Download or read book Magnetic Fluctuations in a Heavy Fermion Alloy Close to an Antiferromagnetic Quantum Critical Point written by Almut Schröder and published by . This book was released on 2000 with total page 101 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Quantum Critical Fluctuations in the Heavy Fermion Compound Ce Ni0 935Pd0 065 2Ge2 written by and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Electric resistivity, specific heat, magnetic susceptibility, and inelastic neutron scattering experiments were performed on a single crystal of the heavy fermion compound Ce(Ni0.935Pd0.065)2Ge2 in order to research the spin fluctuations near an antiferromagnetic (AF) quantum critical point (QCP). The resistivity and the specific heat coefficient for T ≤ 1 K exhibit the power law behavior expected for a 3D itinerant AF QCP ([rho](T) ~ T3/2 and [gamma](T) ~ [gamma]0 - bT1/2). However, for 2 ≤ T ≤ 10 K, the susceptibility and specific heat vary as log T and the resistivity varies linearly with temperature. In addition, despite the fact that the resistivity and specific heat exhibit the non-Fermi liquid behavior expected at a QCP, the correlation length, correlation time, and staggered susceptibility of the spin fluctuations remain finite at low temperature. In conclusion, we suggest that these deviations from the divergent behavior expected for a QCP may result from alloy disorder.
Download or read book Quantum Critical Phenomena of Valence Transition written by Shinji Watanabe and published by Springer Nature. This book was released on 2024-01-27 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book comprehensively presents an unconventional quantum criticality caused by valence fluctuations, which offers theoretical understanding of unconventional Fermi-liquid properties in cerium- and ytterbium-based heavy fermion metals including CeCu2(Si,Ge)2 and CeRhIn5 under pressure, and quasicrystal β-YbAlB4 and Yb15Al34Au51. The book begins with an introduction to fundamental concepts for heavy fermion systems, valence fluctuation, and quantum phase transition, including self-consistent renormalization group theory. A subsequent chapter is devoted to a comprehensive description of the theory of the unconventional quantum criticality based on a valence transition, featuring explicit temperature dependence of various physical quantities, which allows for comparisons to relevant experiments. Lastly, it discusses how ubiquitous the valence fluctuation is, presenting candidate materials not only in heavy fermions, but also in strongly correlated electrons represented by high-Tc superconductor cuprates. Introductory chapters provide useful materials for learning fundamentals of heavy fermion systems and their theory. Further, experimental topics relevant to valence fluctuations are valuable resources for those who are new to the field to easily catch up with experimental background and facts.
Download or read book Quantum Critical Fluctuations in the Heavy Fermion Compound Ce Ni 0 935 Pd 0 065 2 Ge 2 written by and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In electric resistivity, specific heat, magnetic susceptibility, and inelastic neutron scattering experiments were performed on a single crystal of the heavy fermion compound Ce(Ni0.935Pd0.065)2Ge2 in order to study the spin fluctuations near an antiferromagnetic (AF) quantum critical point (QCP). The resistivity and the specific heat coefficient for T ≤ 1 K exhibit the power law behavior expected for a 3D itinerant AF QCP ([rho](T) ~ T3/2 and [gamma](T) ~ [gamma]0 - bT1/2). However, for 2 ≤ T ≤ 10 K, the susceptibility and specific heat vary as log T and the resistivity varies linearly with temperature. In spite of the fact that the resistivity and specific heat exhibit the non-Fermi liquid behavior expected at a QCP, the correlation length, correlation time, and staggered susceptibility of the spin fluctuations remain finite at low temperature. Here, we suggest that these deviations from the divergent behavior expected for a QCP may result from alloy disorder.
Download or read book Thermodynamic Characterization of Heavy Fermion Systems and Low Dimensional Quantum Magnets Near a Quantum Critical Point written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We report experimentally results on the low temperature properties of two classes of materials with a special emphasizes near the QCP induced by substitution and magnetic 1.field: (1) the HF systems YbRh2(Si0.95Ge0.05)2, Yb1-yLayRh2Si2 (y = 0.05, 0.1), and YbIr2Si2 with tetragonal structures and CeIn3-xSnx (x = 0.55, 0.6, 0.65, 0.7, 0.8) with cubic structure; (2) the quantum spin systems: Cs2CuCl4 and Cs2CoCl4. In all the HF compounds we have observed NFL behavior in zero magnetic field close to the QCP. The La substituted system does not show an antiferromagnetic (AFM) transition down to the lowest accessible temperature (0.03 K) while in YbRh2(Si1-xGex)2 with x = 0 and x = 0.05 AFM transitions occur at TN =0.07 K and 0.02 K, respectively. For Yb0.9La0.1Rh2Si2 we observe below 0.07 K saturation of DeltaC/T indicating clearly a LFL state for this concentration. For YbIr2Si2, DeltaC/T saturates below 0.5 K. In contrast to the Yb based compounds in the vicinity of the QCP, CeIn3-xSnx shows no evidence of a divergence in Delta C/T, with B or with x. Furthermore, we used specic heat measurements in the mK temperature range and at high fields (up to 12 T) to probe the phase diagrams in the low dimensional quantum antiferromagnets Cs2CuCl4 and Cs2CoCl4. In applied magnetic field, we have presented experimental evidence that in Cs2CuCl4 the field dependence of the critical temperature Tc(B) ~ (Bc-B)^1-Phi close to the critical field Bc = 8.51 T is well described with Phi=1.5. This is in very good agreement with the exponent expected in the mean-field approximation and support the notion of a Bose-Einstein condensation of magnons in Cs2CuCl4.
