X Ray And Neutron Scattering Studies Of Magnetic Domain Dynamics And Spin Structures

The study of magnetic spin structures at nanometer length scales and their dynamics is of both fundamental and technological importance. X-rays and neutrons are penetrating probes that are suitable for studying these in the bulk and the interfaces of the materials. In this thesis, the magnetic domain dynamics are studied by resonant soft x-ray scattering together with x-ray photon correlation spectroscopy. The domain fluctuations reveal when the temperature is close to the phase transition temperature. We find the domain wall dynamics in an antiferromagnet corresponds to a collective motion of spins and exhibit some universal features associated with the jamming behavior in many jammed soft condensed matter systems. We also discuss about the utilization of polarized neutron reflectometry to study the interfacial spin structure in an exchange biased bilayer. The magnetization profiles are obtained which show that some spins are not completely reversible when the magnetic field is reversed. These spins include pinned uncompensated spins in the antiferromagnet and the interfacial spins exchange coupled to those spins. A previously established model was found to reproduce the magnetization profile observed. Finally, we carried out a grazing incidence small angle neutron scattering experiment on an optical grating as a way to test the Distorted Wave Born Approximation (DWBA). DWBA is briefly reviewed and we used it to calculate the scattering intensity of the system.

The proceedings provide a topical survey of the static and dynamical magnetic properties of condensed matter studied by neutron scattering which has been the key technique in this field for a long time. The static aspects deal with the determination of long-range ordered spin structures and magnetization densities. The dynamic aspects concentrate on the determination of magnetic excitations such as spin waves and crystal-field transitions. The use of polarized-neutron techniques is particularly emphasized. All these topics are thoroughly introduced, methodically discussed, and highlighted with recent experimental results obtained for a vast variety of magnetic materials (e.g., strongly correlated electron systems, multilayers, nanocrystals, molecular complexes, etc.) by acknowledged experts. Other experimental methods (x-ray scattering, muon spin rotation) in the study of magnetism are compared to neutron scattering.

Modern Techniques for Characterizing Magnetic Materials provides an extensive overview of novel characterization tools for magnetic materials including neutron, photon and electron scatterings and other microscopy techniques by world-renowned scientists. This interdisciplinary reference describes all available techniques to characterize and to understand magnetic materials, techniques that cover a wide range of length scales and belong to different scientific communities. The diverse contributions enhance cross-discipline communication, while also identifying both the drawbacks and advantages of different techniques, which can result in deriving effective combinations of techniques that are especially fruitful at nanometer scales. It will be a valuable resource for all graduate students, researchers, engineers and scientists who are interested in magnetic materials including their crystal structure, electronic structure, magnetization dynamics and their associated magnetic properties and underlying magnetism.

Neutron Scattering from Magnetic Materials is a comprehensive account of the present state of the art in the use of the neutron scattering for the study of magnetic materials. The chapters have been written by well-known researchers who are at the forefront of this field and have contributed directly to the development of the techniques described. Neutron scattering probes magnetic phenomena directly. The generalized magnetic susceptibility, which can be expressed as a function of wave vector and energy, contains all the information there is to know about the statics and dynamics of a magnetic system and this quantity is directly related to the neutron scattering cross section. Polarized neutron scattering techniques raise the sophistication of measurements to even greater levels and gives additional information in many cases. The present book is largely devoted to the application of polarized neutron scattering to the study of magnetic materials. It will be of particular interest to graduate students and researchers who plan to investigate magnetic materials using neutron scattering. · Written by a group of scientist who have contributed directly in developing the techniques described.· A complete treatment of the polarized neutron scattering not available in literature.· Gives practical hits to solve magnetic structure and determine exchange interactions in magnetic solids.· Application of neutron scattering to the study of the novel electronic materials.

Neutron Scattering - Magnetic and Quantum Phenomena provides detailed coverage of the application of neutron scattering in condensed matter research. The book's primary aim is to enable researchers in a particular area to identify the aspects of their work where neutron scattering techniques might contribute, conceive the important experiments to be done, assess what is required to carry them out, write a successful proposal for one of the major user facilities, and perform the experiments under the guidance of the appropriate instrument scientist. An earlier series edited by Kurt Sköld and David L. Price, and published in the 1980s by Academic Press as three volumes in the series Methods of Experimental Physics, was very successful and remained the standard reference in the field for several years. This present work has similar goals, taking into account the advances in experimental techniques over the past quarter-century, for example, neutron reflectivity and spin-echo spectroscopy, and techniques for probing the dynamics of complex materials of technological relevance. This volume complements Price and Fernandez-Alonso (Eds.), Neutron Scattering - Fundamentals published in November 2013. Covers the application of neutron scattering techniques in the study of quantum and magnetic phenomena, including superconductivity, multiferroics, and nanomagnetism Presents up-to-date reviews of recent results, aimed at enabling the reader to identify new opportunities and plan neutron scattering experiments in their own field Provides a good balance between theory and experimental techniques Provides a complement to Price and Fernandez-Alonso (Eds.), Neutron Scattering - Fundamentals published in November 2013

Understanding and manipulating the properties of materials naturally occurring in our world and artificially produced by modern technologies requires detailed information on their properties on the atomic scale. This information is the basis for any kind of research in physics, chemistry, biology, engineering, metallurgy, and ceramics. Among the various experimental methods, neutron and photon scattering have become the key techniques of choice.This book provides an overview of the complementarity between neutron and synchrotron x-ray scattering. The most important topics are covered, including structure determination, magnetic correlations, polymer dynamics, thin films and multilayers, photoemission studies, etc; they are thoroughly introduced and discussed by experts from both the experimental and the theoretical side.

This research monograph presents the latest results related to the characterization of low dimensional systems. Low-angle polarized neutron scattering and X-ray scattering at grazing incidence are used as the two main techniques to explore various physical phenomena of these systems. Special focus is put on systems like thin film transition metal and rare-earth layers, oxide heterostructures, hybrid systems, self-assembled nanostructures and self-diffusion. Readers will gain in-depth knowledge about the usage of specular scattering and off-specular scattering techniques. Investigation of in-plane and out-of-plane structures and magnetism with vector magnetometric information is illustrated comprehensively. The book caters to a wide audience working in the field of nano-dimensional magnetic systems and the neutron and X-ray reflectometry community in particular.

Magnetic Small-Angle Neutron Scattering provides the first extensive treatment of magnetic small-angle neutron scattering (SANS). The theoretical background required to compute magnetic SANS cross sections and correlation functions related to long-wavelength magnetization structures is laidout. The concepts are scrutinized based on the discussion of experimental neutron data. Regarding prior background knowledge, some familiarity with the basic magnetic interactions and phenomena as well as scattering theory is desired.Besides exposing the different origins of magnetic SANS, and furnishing the basics of the magnetic SANS technique in early chapters, a large part of the book is devoted to a comprehensive treatment of the continuum theory of micromagnetics, as it is relevant for the study of the elastic magneticSANS cross section. Analytical expressions for the magnetization Fourier components allow to highlight the essential features of magnetic SANS and to analyze experimental data both in reciprocal, as well as in real space. Later chapters provide an overview on the magnetic SANS of nanoparticles andso-called complex systems (e.g., ferrofluids, magnetic steels, spin glasses and amorphous magnets). It is this subfield where major progress is expected to be made in the coming years, mainly via the increased usage of numerical micromagnetic simulations (Chapter 7), which is a very promisingapproach for the understanding of the magnetic SANS from systems exhibiting nanoscale spin inhomogeneity.