Surface Wave Characterization of High Tc Superconductors PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download Surface Wave Characterization of High Tc Superconductors PDF full book. Access full book title Surface Wave Characterization of High Tc Superconductors by WISCONSIN UNIV-MILWAUKEE DEPT OF PHYSICS.. Download full books in PDF and EPUB format.
Author: WISCONSIN UNIV-MILWAUKEE DEPT OF PHYSICS.
Publisher:
ISBN:
Category :
Languages : en
Pages : 20
Get Book Here
Book Description
High Tc superconducting controlling elements for frequency tunable surface acoustic wave SAW filters and dispersion lines in the 0.5 to 4 GHz range have been proposed and designed. Ultrasonic attenuation and velocity measurements in sinter forged YBa2Cu3O7 indicate that the sound waves are interacting with excitations which are confined to the CuO planes. Proximity SAW coupling to a two-dimensional electron gas 2 DEG has placed limits on the localization lengths of the 2 DEG. A new phase transition has been ultrasonically discovered in the mixed state of the heavy Fermion superconductor UPt3. An anomalous increase in attenuation in the superconducting state of the reentrant superconductor system Er(1-x)Ho(x)Rh(4)B4 implies a novel interaction mechanism in this system. SAW measurements on granular superconducting films demonstrate that SAW measure the sheet resistivity of these films on a length scale comparable to the SAW wavelength. Keywords: Superconductors; Surface acoustic waves; Electron gas; Heavy fermion superconductors; Reentrant superconductors; Granular superconducting film. (jhd).
Author: WISCONSIN UNIV-MILWAUKEE DEPT OF PHYSICS.
Publisher:
ISBN:
Category :
Languages : en
Pages : 20
Get Book Here
Book Description
High Tc superconducting controlling elements for frequency tunable surface acoustic wave SAW filters and dispersion lines in the 0.5 to 4 GHz range have been proposed and designed. Ultrasonic attenuation and velocity measurements in sinter forged YBa2Cu3O7 indicate that the sound waves are interacting with excitations which are confined to the CuO planes. Proximity SAW coupling to a two-dimensional electron gas 2 DEG has placed limits on the localization lengths of the 2 DEG. A new phase transition has been ultrasonically discovered in the mixed state of the heavy Fermion superconductor UPt3. An anomalous increase in attenuation in the superconducting state of the reentrant superconductor system Er(1-x)Ho(x)Rh(4)B4 implies a novel interaction mechanism in this system. SAW measurements on granular superconducting films demonstrate that SAW measure the sheet resistivity of these films on a length scale comparable to the SAW wavelength. Keywords: Superconductors; Surface acoustic waves; Electron gas; Heavy fermion superconductors; Reentrant superconductors; Granular superconducting film. (jhd).
Author: Moises Levy
Publisher:
ISBN:
Category :
Languages : en
Pages : 23
Get Book Here
Book Description
The objective of this research project were to characterize high Tc superconductors and heavy Fermion superconductors with longitudinal and transverse ultrasonic waves and with surface acoustic waves. Sound attenuation measurements in sintered and sinter forged Y1Ba2Cu3O7 exhibited three maxima which appear to be produced by relaxation processes with activation energies in the range of 450 K, 1100 K, and 650 K. The high activation energy is associated with the middle attenuation maximum which appears to be isotropic and is the only one present in another 123 isomorph Er1Ba2Cu3O7. This is the energy of the virtual excitations proposed in some theoretical models that is required for the appearance of high Tc superconductivity. Sound measurements in a Tl based superconducting compound exhibited a frequency independent maximum at the superconducting transition. This appears to be the first attenuation effect that is directly produced by the superconducting transition itself. Such a peak has also been observed in Y1Ba2Cu3O7 after careful analysis of the data. These may be produced by interactions with superconducting fluctuations, enhanced by the two dimensional nature of the systems.
