superconductivity in MgB2 was discovered in 2001. Soon after the discovery of superconductivity in MgB2, there was a rush to understand its complex nature of superconductivity and other properties. However, current research in MgB2 is mainly focused on applications. MgB2 possesses excellent superconducting properties such as a high transition temperature (Tc) of 39 K, a high critical current density (Jc) of ~107 A·cm-2, a high thermodynamic critical field (Hc), absence of weak links at grain boundaries, etc. Because of these properties, it is considered one of the candidate materials for applications such as superconducting wires, superconducting radiofrequency (SRF) cavities, superconducting electronic devices, etc. SRF cavities play an important role in modern particle accelerators. The main objective of an SRF cavity is to accelerate charged particle beams. SRF cavities are characterized by two figures of merit: the quality factor (Q) and the accelerating gradient (Eacc). Q characterizes the energy efficiency of an RF cavity and Eacc is the average accelerating field of an RF cavity. The state-of-the-art SRF technology is based on niobium. It is a well-matured technology and it is reaching the theoretical limits on both Q and Eacc. Additionally, Nb cavities operate at 2 K, which requires large-scale liquid helium refrigeration and distribution systems. This adds substantial capital and operational costs for large particle accelerators such as HL-LHC and proposed ILC. Because of these reasons, new SRF materials with higher Q, higher Eacc, and higher operational temperatures are desired. Currently, few superconducting materials such as Nb3Sn and MgB2 are in the research and development process. Nb3Sn has a Tc of 18 K, which is significantly lower than the Tc of MgB2. MgB2-coated cavities are theoretically predicted to have higher Q and Eacc compared to Nb cavities. In addition, owing to its high Tc, MgB2-coated cavities are expected to operate above 4.2 K (20-25 K). Operation at around 20-25 K will allow the use of hydrogen- or neon-based cryocooler technology, eliminating the use of helium. This will substantially reduce the capital and operational cost of a MgB2-based accelerator. However, this will not be possible with Nb3Sn-based SRF cavities due to the low Tc of Nb3Sn. The main goal of the research presented in this thesis is to develop MgB2-coated copper superconducting radiofrequency cavities utilizing hybrid physical-chemical vapor deposition (HPCVD) technique. MgB2-coated Cu SRF cavities will have an added advantage due to the high thermal conductivity of the Cu. The excellent thermal conductivity of Cu enhances the heat transfer between the superconducting MgB2 layer and the cavity body, thus providing better resistance to thermal breakdown. RF characterization of MgB2-coated Cu is a crucial requirement because it is the first step toward the MgB2 -coated Cu SRF cavities. For these characterizations, small-sized samples (e.g., 2-inch diameter) are usually required. Among several MgB2 growth techniques, the HPCVD process produces the best quality MgB2 thin films. However, the growth of MgB2 films on Cu using the HPCVD technique is challenging as Mg, and Cu readily react to form several Mg-Cu alloys. Therefore, a new MgB2 growth process on Cu was developed by modifying the existing HPCVD process and in the new process, the deposition takes place at ~470 °C. With this new process, high-quality MgB2 thin films were successfully deposited on 2-inch diameter Cu discs, and these samples were characterized in terms of structural and superconducting properties. Surface morphology showed well-connected crystallites with no pinholes on the coating, and the cross-sectional studies showed conformal growth of MgB2 on Cu. The Tc of these samples were ~37 K and the ~107 A·cm-2 zero field Jc was observed. Most importantly, RF characterizations at 11.4 GHz showed Q close to 2 x 107 at 4 K, which was comparable to the Q of Nb. After successful RF testing of MgB2-coated Cu discs, this process was scaled up to coat 3 GHz Cu RF cavities. As the first step, a MgB2 thin film was synthesized on the inner wall of Cu tubes with dimensions (~1.5-inch inner diameter and 