Author: Verena Sabine KarglPublisher:
ISBN:
Category :
Languages : en
Pages : 123
Book Description
Magnetic Properties of Low Dimensional Spin Systems
Author: Verena Sabine KarglSynthesis, Structure and Magnetic Properties of Low Dimensional Spin Systems in the 3d Transition Metal Oxides and Superconductivity in MgB2
Author: Nyrissa S. RogadoMagnetoelectric Response in Low-Dimensional Frustrated Spin Systems
Author: Shinichiro SekiPublisher: Springer Science & Business Media
ISBN: 4431540911
Category : Science
Languages : en
Pages : 135
Book Description
Electric control of magnetic properties, or inversely, magnetic control of dielectric properties in solids, is called a magnetoelectric effect and has long been investigated from the point of view of both fundamental physics and potential application. Magnetic and dielectric properties usually show minimal coupling, but it recently has been discovered that magnetically induced ferroelectricity in some spiral magnets enables remarkably large and versatile magnetoelectric responses. To stabilize such helimagnetism, magnetic frustration (competition between different magnetic interactions) is considered the key. In the present work, two of the most typical frustrated spin systems—triangular lattice antiferromagnets and edge-shared chain magnets—have systematically been investigated. Despite the crystallographic simplicity of target systems, rich magnetoelectric responses are ubiquitously observed. The current results published here offer a useful guideline in the search for new materials with unique magnetoelectric functions, and also provide an important basis for a deeper understanding of magnetoelectric phenomena in more complex systems.
Magnetic Properties of Low Dimensional Systems
Author: Static and Dynamic Properties of low dimensional Quantum Spin Systems
Author: Simon Nils GrossjohannPublisher: Cuvillier Verlag
ISBN: 373693419X
Category : Science
Languages : en
Pages : 168
Book Description
In my thesis, static and dynamic properties of low-dimensional spin models were studied by means of a state of the art QMC method (SSE). As one among many numerical algorithms (e.g. DMRG, ED), the QMC proved to be a very flexible and high performance tool with access to dynamic correlation functions at finite temperatures and finite magnetic fields within the thermodynamic limit1. After detailed introduction of the QMC’s basic implementation, I provided yet unpublished information about the measurement of transverse (and longitudinal) imaginary time correlation functions for the spin S Heisenberg model. In addition to that, complications of the analytic continuation to the real axis were explained and two common Maximum Entropy algorithms (Bryan and Meshkov) introduced briefly. In my thesis, both algorithms have been implemented and contrasted in regard to their performance and quality of the continuation, clearly favoring Bryan’s method which is a standard least square algorithm based on Newton iterations with however highly optimized search directions in the multi-dimensional solution space.
Magnetic Properties of Low-dimensional Systems II
Author: Leopoldo Maximo FalicovPublisher: Berlin ; New York : Springer-Verlag
ISBN:
Category : Science
Languages : en
Pages : 268
Book Description
Experimental Investigation of New Low-Dimensional Spin Systems in Vanadium Oxides
Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
In this dissertation we reported our experimental investigation of the magnetic properties of nine low-dimensional vanadium compounds. Two of these materials are completely new (Pb2V5O12 and Pb2VO(PO4)2) and were found during our search for new low-dimensional vanadium oxides. Among the other seven vanadium compounds studied, three were physically investigated for the first time (Sr2VO(PO4)2, BaZnVO(PO4)2 and SrZnVO(PO4)2). Two had hitherto only preliminary, and wrongly interpreted, susceptibility measurements reported in the literature (Sr2V3O9 and Ba2V3O9) while the remaining two (Li2VOSiO4 and Li2VOGeO4) were previously investigated in some detail but the interpretation of the data was controversial. We investigated the magnetic properties of these materials by means of magnetic susceptibility and specific heat (Cp(T)) measurements (as well as single crystal ESR measurements in the case of Sr2V3O9). We synthesized the samples necessary for our physical studies. That required a search of the optimal synthesis conditions for obtaining pure, high quality, polycrystalline samples. Single crystals of Sr2V3O9 and Pb2VO(PO4)2 were also successfully grown. Pb2VO(PO4)2, BaZnVO(PO4)2, SrZnVO(PO4)2, Li2VOSiO4 and Li2VOGeO4 were found to be experimental examples of frustrated square-lattice systems which are described by the J1-J2 model. We found that Li2VOSiO4 and Li2VOGeO4 posses a weakly frustrated antiferromagnetic square lattice while Pb2VO(PO4)2, BaZnVO(PO4)2 and SrZnVO(PO4)2 form a more strongly frustrated ferromagnetic square lattice. Pb2V5O12 is structurally and compositionally related to the two dimensional A2+V4+nO2n+1 vanadates. Its structure consists of layers formed by edge- and corner-shared square VO5 pyramids. The basic structural units are plaquettes consisting of six corner-shared pyramids pointing in the same direction, which form a spin lattice of novel geometry.
Magnetic Field Effects in Low-Dimensional Quantum Magnets
Author: Adam IaizziPublisher: Springer
ISBN: 3030018032
Category : Science
Languages : en
Pages : 156
Book Description
This thesis is a tour-de-force combination of analytic and computational results clarifying and resolving important questions about the nature of quantum phase transitions in one- and two-dimensional magnetic systems. The author presents a comprehensive study of a low-dimensional spin-half quantum antiferromagnet (the J-Q model) in the presence of a magnetic field in both one and two dimensions, demonstrating the causes of metamagnetism in such systems and providing direct evidence of fractionalized excitations near the deconfined quantum critical point. In addition to describing significant new research results, this thesis also provides the non-expert with a clear understanding of the nature and importance of computational physics and its role in condensed matter physics as well as the nature of phase transitions, both classical and quantum. It also contains an elegant and detailed but accessible summary of the methods used in the thesis—exact diagonalization, Monte Carlo, quantum Monte Carlo and the stochastic series expansion—that will serve as a valuable pedagogical introduction to students beginning in this field.
Physics of Low Dimensional Systems
Author: J.L. Morán-LópezPublisher: Springer Science & Business Media
ISBN: 0306471116
Category : Science
Languages : en
Pages : 465
Book Description
Oaxaca, Mexico, was the place chosen by a large international group of scientists to meet and discuss on the recent advances on the understanding of the physical prop- ties of low dimensional systems; one of the most active fields of research in condensed matter in the last years. The International Symposium on the Physics of Low Dim- sions took place in January 16-20, 2000. The group of scientists converging into the historical city of Oaxaca, in the state of the same name, had come from Argentina, Chile, Venezuela, several places in Mexico, Canada, U. S. A. , England, France, Italy, Germany, Russia, and Switzerland. The presentations at the workshop provided sta- of-art reviews of many of the most important problems, currently under study. Equally important to all the participants in the workshop was the fact that we had come to honor a friend, Hans Christoph Siegmann, on his sixty-fifth birthday. This Festschrift recognizes the intellectual leadership of Professor Siegmann in the field and as a sincere homage to his qualities as an exceptional friend, college and mentor. Those who have had the privilege to work closely with Hans Christoph have been deeply impressed by his remarkable analytic mind as well as by his out of range kindness and generosity. Hans Christoph has contributed to the understanding of the difficult and very important problem of the magnetic properties of finite systems: surfaces, thin films, heterostructures.
Magnetic Properties of Low-dimensional Systems II
Author: Leopoldo Maximo FalicovPublisher: Berlin ; New York : Springer-Verlag
ISBN:
Category : Science
Languages : en
Pages : 268
Book Description