Author: Moises Levy
Publisher:
ISBN:
Category :
Languages : en
Pages : 31
Get Book Here
Book Description
The objective of this research project was to initiate a program to characterize superconductors by means of ultrasonic surface waves. Initially thin films Beta-tungsten and rocksalt superconductors were investigated. Measurements on Nb3Ge determined the superconducting fraction of the film as a function of temperature and the electron mean free path. Measurements on Nb3Sn determined the temperature dependent of superconducting energy gap and the upper critical field of the film. Measurements on several NbN films appear to indicate that there is a new interaction mechanism between the surface wave and the superconducting excitations in this rocksalt structure compound. The initial phase of the study on the effect of nickel films on the propagation of ultrasonic surface waves has been completed. Ultrasonic measurements have been performed on a polycrystalline sample of the ternary reentrant superconductor ErRh4B4 as a function of temperature where it is superconducting. Evidence is obtained for characterizing this superconductor as type II/I and for the fact that the transverse staggered susceptibility is screened by superconducting currents in the mixed state. Ultrasonic measurements have been performed in the superconducting and mixed states of bulk superconductors. (Author).
Author: X G Qiu
Publisher: Elsevier
ISBN: 0857091034
Category : Technology & Engineering
Languages : en
Pages : 450
Get Book Here
Book Description
High temperature superconductors have received a great deal of attention in recent years, due to their potential in device and power applications. This book summarises the materials science and physics of all the most important high temperature superconductors as well as discussing material growth, properties and applications. Part one covers fundamental characteristics of high temperature superconductors and high TC films such as deposition technologies, growth, transport properties and optical conductivity. Part two is concerned with growth techniques and properties of high temperature superconductors, including YBCO, BSCCO and HTSC high TC films, and electron-doped cuprates. Finally, part three describes the various applications of high temperature superconductors, from Josephson junctons and dc-superconductive quantum inference devices (dc-SQUIDs) to microwave filters. With its distinguished editor and international team of contributors, this book is an invaluable resource for those researching high temperature superconductors, in industry and academia. In light of the many recent advances in high temperature superconductors, it will benefit physicists, materials scientists and engineers working in this field, as well as in areas of industrial application, such as electronic devices and power transmission. Summarises the materials science and physics of all the most important high temperature superconductors Discusses material growth, properties and applications Outlines fundamental characteristics of high temperature superconductors and high TC films
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
Get Book Here
Book Description
Ultrasonic techniques were used to characterize the properties of high Tc and other unconventional superconductors. A pontoon technique was developed to investigate thin films with surface acoustic waves SAW. A cw sampling technique was modified in order to sensitively study vortex motion in small superconducting single crystals of YBCO. The penetration field of melt textured YBCO was observed ultrasonically and analysis of the data yields the superconducting energy gap in its domain boundaries. Phase diagrams of superconducting UPt3 were determined ultrasonically. The effect of a coherence phase transition on ultrasonic attenuation in CeCu6 was measured. A theoretical model was developed to quantitatively explain the decrease in insertion loss at the superconducting transition of a SAW delay line made with YBCO interdigital electrodes. Two sets of attenuation and velocity signatures were observed in a large single crystal La(1.85)Sr(0.15)CuO4 which correspond to the superconducting transition and to a Neel transition in the superconducting state. SAW measurements using the pontoon technique on single crystals and thin films of YBCO demonstrate the importance of pinning sites in determining the nature of vortex transitions. A two dimensional theoretical model was developed for determining the acoustic radiation impedance of resonating rectangular parallelepipeds. The effect of a surrounding medium on the resonance spectra of a vibrating solid sphere was derived theoretically, and the theoretical results compare favorably with experimental data.
Author: Moises Levy
Publisher:
ISBN:
Category :
Languages : en
Pages : 11
Get Book Here
Book Description
The objective of this research is to characterize high TC superconductors with longitudinal and transverse ultrasonic waves. Both attenuation and velocity measurements have been performed on sinter forged samples of YBa2Cu3O7, which has two CuO planes perpendicular to the c-axis per unit cell. Three elastic constants, C11, C33 and C44, out of five, for this axially symmetric sample, with 80 percent of the c-axis of platelet like crystallites aligned along the forging axis, have been determined. Three maxima in attenuation are observed at 70 K, 180 K, and 250 K when longitudinal waves are propagated perpendicular to the forging axis. Only the middle maximum is observed when either longitudinal or transverse waves propagate parallel to the forging axis or perpendicular to CuO planes. Thus, the middle maximum may be due to an isotropic interaction while the other maxima may be produced by interactions associated with distortions of the CuO planes. Frequency dependent measurements on sintered samples of YBa2Cu3O7 show that the low temperature maximum is produced by a relaxation mechanism. The activation energy of the relaxation time for this maximum is about 400 k which is near the Debye temperature of this compound. Sound measurements in a sample of Ba0.625K0.375BiO3, which has a Tc=28 k and which is postulated to be a BCS superconductor, show a maximum in attenuation around 50 K. Yttrium compound, Barium compounds, Copper oxides. (mjm).