8-inch length), similar to a beam tube of a 3 GHz RF cavity. The MgB2 film on the Cu tubes showed conformal coating with Tc ~37 K. Next, the coating of the 3 GHz Cu test cavity was carried out. Cu test cavities were assembled using two half-cells pressed at Thomas Jefferson National Accelerator Facility (JLab) and two beam tubes machined at Temple University. The MgB2 film was successfully synthesized on the inner wall of 3 GHz test cavities and the MgB2 coating on the two half-cells showed uniform growth with Tc distributed around 35 K. However, slight damages to the cavity wall were observed and these damages were mainly due to the deformation of the Cu surface, caused by the formation of Mg-Cu alloy liquid. Current research is focused on developing damage-free MgB2-coated Cu RF cavities. In addition to MgB2 growth on Cu for SRF cavity applications, development of high-quality MgB2 thin film on Si substrates was carried out. This will be used in electronic device applications such as fabrication of hot-electron bolometers (HEB). An issue similar to the Mg-Cu reaction was observed with Si; Si and Mg react at elevated temperatures, forming Mg2Si, and this was observed at around 550°C. This reaction prevents the use of the HPCVD technique directly on Si. Previous attempts at synthesizing MgB2 films on Al2O3-buffered Si substrates at low temperatures (500-600°C) were reported. However, these films have shown extremely rough surfaces with poor superconducting properties. In this work, a ~220 nm-thick boron buffer layer was used to prevent the Mg-Si reaction, and it was observed that the boron was effective even above 700°C. High-quality MgB2 thin films were synthesized on boron-buffered Si substrates using the standard HPCVD technique. However, the resultant films showed enhanced roughness due to the polycrystalline growth. Ar ion milling at an ultra-low angle (1°) was used to smooth the MgB2 films, and the resultant films showed roughness comparable to epitaxial films grown on SiC substrates with a slight degrade in superconducting properties. Finally, Al ion implantation in the MgB2 thin film was studied and this project was carried out to synthesize MgB2 films with modified superconducting properties. In this study, 80 nm-thick MgB2 films were irradiated with a 75 keV Al ion beam. A 30 nm Au buffer layer was used on top of the MgB2 films in order to position the projected range of Al ions near the center of the MgB2 films. Al ion doses were kept between 2×1011-1×1016 atoms·cm-2. Superconducting properties and the structural properties of these Al ion irradiated films showed systematic change with the Al dose. Superconducting transition temperature decreased with increasing Al dose. Also, for the Al ion dose at or above 2 × 1014 atoms·cm-2, the irradiated samples did not show any superconducting transition. Al ion irradiated films showed an increase in the c-axis lattice parameter of MgB2 with increasing ion dose. These observed changes in the superconducting properties and structural properties of Al ion irradiated films can be attributed to the ion damage.
Book Synopsis MgB2 for Application to RF Cavities for Accelerators by :
Download or read book MgB2 for Application to RF Cavities for Accelerators written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Magnesium diboride (MgB2) has a transition temperature (T{sub c}) of (almost equal to)40 K, i.e., about 4 times as high as that of niobium (Nb). We have been evaluating MgB2 as a candidate material for radio-frequency (RF) cavities for future particle accelerators. Studies in the last 3 years have shown that it could have about one order of magnitude less RF surface resistance (Rs) than Nb at 4 K.A power dependence test using a 6 GHz TE011 mode cavity has shown little power dependence up to (almost equal to)12 mT (120 Oe), limited by available power, compared to other high-Tc materials such as YBCO. A recent study showed, however, that the power dependence of Rs is dependent on the coating method. A film made with on-axis pulsed laser deposition (PLD) has showed rapid increase in Rs compared to the film deposited by reactive evaporation method. This paper shows these results as well as future plans.
