Ultrasonic Studies of Unconventional Superconductivity in the Heavy Fermion UPt3

Ultrasonic Studies of Unconventional Superconductivity in the Heavy Fermion UPt3 PDF Author: Shi-Wan Lin
Publisher:
ISBN:
Category : Fermions
Languages : en
Pages : 540

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Ultrasonic Studies of Unconventional Superconductivity in the Heavy Fermion UPt3

Ultrasonic Studies of Unconventional Superconductivity in the Heavy Fermion UPt3 PDF Author: Shi-Wan Lin
Publisher:
ISBN:
Category : Fermions
Languages : en
Pages : 540

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Book Description


Ultrasonics of High-Tc and Other Unconventional Superconductors

Ultrasonics of High-Tc and Other Unconventional Superconductors PDF Author: Moises Levy
Publisher: Academic Press
ISBN: 0323148549
Category : Science
Languages : en
Pages : 486

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Book Description
Physical Acoustics, Volume XX: Ultrasonics of High-Tc and Other Unconventional Superconductors covers the many acoustic studies of the high-Tc superconductors. This book is composed of 10 chapters that include some unconventional superconducting systems, such as superfluid 3He, heavy Fermion superconductors, and magnetic re-entrant superconductors. The introductory chapter summarizes the results that have been observed in Bardeen, Cooper, and Schriefer superconductors as functions both of temperature and magnetic field. The subsequent chapters deal with the theoretical and experimental aspects of ultrasonic study of some unconventional superconductors. Considerable chapters are devoted to the measurements with sound waves on the sintered high-Tc superconducting systems. These chapters examine first the temperature and magnetic field dependence of the velocity and elastic constants in sintered high-Tc superconductors, as well as the sound absorption and dispersion measurements on single crystals of these superconductors. Discussions on the small-sample resonant ultrasound technique that uses thin piezoelectric films and the effect of oxygen on superconducting properties and the response of sound to these additions are also provided in these chapters. The concluding chapter presents a theoretical foundation for sound measurements in the superconducting state, emphasizing the effects of multigap structures and gas anisotropy on sound attenuation in the superconducting state of the cuprate superconductors. This volume will be of great benefit to researchers in the fields of electronics technology and in applied and engineering mechanics.

Structure-property Relationships for a Heavy Fermion Superconductor, UPt3

Structure-property Relationships for a Heavy Fermion Superconductor, UPt3 PDF Author: Jung-Il Hong
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
The heavy fermion material, UPt3, exhibits the special property of unconventional superconductivity. The physical properties of UPt3 are known to be anisotropic and extremely sensitive to electron scattering by impurities (foreign atoms) and imperfections (point, line, and planar). To determine the inherent superconducting properties of UPt3, crystals of high quality, both chemically and physically, are needed.

Unconventional superconductivity in heavy-fermion compound UPt 3

Unconventional superconductivity in heavy-fermion compound UPt 3 PDF Author: Tanno Vorenkamp
Publisher:
ISBN:
Category :
Languages : en
Pages : 160

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Unconventional Superconductors

Unconventional Superconductors PDF Author: Gernot Goll
Publisher: Springer
ISBN: 3540315004
Category : Science
Languages : en
Pages : 0

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Book Description
This book offers a comprehensive summary of experiments that are especially suited to reveal the order-parameter symmetry of unconventional superconductors. It briefly introduces readers to the basic theoretical concepts and terms of unconventional superconductivity, followed by a detailed overview of experimental techniques and results investigating the superconducting energy gap and phase, plus the pairing symmetry. This review includes measurements of specific heat, thermal conductivity, penetration depth and nuclearmagnetic resonance and muon-spin rotation experiments. Further, point-contact and tunnelling spectroscopy and Josephson experiments are addressed. Current understanding is reviewed from the experimental point of view. With an appendix offering five tables with almost 200 references that summarize the present results from ambient pressure heavy-fermion and noncopper-oxide superconductors, the monograph provides a valuable resource for further studies in this field.

Quantum Criticality and Unconventional Properties of Heavy Fermion Superconductor Ce1-xYbxCoIn5

Quantum Criticality and Unconventional Properties of Heavy Fermion Superconductor Ce1-xYbxCoIn5 PDF Author: Yogesh Pratap Singh
Publisher:
ISBN:
Category : Fermions
Languages : en
Pages : 137

