Investigation of the Superconductivity of the Niobium Thin Films PDF Download

Author: Osamu Hamano
Publisher:
ISBN:
Category : Thin films
Languages : en
Pages : 142

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Author: Wayne R. Hudson
Publisher:
ISBN:
Category : Niobium
Languages : en
Pages : 36

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Author: Patrick A. Zukosky
Publisher:
ISBN:
Category : Dielectric films
Languages : en
Pages : 150

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Author: Melissa Rose Beebe
Publisher:
ISBN:
Category : Niobium compounds
Languages : en
Pages : 117

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Book Description
Electron correlations are the root of many interesting phenomena in materials, including phase transitions such as superconductivity and insulator-to-metal transitions, which are of great interest both for scientific understanding and for many applications. Such phase transitions can often be tailored in thin films, in which the geometry of the material is limited in one dimension. By studying how the physical structure of a thin film affects its correlated electron response, it is possible to obtain useful insight into both the nature of the electron correlations present in the material and how to control them for various applications. Niobium, an elemental superconductor, has the highest critical temperature and lower critical field of the naturally-occurring superconductors, making it attractive for many applications, particularly in the superconducting radio frequency (SRF) community. Several niobium-based compounds are also superconductors of interest; while the bulk materials are fairly well-understood, there is still a great deal to learn regarding the effects of the microstructure of thin films of these materials on their superconducting properties. Another niobium compound, niobium dioxide, exhibits a phase transition from a room-temperature insulating state to a high-temperature metallic state. Such insulator-to-metal transitions are not well-understood, even in bulk, and there is a great deal of debate over the mechanism that drives them. Experimental studies on niobium dioxide thin films are still somewhat rare and thus have the potential to contribute a great deal to the understanding of the mechanisms behind the transition. This dissertation presents structure-property correlation studies on niobium and niobium compound superconducting thin films such as those discussed above, and also reports on the first experimental studies of the light-induced insulator-to-metal transition in niobium dioxide.

Author: Kevin M. McLaughlin
Publisher:
ISBN:
Category : Thin films, Multilayered
Languages : en
Pages : 112

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Recent superconducting thin films studies have attempted to create pure metal layer films of Niobium and Titanium with the same properties of superconducting NbTi wire used in industry. These studies have all reported depression of the superconducting properties of the pure metal films which has been attributed to the proximity effect. The purpose of this research project was to construct several NbTi films composed of alloyed layers to overcome the proximity depression of superconducting properties. These films are unique in that they are the only films with both alloyed Nb/Ti superconducting and normal layers reported in the literature. Films with several different compositions and bilayer geometries were designed, constructed and their superconducting properties characterized. The films were created by the RF sputtering of alloyed targets at ambient temperatures. Characterization of the composition of the films was performed by microprobe analysis at two different electron beam voltages. A simulation of the electron beam excitation volume of the microprobe was performed to determine the difference in the two analyses and to determine whether the substrate would be found upon microprobe examination. X-ray diffraction was utilized to determine the bilayer spacing and to give a qualitative understanding of the alignment of the film microstructures. The critical temperature and upper critical magnetic field were measured to determine the superconducting properties and the extent of the proximity effect in the films. The microprobe analysis found most films to be very pure alloys except for films 6001, 6002, 6003(1) in which there were between 1-8 wt% of impurities. All films contained compositional variations on the order of 10 wt% from the design values. X-ray diffraction indicated agreement with the designed bilayer spacing in all films but 6003(2), 6005(1), and 6005(2) which had bilayer periods larger than originally designed. The proximity effect was not observed in any of the film's superconducting properties examined. T[subscript]c and H[subscript]c2 properties for the films without impurities had properties equal to that of bulk Nb/47wt% Ti. Films 6001, 6003(1) had depressed T[subscript]c and H[subscript]c2 values which were attributed to their impurity contamination. The low Ti composition in many of the films points to the inaccuracy of the deposition parameters when the films were first processed. The lack of T[subscript]c and H[subscript]c2 depression normally seen in other film studies with bilayer periods between 10-30 nm demonstrates that alloyed layers should be used to overcome the proximity effect in multilayer thin film superconductor studies. Overcoming the proximity effect should translate into a better understanding of flux pinning mechanisms in the material and increased superconducting critical currents in these films.