Book Synopsis Mgb2 Superconducting Wires: Basics And Applications by : Rene Flukiger
Download or read book Mgb2 Superconducting Wires: Basics And Applications written by Rene Flukiger and published by World Scientific. This book was released on 2016-08-10 with total page 667 pages. Available in PDF, EPUB and Kindle. Book excerpt: The compendium gives a complete overview of the properties of MgB2 (Magnesium Diboride), a superconducting compound with a transition temperature of Tc = 39K, from the fundamental properties to the fabrication of multifilamentary wires and to the presentation of various applications. Written by eminent researchers in the field, this indispensable volume not only discusses superconducting properties of MgB2 compounds, but also describes known preparation methods of thin films and of bulk samples obtained under high pressure methods.A unique selling point of the book is the detailed coverage of various applications based on MgB2, starting with MRI magnets and high current cables, cooled by Helium (He) vapor. High current cables cooled by liquid hydrogen are also highlighted as an interesting alternative due to the shrinking He reserves on earth. Other pertinent subjects comprise permanent magnets, ultrafine wires for space applications and wind generator projects.
Book Synopsis Tests on MgB2 for Application to SRF Cavities by : L. Phillips
Download or read book Tests on MgB2 for Application to SRF Cavities written by L. Phillips and published by . This book was released on 2006 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt: Magnesium diboride (MgB{sub 2}) has a transition temperature (T{sub c}) of {approx} 40 K, i.e., about 4 times higher than niobium (Nb). Studies in the last 3 years have shown that it could have about one order of magnitude less RF surface resistance (R{sub s}) than Nb at 4 K and seems to have much less power dependence than high-T{sub c} materials such as YBCO. However, it was also found that it will depend on the way you deposit the film. The result from on-axis pulsed laser deposition (PLD) showed rapid increase in R{sub s} with higher surface magnetic fields compared to the film deposited with reactive evaporation method.
Book Synopsis Tests on MgB2 for Application to SRF Cavities by :
Download or read book Tests on MgB2 for Application to SRF Cavities written by and published by . This book was released on 2006 with total page 77901 pages. Available in PDF, EPUB and Kindle. Book excerpt: Magnesium diboride (MgB2) has a transition temperature (Tc) of ~40 K, i.e., about four times higher than niobium (Nb). The studies in the last three years have shown that it could have about one order of magnitude less RF surface resistance (Rs) than Nb and seems much less power dependent compared to high-Tc materials such as YBCO. In this paper we will present results on the dependence of Rs on surface magnetic fields and possibly the critical RF surface magnetic field.
Book Synopsis Applied Superconductivity by : Paul Seidel
Download or read book Applied Superconductivity written by Paul Seidel and published by John Wiley & Sons. This book was released on 2015-01-29 with total page 1334 pages. Available in PDF, EPUB and Kindle. Book excerpt: This wide-ranging presentation of applied superconductivity, from fundamentals and materials right up to the details of many applications, is an essential reference for physicists and engineers in academic research as well as in industry. Readers looking for a comprehensive overview on basic effects related to superconductivity and superconducting materials will expand their knowledge and understanding of both low and high Tc superconductors with respect to their application. Technology, preparation and characterization are covered for bulk, single crystals, thins fi lms as well as electronic devices, wires and tapes. The main benefit of this work lies in its broad coverage of significant applications in magnets, power engineering, electronics, sensors and quantum metrology. The reader will find information on superconducting magnets for diverse applications like particle physics, fusion research, medicine, and biomagnetism as well as materials processing. SQUIDs and their usage in medicine or geophysics are thoroughly covered, as are superconducting radiation and particle detectors, aspects on superconductor digital electronics, leading readers to quantum computing and new devices.
