Author: David MacdougalPublisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Neutron Scattering Studies of Low-dimensional Quantum Magnets
Author: David MacdougalNeutron Scattering Studies on Low-dimensional Quantum Magnets
Author: Chiron Jeeb MukherjeePublisher:
ISBN:
Category : Antiferromagnetism
Languages : en
Pages : 418
Book Description
Neutron and Resonant X-ray Scattering Studies of Low Dimensional Quantum Magnets
Author: Neutron Scattering from Low-dimensional Quantum Magnets
Author: Elisa Maria da Silva WheelerPublisher:
ISBN:
Category : Antiferromagnetism
Languages : en
Pages : 0
Book Description
Neutron Scattering Studies of Low-dimensional Quantum Spin Systems
Author: Nikolay TsyrulinNeutron Scattering Studies of Low-dimensional Quantum Spin Systems
Author: Stefan Paul GosulyNeutron Scattering Studies of Low-dimensional Quantum Spin Systems
Author: S. P. GosulyNeutron Scattering Investigations of Zero- and One-dimensional Quantum Magnets
Author: Oliver PieperPublisher:
ISBN: 9783832527303
Category :
Languages : en
Pages : 270
Book Description
This thesis deals with the investigation of two different types of low-dimensional quantum magnets using the technique of neutron scattering.In the first part, the magnetic properties of three Mn_6-based single molecule magnets are explored by means of inelastic neutron scattering. The experimental data reveal that small structural distortions of the molecular geometry produce a significant effect on the energy level diagram and therefore on the magnetic properties of the molecules. It will be shown that the giant spin model completely fails to describe the spin level structure of the ground spin multiplets and that the excited S-multiplets play a key role in determining the effective energy barrier for the magnetization reversal.The second part of this thesis presents an in-depth study of the nuclear and magnetic properties of the quasi-one-dimensional Heisenberg antiferromagnet CaV_2O_4. The magnetism in this system arises from the partially filled t_{2g-levels of the V^{3+-ions, which in addition give an orbital degree of freedom to the system.Single crystal and powder neutron diffraction as well as neutron spectroscopy are used to determine the nuclear and magnetic structure as well as the complex excitation spectrum of CaV_2O_4. The results are analysed theoretically and from this the leading exchange paths are deduced and discussed in terms of orbital ordering.
INTERACTING QUANTUM SPIN CHAINS.
Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
A brief review of recent advances in neutron scattering studies of low-dimensional quantum magnets is followed by a particular example. The separation of single-particle and continuum states in the weakly-coupled S = l/2 chains system BaCu2Si2O-- is described in some detail.
Scattering Studies of Magnetic and Charge Correlations in Two-dimensional Quantum Magnets
Author: Wei He (Researcher in materials science)Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
The study of quantum magnets in two-dimensional systems is a forefront field in both materials science and condensed matter physics research. Such materials not only provide rich platforms for potential applications of novel materials but also further our understanding of basic physics. Neutron and x-ray scattering are powerful tools to explore the magnetic and charge correlations in these materials. This thesis describes the experimental investigation of two model systems in bulk crystalline form, one with a two-dimensional kagome lattice and one with a two-dimensional square lattice, both consisting of Cu2+ ions with spin-1/2. Strong quantum fluctuations give competing ground states or phases in both systems. Recently, barlowite Cu4(OH)6FBr has attracted much attention as the parent compound of a new kagome quantum spin liquid candidate. Our new synthesis method produced large single crystals of a new variant of barlowite, which has a higher symmetry space group compared to the previously reported one. Our elastic magnetic neutron scattering measurements reveal that the magnetic ground state of the new high-symmetry barlowite at low temperatures has a special pinwheel q = 0 magnetic order. In the intermediate temperatures, our numerical calculations and inelastic neutron scattering indicate that the kagome spins are in a potential pinwheel valence bond crystal state. Both of the two ground states are in close proximity to the long-sought quantum spin liquid state. The second part of my thesis is focused on the spin and charge correlations in high-Tc cuprate superconductors. Cuprate materials display intriguing physical phenomena due to the coexistence of various phases, which may interact with the superconductivity. The La-based family is a canonical example where both the spin and charge correlations could form "stripes". Magnetic neutron scattering reveals a rather surprising feature of the spin stripes in the model material La1.88Sr0.12CuO4: regardless of whether they are static or fluctuating, these stripes are always tilted from the high-symmetry direction of underlying lattices. Comparison with numerical simulations reveals the important role of the next-nearest neighbor electron hopping. Resonant soft x-ray scattering measurements offer important information about the charge order in another cuprate material stage-6 O-doped La2CuO4+y. By tuning both temperature and the dopant disorder level, we clearly observe two types of charge orders with distinct correlation lengths and behaviors at low temperatures. A coherent picture based on microscopic phase separation is proposed to explain the relationship between charge and spin orders with superconductivity in these materials.