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Book Description
The current research interest in heavy fermion (HF) materials is for their unconventional superconductivity, their quantum critical behavior and the breakdown of Fermi liquid (FL) theory. Presently, we lack a universal understanding of the breakdown of the FL behavior in these materials. However, there are evidences which suggest that the breakdown of the FL behavior and the unconventional superconducting (SC) pairing could be the result of a zero temperature phase transition, taking place at a quantum critical point (QCP). Heavy fermions are f-electron materials in which local moments at each lattice site interact with the spin of the conduction electrons sitting at that site via an exchange coupling. There are two energy scales that result from this interaction, the Kondo temperature TK (temperature below which the local moments are screened by the spins of the conduction electrons), and the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction, which characterize the induced coupling between two local moments. These two energy scales can be tuned by external parameters such as magnetic field, pressure, and chemical substitution. Such a tuning provides an opportunity to study the rich physics of these materials. This dissertation work presents experimental and theoretical studies on ab unique member of Ce-115 family of heavy fermions, i.e., Ce1-xYbxCoIn5. In the Ce-115 family of HFs, Cerium (Ce) contributes the f-electrons to form a Kondo lattice. The substitution of Ce ions by other rare earths is a widely used approach to study this system. Our selection of ytterbium for substituting Ce-site is unique in the sense that Yb appears in the intermediate valence state in this system (unlike any other substitution), thus giving rise to many of the unusual properties, which helped in the understanding the underlying physics of SC pairing, quantum criticality and non-Fermi liquid behavior in this HF. For the purpose of the studies presented in this dissertation, we utilized electronic, magneto- and thermal transport measurements. These measurements were done under high magnetic fields and pressures wherever needed. We developed a new method to identify the field-induced QCP in this material by studying its normal state. We utilized this method to locate QCP in the parent compound CeCoIn5 and determined its evolution with Yb doping in Ce1-xYbxCoIn5. Our findings show that quantum criticality in this system is suppressed by doping with Yb and a zero field QCP is obtained for the x = 0.20 Yb-doping level. Our studies also show the evolution of the many-body electronic state as the Kondo lattice of Ce moments is transformed into an array of Ce impurities with Yb-doping. Specifically, we observe a crossover from the predominantly localized Ce moment regime to the predominantly itinerant Yb f-electronic state regime. In the crossover regime, the magneto-transport behavior of the system indicates single impurity behavior of Ce ions. This result is surprising because the resistivity and specific heat measurements suggest significant amount of coherent scattering in the system. We attribute this unusual behavior to the hybridization of conduction electrons with mixed valence Yb ions, giving rise to an intermediate energy scale (TK ~ 14 K) between the single impurity regime of Ce and Ce Kondo lattice regime. Even more intriguing are the results at even higher Yb-doping levels. Large enough Yb concentrations show an increased coherence, unlike any other member of the Ce-115 family. We also identified another QCP at a higher Yb concentration of x = 0.75. An equally interesting feature in the doping dependence of this compound is the survival of NFL behavior throughout the phase diagram. The sub-linear temperature dependence of resistivity across the whole range of Yb concentrations suggests the presence of an unconventional scattering mechanism for the conduction electrons. Thus although the quantum spin fluctuations are suppressed at around 20 % of Yb doping, the NFL behavior is observed for the whole family. Our finding of an additional high doping QCP very well explains the large value of the Sommerfeld's coefficient and the persistent NFL behavior over the whole Yb-doping range. Given the complete suppression of the antiferromagnetic fluctuations for x > 0.20 and the very robust coherence and superconductivity, the possible electron pairing mechanism may involve an exchange of virtual magnetic fluctuations or a more unconventional mechanism involving virtual fluctuations into higher lying Ce crystalline field multiplets. We analyze theoretically the dependence of the superconducting critical temperature and Kondo lattice coherence temperature on pressure for both cases of clean and disordered systems. We use the approach of the large-N mean field theory, which works very well for Kondo lattice systems.

Physical Acoustics in the Solid State

Physical Acoustics in the Solid State PDF Author: Bruno Lüthi
Publisher: Springer Science & Business Media
ISBN: 3540272798
Category : Science
Languages : en
Pages : 425

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Book Description
Physical Acoustics in the Solid State reviews the modern aspects in the field, including many experimental results, especially those involving ultrasonics. It covers practically all fields of solid-state physics. After a review of the relevant experimental techniques and an introduction to the theory of elasticity, the book details applications in the various fields of condensed matter physics.

The Search for Unconventional Superconductivity in Heavy Fermion Ytterbium Compounds at High Pressure

The Search for Unconventional Superconductivity in Heavy Fermion Ytterbium Compounds at High Pressure PDF Author: Emma Elizabeth Pearson
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Metals Abstracts

Metals Abstracts PDF Author:
Publisher:
ISBN:
Category : Metallurgy
Languages : en
Pages : 1176

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Handbook of Superconductivity

Handbook of Superconductivity PDF Author: David A. Cardwell
Publisher: CRC Press
ISBN: 1482282046
Category : Science
Languages : en
Pages : 472

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Book Description
This is the first of three volumes of the extensively revised and updated second edition of the Handbook of Superconductivity. The past twenty years have seen rapid progress in superconducting materials, which exhibit one of the most remarkable physical states of matter ever to be discovered. Superconductivity brings quantum mechanics to the scale of the everyday world where a single, coherent quantum state may extend over a distance of metres, or even kilometres, depending on the size of a coil or length of superconducting wire. Viable applications of superconductors rely fundamentally on an understanding of this intriguing phenomena and the availability of a range of materials with bespoke properties to meet practical needs. This first volume covers the fundamentals of superconductivity and the various classes of superconducting materials, which sets the context and background for Volumes 2 and 3. Key Features: Covers the depth and breadth of the field Includes contributions from leading academics and industry professionals across the world Provides hands-on guidance to the manufacturing and processing technologies A comprehensive reference, this handbook is suitable for both graduate students and practitioners in experimental physics, materials science and multiple engineering disciplines, including electronic and electrical, chemical, mechanical, metallurgy and others.