Book Synopsis STATUS AND APPLICATION OF SUPERCONDUCTING CAVITIES. by : B. Bonin
Download or read book STATUS AND APPLICATION OF SUPERCONDUCTING CAVITIES. written by B. Bonin and published by . This book was released on 1994 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis ELECTRON TUNNELING STUDIES OF MATERIALS FOR SUPERCONDUCTING RADIO FREQUENCY APPLICATIONS by : Eric Lechner
Download or read book ELECTRON TUNNELING STUDIES OF MATERIALS FOR SUPERCONDUCTING RADIO FREQUENCY APPLICATIONS written by Eric Lechner and published by . This book was released on 2019 with total page 115 pages. Available in PDF, EPUB and Kindle. Book excerpt: Radio frequency (RF) cavities are the foundational infrastructure which facilitates much of the fundamental research conducted in high energy particle physics. These RF cavities utilize their unique shape to produce resonant electromagnetic fields used to accelerate charged particles. Beside their core role in fundamental physics research, RF cavities have found application in other disciplines including material science, chemistry and biology which take advantage of their unique light sources. Industry has been keen on taking advantage of accelerator technology for a multitude of applications. Particle accelerators like the one found at Jefferson Lab's Continuous Electron Beam Accelerator Facility must produce stable beams of high energy particles which is an incredibly costly endeavor to pursue. With the gargantuan size of these facilities, the cost of high-quality beam production is a matter of great importance. The quest to find highly efficient RF cavities has resulted in the widespread use of superconducting radio frequency (SRF) cavities which are the most efficient resonators that exploit a superconductor's incredibly low AC surface resistance. While metals like Cu are up to the demanding job of RF cavity particle acceleration, their efficiency at transferring RF power to the particle beam is low when they are compared with SRF Nb cavities. Nb is the standard material for all SRF cavity technology particularly for its reproducibly low surface resistance, comparatively high transition temperature and thermodynamic critical field. Using superconducting Nb is not without its drawbacks. Keeping hundreds of Nb cavities in their superconducting state under extreme RF conditions is quite a daunting task. It requires the normal state not nucleate during operation. This is achieved by producing high-quality cavities with as few defects and impurities as possible while also keeping the cavities at low temperature, usually 2K. Again, due to the sheer scale of the facilities, hundred million-dollar cryogenic plants are required to handle the heat loads during SRF cavity operation. This means even small increases in maximum accelerating gradients or decrease in cavity surface resistance results in a sizably reduced operation cost. Considerable effort has been put forth to increase the efficiency of Nb cavities toward and even beyond the theoretical maximum accelerating gradients and quality factor for a clean superconductor. Recently, a new method to produce high quality factor cavities has emerged that involves nitrogen doping the cavity. The mechanism by which N doping causes the improvement is still not well understood, but the experimental research described in this dissertation shines some light into the mechanisms behind such a drastic improvement. These insights are universal for all superconductors and may prove useful for SRF cavities beyond Nb. With Nb approaching its fundamental limits, new materials are being proposed to increase the performance of future SRF cavities which MgB2 finds itself among. MgB2 is a two-band superconductor that possesses many properties that are very attractive for the next generation of SRF cavities. One of the most important properties is MgB2's comparatively large critical temperature which in part predicts it will have a lower surface resistance than Nb at higher operating temperatures. Such behavior of MgB2 may unlock the possibility of using cryocoolers instead of costly liquid helium plants for large scale industrial use. This dissertation starts with an introduction to superconductivity, its theory, and application to SRF cavities as well as the open questions that can be addressed in Nb and the next generation of SRF materials. A description of the experimental techniques of scanning tunneling microscopy, X-ray photoelectron spectroscopy, and atomic force microscopy is presented. Our experimental investigation into Nb SRF cavity cutouts starts with a discussion of the material's limitations for SRF applications with an emphasis on the proximity effect which arises at the surface of this material due to its myriad of naturally forming oxides. The results of our scanning tunneling microscopy measurements for typically prepared Nb and nitrogen doped Nb follows and comparisons are made which show that the surface oxides are fundamentally different between these samples likely resulting in the profound enhancement of the cavity's quality factor. Experimental investigation into the native oxide of hot spot nitrogen doped Nb shows a degraded oxide and superconducting properties as compared with the cold spot. The dissertation continues with a brief introduction to MgB2, followed by our scanning tunneling and electron tunneling insights into MgB2. The dissertation is concluded with a summary of our investigations and broader impact of our research on the SRF community.
