Spin-Wave Theory and Its Applications to Neutron Scattering and THz Spectroscopy
- Randy S Fishman, Jaime A Fernandez-Baca, Toomas Rõõm
- November 2018
DescriptionTwo of the most powerful tools used to study magnetic materials are inelastic neutron scattering and THz spectroscopy. Because the measured spectra provide a dynamical fingerprint of a magnetic material, these tools enable scientists to unravel the structure of complex magnetic states and to determine the microcscopic interactions that produce them. This book discusses the experimental techniques of inelastic neutron scattering and THz spectroscopy and provides the theoretical tools required to analyze their measurements using spin-wave theory. For most materials, this analysis can resolve the microscopic magnetic interactions such as exchange, anisotropy and Dzyalloshinskii–Moriya interactions. Assuming a background in elementary statistical mechanics and a familiarity with the quantized harmonic oscillator, this work presents a comprehensive review of spin-wave theory and its applications to both inelastic neutron scattering and THz spectroscopy. Spin-wave theory is used to study several model magnetic systems, including non-collinear magnets such as spirals and cycloids that are produced by geometric frustration, competing exchange interactions, or Dzyalloshinskii–Moirya interactions. Several case studies utilizing spin-wave theory to analyze inelastic neutron scattering and THz spectroscopy measurements are presented. These include both single crystals and powders, and both oxides and molecule-based magnets. In addition to sketching the numerical techniques used to fit dynamical spectra based on microscopic models, this book also contains more than 70 exercises that can be performed by beginning graduate students.
Randy Fishman was a former leader of the Materials Theory Group and is currently a distinguished R&D staff scientist at ORNL. As a condensed-matter theorist, he studies the complex magnetic states of oxides and molecule-based magnets, frequently in collaboration with neutron scientists and optical spectroscopists. Fishman is the author of more than 160 scientific publications.
Dr Jaime A Fernandez-Baca is a distinguished research staff member in ORNL's quantum condensed matter division, and the leader of the Triple Axis Spectroscopy Group at the High Flux Isotope Reactor. Fernandez-Baca's expertise is in the study of the magnetic ordering and spin dynamics of complex oxides and related alloys utilizing neutron scattering techniques.
Toomas Rõõm is currently a research professor at the National Institute of Chemical Physics and Biophysics in Tallinn, Estonia. His research interest is in combining infrared and terahertz spectroscopy with high magnetic fields and low temperatures for studies of magnetic and correlated electron materials. In 2016, he received a state award for "Interaction of terahertz radiation with materials" with his colleague Dr U Nagel.
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Paperback ISBN: 9780750329576
Ebook ISBN: 9781643271132
Publisher: Morgan & Claypool Publishers