Author: S.-L. Drechsler
Publisher: Springer Science & Business Media
ISBN: 9401007586
Category : Science
Languages : en
Pages : 568
Get Book Here
Book Description
A broad introduction to high Tc superconductors, their parent compounds and related novel materials, covering both fundamental questions of modern solid state physics (such as correlation effects, fluctuations, unconventional symmetry of superconducting order parameter) and applied problems related to short coherence length, grain boundaries and thin films. The information that can be derived from electron spectroscopy and optical measurements is illustrated and explained in detail. Descriptions widely employ the clear, relatively simple, phenomenological Ginzburg-Landau model of complex phenomena, such as vortex physics, vortex charge determination, plasmons in superconductors, Cooper pair mass, and wetting of surfaces. The first comprehensive reviews of several novel classes of materials are presented, including borocarbides and chain cuprates.
Author: D.P Tunstall
Publisher: CRC Press
ISBN: 1000445267
Category : Mathematics
Languages : en
Pages : 404
Get Book Here
Book Description
High Temperature Superconductivity provides a broad survey of high temperature superconductivity, discussing the adaptations of experimental and theoretical techniques and methods that take advantage of the revolutionary properties of high temperature superconductors. Distinguished engineers, chemists, and experimental and theoretical physicists introduce their own particular area of the field before going on to explain current theories and techniques. The book is divided into three sections: materials, mechanisms, and devices. Topics covered include synthetic approaches to the growth of new materials; optical, magnetic, and electrical characterization of synthesized materials; strong correlations; the magnon pairing mechanism; and technical background of device performance in new materials. A coherent introduction to high temperature superconductivity, this volume will be invaluable to researchers in condensed matter physics, chemistry, materials science, and engineering.
Author: Donald M Ginsberg
Publisher: World Scientific
ISBN: 9813221798
Category : Science
Languages : en
Pages : 642
Get Book Here
Book Description
This volume brings the reader up to date on transport phenomena, including electrical and thermal conductivity and infrared properties. In addition, electron tunneling and the characteristics and applications of films are discussed; the preparation of the necessary samples has proceeded, and a sizeable body of reproducible data has become available. Pressure effects are also presented; considerable progress has been made in relating them to the crystallographic and electronic structure of high temperature superconductors. The preparation and characterization of bulk samples is also reviewed.
Author: N.M. Plakida
Publisher: CRC Press
ISBN: 9780415288088
Category : Science
Languages : en
Pages : 306
Get Book Here
Book Description
Despite ten years of intensive research, many questions remain unanswered concerning the nature of the electronic structure (Fermi vs non-Fermi liquid) and mechanisms of superconductivity. Spectroscopy of High-Tc Superconductors, A Theoretical View provides a current, comprehensive review of the experimental results and theoretical interpretations concerning elementary excitation spectra (electronic, phononic, charge, and spin fluctuations) in high-Tc superconductors (HTSC). It discusses accepted microscopic models that describe the electronic structure of the copper-oxide plane - the three-band model, the generalized Emery model, the one-band Hubbard model, different kinds of the t-J model, and the regular Kondo-lattice model - and compares them with ARPES experiments. Leading Russian researchers also consider experimental results obtained by Raman scattering both by phonons and electronic excitations, including magnetic excitations in antiferromagnets in the normal phase, on almost all the types of superconducting cuprates. The results are treated theoretically with the emphasis on features thought to be related to superconductivity. The book also gives an account of the properties of the microwave surface impedance and complex conductivity as functions of temperature common for high-quality single crystals: YBCO, BSCCO, TBCCO, and BKBO. The basics of the muon method and a review of experimental results for superconducting states of different HTSC-compounds are also presented. By offering a thorough examination of current research in the field, this book will appeal to advanced students and researchers working in superconductivity and theoretical condensed matter physics.