Book Synopsis Reviews Of Accelerator Science And Technology - Volume 5: Applications Of Superconducting Technology To Accelerators by : Alexander Wu Chao
Download or read book Reviews Of Accelerator Science And Technology - Volume 5: Applications Of Superconducting Technology To Accelerators written by Alexander Wu Chao and published by World Scientific. This book was released on 2013-01-28 with total page 369 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the past several decades major advances in accelerators have resulted from breakthroughs in accelerator science and accelerator technology. After the introduction of a new accelerator physics concept or the implementation of a new technology, a leap in accelerator performance followed. A well-known representation of these advances is the Livingston chart, which shows an exponential growth of accelerator performance over the last seven or eight decades. One of the breakthrough accelerator technologies that support this exponential growth is superconducting technology. Recognizing this major technological advance, we dedicate Volume 5 of Reviews of Accelerator Science and Technology (RAST) to superconducting technology and its applications.Two major applications are superconducting magnets (SC magnets) and superconducting radio-frequency (SRF) cavities. SC magnets provide much higher magnetic field than their room-temperature counterparts, thus allowing accelerators to reach higher energies with comparable size as well as much reduced power consumption. SRF technology allows field energy storage for continuous wave applications and energy recovery, in addition to the advantage of tremendous power savings and better particle beam quality. In this volume, we describe both technologies and their applications. We also include discussion of the associated R&D in superconducting materials and the future prospects for these technologies.
Book Synopsis Advances in High Temperature Superconductors and their applications by : S. MOHAN
Download or read book Advances in High Temperature Superconductors and their applications written by S. MOHAN and published by MJP Publisher. This book was released on 2019-06-20 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt: Prof. Heike Kamerlingh Onnes discovered superconductivity while measuring resistivity of mercury. Surprisingly the resistivity of mercury ceased at 4.2 K and this phenomenon was known as superconductivity. He realized the importance of this discovery in producing large magnetic fieldspl. delateIt was realized that superconductivity is in a new thermodynamic state with peculiar electric and magnetic properties. This paved the way to discover more superconductors. Simple elements such as Tin, Indium or lead showed the highest critical temperature (Tc) 7.2 K. They were called as Type 1 superconductors. Niobium-nitride was found to superconduct at 16 K at 1941 and Vanadium-silicon showed superconductive properties at 17.5 K at 1953. Nb alloys and binary or more complex compounds such as Nb3Sn (Tc – 18 K), Nb-Ti (Tc -9 K), Ga, V with Tc,23 K became type II superconductors. Thereafter, there was not much improvement in the development of superconductor although wonderful applications were expected from superconductors. After three decades, Fullerenes, like ceramic superconductors, are discovered. A decade ago MgB2 was discovered with Tc = 39 K. These superconductors were routinely produced into formof wires for producing larger magnetic fields. In all these cases cooling was effectively done by liquid Helium. A comprehensive microscopic theory of superconductivity in metals was proposed in 1957 by John Bardeen, Leon Cooper and Robert Schrieffer (the so-called “BCS” theory) for which they received the Nobel Prize in Physics. In a major breakthrough, George Bednorz and Karl Mueller discovered a brittle ceramic superconductivity in the family of cuprates at 30 K in 1986 and a new era began. Inspired by the work of Bednorz and Mueller on high temperature superconductivity (HTS), Paul Chu and his associates at the University of Houston discovered in 1987, 123 compounds. That is, YBCO (Yttrium1- Barium2-Copper3- Oxygen7) and iso-structural RBCO (Rare-earth1-Barium2-Copper3-Oxygen7) have a Tc of 93 K. Prior to 1987, all superconducting materials had lower critical temperatures (Tc’s) and therefore functioned only at temperatures near the boiling point of liquid helium (4.2 K) or liquid hydrogen (20.28 K), with the highest being Nb3Ge at 23 K. They were known as low temperature superconductors. YBCO was the first material to become superconducting above 77 K, (boiling point of liquid nitrogen) and subsequently a series of high temperature superconducting materials were discovered. These superconducting materials are widely known as High temperature superconductors as these Tc’s exceeded the limit prescribed by BCS theory. HTSCs are potentially valuable as liquid nitrogen is cheaper than liquid helium. YBCO possesses superior superconducting and physical properties. YBCO receiver coils in NMR-spectrometers have improved the resolution NMR spectrometers by a factor of 3 compared to that achievable with conventional coils. Paul Chu’s group holds the current Tc-record of 164 K in the mercury barium based cuprate superconductor under pressure. Their work led to a rapid succession of new high temperature superconducting materials, ushering in a new era in material science, chemistry and technology. Added to this the structure of Bi2Sr2Ca2Cu2O10(BiSCCO) high temperature superconductive compound having T= 110 K was reported. In 1993, mercuric-cuprates, perovskite ceramic superconductors with the transition temperatures Tc =138 K was also reported.