Download or read book Magnetism in Heavy Fermion Systems written by Harry Brian Radousky and published by World Scientific. This book was released on 2000 with total page 398 pages. Available in PDF, EPUB and Kindle. Book excerpt: Magnetism in Heavy Fermion Systems is a review volume which covers an important subset of topics in the field of heavy fermion and non-Fermi liquid physics. It summarizes much of the experimental information in these areas, and includes an article which discusses theoretical interpretations of the complex magnetic behavior of heavy fermion systems. The topics covered include heavy fermion superconductivity, muon spin relaxation in small-moment heavy fermions, neutron scattering from heavy fermions, random localized magnetism in heavy fermions, and magnetism in Pr-containing cuprates. One feature of the book which should be helpful to graduate students and new workers in the field is the extensive references and a separate list of review articles.
Download or read book Thermodynamic Characterization of Heavy Fermion Systems and Low Dimensional Quantum Magnets Near a Quantum Critical Point written by Maria Teodora Radu and published by . This book was released on 2005 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Journal of the Physical Society of Japan written by and published by . This book was released on 2016 with total page 934 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Competition and Unification of Kondo Coherence and Magnetic Ordering written by Saeed Saremi and published by . This book was released on 2009 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt: The heavy fermion quantum critical point is one of the most puzzling problems in the field of highly correlated electrons. This is a quantum critical point separating a non-magnetic heavy fermi liquid metal from an antiferromagnetically ordered metal. The major problem facing us is the fact that, based on new experiments, these two phases seem to collapse simultaneously at the quantum critical point, giving rise to a drastic change in the fermi surface across the transition. In the quest for a toy model to envision this simultaneous collapse, we study the Kondo-Heisenberg model on the honeycomb lattice at half-filling. We study a fixed point controlling the quantum phase transition of a Kondo coherent phase to a critical phase called algebraic spin liquid. Studying such a fixed point has been proposed to be key to understanding the quantum critical point in heavy fermions. The relativistic structure of the lowenergy theory is the hallmark of our theory. The critical theory, however, can only be managed by extending the spin flavors well beyond the physical up and down, a technique known as the "large-N expansion". We later approach the physical case of SU(2) spins head-on and propose a novel idea to unify the distinct Kondo coherent phase and antiferromagnetic phase. We propose destroying the Kondo phase by proliferating Kondo vortices. We show that spin-triplets can be created by a Kondo vortex because of the zero modes it generates at the chemical potential. This gives us a nice picture that a magnetic transition can be driven by proliferating Kondo vortices. We also identify a class of these spin-triplets that transform like a Néel order. Due to the half-filled limitation of this model, however, this Kondo-vortexdriven antiferromagentic transition is in the O(3) universality class. We also prove that, starting from the pure Kondo lattice model, due to the charge-conjugation symmetry, antiferromagentic Heisenberg exchange will be generated, and the pure Kondo lattice model transforms to the Kondo-Heisenberg model we have studied. A major asset of the model we have studied is that it can be simulated using a signfree quantum Monte Carlo method, and our analytical results can all be probed in numerics. We present our preliminary numerical results for this model.