Author: R.D. McConnell
Publisher: Springer Science & Business Media
ISBN: 146845658X
Category : Science
Languages : en
Pages : 542

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Book Description
The Conference on the Science and Technology of Thin Film Superconductors was conceived in the early part of 1988 as a forum for the specialist in thin film superconductivity. The conference was held on November 14-18, 1988, in Co lorado Springs, Co lorado. Al though many excellent superconductivity conferences had been convened in the wake of the 1986-1987 discoveries in high temperature superconductivity, thin film topics were often dispersed among the sessions of a more general conference agenda. The response to the Conference on the Science and Technology of Thin Film Superconductors confirmed the need for an extended conference devoted to thin film superconductors. These proceedings are a major contribution to the technnology of thin film superconductivity because of the breadth and quality of the articles provided by leaders in the field. The proceedings are divided into articles on laser deposition, sputtering, evaporation, metal organic chemical vapor deposition, thick film, substrate studies, characterization, patterning and applications, and general properties. Most of the articles discuss scientific issues for high temperature thin film superconductors, although the conference was to be a forum for technology and scientific questions for both low and high temperature superconductivity. For the first day of the 5 day conference, Lawrence Berkeley Laboratory had organized an excellent set of short courses in superconduc t ing thin film devices.

Author: Kenneth B. Ullman
Publisher:
ISBN:
Category : Electric conductivity
Languages : en
Pages :

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Author: Satoru Ichinokura
Publisher: Springer
ISBN: 9811068534
Category : Science
Languages : en
Pages : 135

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Book Description
This thesis presents first observations of superconductivity in one- or two-atomic-scale thin layer materials. The thesis begins with a historical overview of superconductivity and the electronic structure of two-dimensional materials, and mentions that these key ingredients lead to the possibility of the two-dimensional superconductor with high phase-transition temperature and critical magnetic field. Thereafter, the thesis moves its focus onto the implemented experiments, in which mainly two different materials thallium-deposited silicon surfaces and metal-intercalated bilayer graphenes, are used. The study of the first material is the first experimental demonstration of both a gigantic Rashba effect and superconductivity in the materials supposed to be superconductors without spatial inversion symmetry. The study of the latter material is relevant to superconductivity in a bilayer graphene, which was a big experimental challenge for a decade, and has been first achieved by the author. The description of the generic and innovative measurement technique, highly effective in probing electric resistivity of ultra-thin materials unstable in an ambient environment, makes this thesis a valuable source for researchers not only in surface physics but also in nano-materials science and other condensed-matter physics.

Author: Pierre-Gilles de Gennes
Publisher:
ISBN: 9787519283667
Category : Superconductivity
Languages : zh-CN
Pages : 0

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Author: Silvia Haindl
Publisher: Springer
ISBN: 9783030751302
Category : Technology & Engineering
Languages : en
Pages : 390

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Book Description
This book provides a modern introduction to the growth, characterization, and physics of iron-based superconducting thin films. Iron pnictide and iron chalcogenide compounds have become intensively studied key materials in condensed matter physics due to their potential for high temperature superconductivity. With maximum critical temperatures of around 60 K, the new superconductors rank first after the celebrated cuprates, and the latest announcements on ultrathin films promise even more. Thin film synthesis of these superconductors began in 2008 immediately after their discovery, and this growing research area has seen remarkable progress up to the present day, especially with regard to the iron chalcogenides FeSe and FeSe1-xTex, the iron pnictide BaFe2-xCoxAs2 and iron-oxyarsenides. This essential volume provides comprehensive, state-of-the-art coverage of iron-based superconducting thin films in topical chapters with detailed information on thin film synthesis and growth, analytical film characterization, interfaces, and various aspects on physics and materials properties. Current efforts towards technological applications and functional films are outlined and discussed. The development and latest results for monolayer FeSe films are also presented. This book serves as a key reference for students, lecturers, industry engineers, and academic researchers who would like to gain an overview of this complex and growing research area.