Book Synopsis Development of Superconducting Cavities for High Gradient Applications by : E. Kako
Download or read book Development of Superconducting Cavities for High Gradient Applications written by E. Kako and published by . This book was released on 1992 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author :Rene Flukiger Publisher :World Scientific Series in Applications of Superconductivity and Related Phenomena ISBN 13 :9789814725583 Total Pages :640 pages Book Rating :4.7/5 (255 download)
Book Synopsis MgB2 Superconducting Wires by : Rene Flukiger
Download or read book MgB2 Superconducting Wires written by Rene Flukiger and published by World Scientific Series in Applications of Superconductivity and Related Phenomena. This book was released on 2016 with total page 640 pages. Available in PDF, EPUB and Kindle. Book excerpt: The compendium gives a complete overview of the properties of MgB2 (Magnesium Diboride), a superconducting compound with a transition temperature of Tc = 39K, from the fundamental properties to the fabrication of multifilamentary wires and to the presentation of various applications. Written by eminent researchers in the field, this indispensable volume not only discusses superconducting properties of MgB2 compounds, but also describes known preparation methods of thin films and of bulk samples obtained under high pressure methods. A unique selling point of the book is the detailed coverage of various applications based on MgB2, starting with MRI magnets and high current cables, cooled by Helium (He) vapor. High current cables cooled by liquid hydrogen are also highlighted as an interesting alternative due to the shrinking He reserves on earth. Other pertinent subjects comprise permanent magnets, ultrafine wires for space applications and wind generator projects.
Book Synopsis Endless Quests: Theory, Experiments And Applications Of Frontiers Of Superconductivity by : Jiangdi Fan
Download or read book Endless Quests: Theory, Experiments And Applications Of Frontiers Of Superconductivity written by Jiangdi Fan and published by World Scientific. This book was released on 2019-01-15 with total page 325 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book is devoted to advancing and developing the frontiers of superconductivity; in particular, the theory of the Diagrammatic Iteration Approach (DIA), described in Chapter 1, is unique in the community of superconductivity.The application of DIA to electron correlation effects has allowed the tough issue of strongly-coupled electron systems to be solved, which is important for high-temperature superconductivity (HTS). DIA, when applied to a layered two-dimensional system, gives rise to marvelous outcomes that can explain all the anomalies in the normal state of HTS, and leads to a transition temperature that is dependent on quantities including the dielectric constant, electron band mass and spacing between layers. This then serves as a quantifiable guide on how to make ideal superconductors. Moreover, in such a scenario, the mechanisms of low- and high-temperature superconductivity can be unified on the basis of repulsive Coulomb interactions between electrons.The book contains rich first-hand information on experiments at the frontiers of superconductivity, as well as on relevant applications of such cutting-edge developments. For instance, Jiasu Wang, co-author of the chapter discussing the HTS Maglev train, is the person who completed the world's first HTS Maglev train. Thus, the draw of this book lies not only in its ability to marry theory, experiment and application, but also in its inclusion of research from prestigious experts of the field.