Download or read book Exploring Heavy Fermion Materials Near a Quantum Critical Point written by Sooyoung Jang and published by . This book was released on 2015 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt: Results for two categories of heavy fermion systems : (1) a new type of non-centrosymmetric heavy fermion system R2TM12Pn7 (R = rare earth, TM = transition metal, Pn = P, As), and (2) Yb substitution in CeCoIn5, which is a heavy fermion superconductor, Ce1-xYbxCoIn5, are described. The phenomena seen in the system R2TM12Pn7 are discussed in terms of strong hybridization between the localized f-electron states and the conduction electron states, such as a crossover between Fermi liquid and non-Fermi liquid behavior in Yb2Ni12P7, or the presence of a large value of the Sommerfeld coefficient, [gamma] ~ 650 mJ/mol Sm K2 in Sm2Ni12P7. The extraordinary electronic phenomena found in the system Ce1-xYbxCoIn5 include Yb valence fluctuations, a change in the Fermi surface topology, and suppression of the quantum critical field occurring at a nominal concentration of x ~ 0.2. However, the suppression of the superconducting critical temperature with nominal Yb concentration x for bulk single crystals is much weaker than that observed in thin film samples. The actual Yb composition of bulk single crystals is found to be about 1/3 of the nominal concentration, resolving the discrepancy between the variation of the physical properties of Ce1-xYbxCoIn5 single crystals and thin films with Yb concentrations.
Download or read book Rare Earths and Actinides in High Energy Spectroscopy written by Christiane Bonnelle and published by Springer. This book was released on 2015-12-22 with total page 393 pages. Available in PDF, EPUB and Kindle. Book excerpt: This unique monograph covers recent theoretical and experimental results on the complex character of f electrons in materials containing lanthanides (rare earths) or actinides, such as alpha-cerium and delta-plutonium. It answers the urgent need for a general presentation of the body of experimental and theoretical results presently available in this challenging domain. Some of the fast developing applications of lanthanide and actinide materials are mentioned. Materials containing atoms with an open f shell have electronic and crystalline properties that are controlled by the localized or delocalized character of the f electrons. This book gives a theoretical discussion of the various spectroscopic methods that shed light on the character of the f electrons and on the connection between their localization and the properties of these materials. Part 1 covers the characteristics of the f electrons in atoms and solids and includes a discussion of the properties of lanthanides and actinides in connection with the f electrons. Part 2 describes the various spectroscopic methods that are used to establish the electronic distributions and energies of the states. Examples involve the determination of f electron distributions by high energy spectroscopy methods with separate treatment of the valence and core electrons. Part 3 concentrates on the theoretical treatment of electronic transitions involving f electrons and simulations of the lanthanide spectra, including comparison with the available experimental data. Part 4 discusses the localized or delocalized character of the f electrons in actinides and their compounds, including comparison (analogies & differences) between the 4f and 5f electron materials. This monograph should be of great value for researchers, academics and engineers working in the fields of high energy spectroscopy, electronic and nuclear science and technology, as well as materials involving rare earths and radio-elements.
Download or read book Handbook on the Physics and Chemistry of Rare Earths written by and published by Elsevier. This book was released on 2016-08-01 with total page 482 pages. Available in PDF, EPUB and Kindle. Book excerpt: Handbook on the Physics and Chemistry of Rare Earths is a continuous series of books covering all aspects of rare earth science, including chemistry, life sciences, materials science, and physics. The book's main emphasis is on rare earth elements [Sc, Y, and the lanthanides (La through Lu], but whenever relevant, information is also included on the closely related actinide elements. Individual chapters are comprehensive, broad, up-to-date critical reviews written by highly experienced, invited experts. The series, which was started in 1978 by Professor Karl A. Gschneidner Jr., combines and integrates both the fundamentals and applications of these elements and publishes two volumes a year. Presents up-to-date overviews of new developments in the field of rare earths, covering both their physics and chemistry Contains Individual chapters that are comprehensive and broad, with critical reviews Provides contributions from highly experienced, invited experts
Download or read book Proceedings of the International Symposium on Topological Aspects of Critical Systems and Networks Sapporo Japan 13 14 February 2006 written by Kousuke Yakubo and published by World Scientific. This book was released on 2007 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume gives an interdisciplinary discussion on the topological aspects of general networks and critical systems for physicists, chemists, biologists, mathematicians, medical scientists, social scientists, and other related researchers. Subjects as diverse as the general properties of complex networks, complexity in social science, patterns in biological objects, and criticality in pure and applied physics are represented. The book is essential for researchers in a wide range of scientific and technological fields related to these areas.
Download or read book Novel Magnetic States in the Heavy Fermion Quantum Critical Material CeRhIn5 at High Magnetic Fields Studied by NMR written by and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Role of Fluctuations Near Antiferromagnetic and Spin triplet Nematic Quantum Critical Points written by Gregor Maximilian Hannappel and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Room temperature Superconductivity written by Andrei Mourachkine and published by Cambridge Int Science Publishing. This book was released on 2004 with total page 326 pages. Available in PDF, EPUB and Kindle. Book excerpt: Annotation The first book dealing with the subject of room-temperature conductivity.
Download or read book The Role of Fluctuations Near Antiferromagnetic and Spin triplet Nematic Quantum Critical Points written by G. Hannappel and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
