Magnetic Excitations and Fluctuations II

An international workshop on Elementary Excitations and Fluctuations in Magnetic Systems was held in Turin for five days beginning 25 May, 1987. The workshop followed much the same format as the one with the same title held in San Miniato in 1984 (proceedings: Springer Series in-Solid-State Sciences, Vol. 54), that most participants contributed talks and provided papers for the proceedings. While many of the participants had attended the first workshop, 15 of the 40 invited review papers were presented by scientists who had not. The majority of the talks reported theoretical work concerned with the introduction of new techniques. However, experimental work was also well represented, not least because many of the reported theoretical studies were motivated by experimental findings, and a highlight of the workshop was an extremely stimulating session devoted to recent neutron scattering measure ments, on various systems, that exploited polarization analysis. The fine venue of the workshop, Villa Gualino, with its excellent facili ties and spacious accommodation, helped to produce a delightful relaxed and friendly atmosphere. For the use of Villa Gualino and significant financial support we are indebted to our host organization, the Institute for Scien tific Interchange (lSI). Additional financial support came from the Consiglio Nazionale delle Ricerche (CNR), Centro Interuniversitario di Struttura della Material del Ministero della Pubblica Istruzione (CISM-MPI) and Gruppo Nazionale di Struttura della Materia (GNSM-CNR).

Inhalt
I Statistical Mechanics and Mathematical Physics.- Statistical Mechanics of the Integrable Models.- Lattice Equations, Hierarchies and Hamiltonian Structures.- Modular Invariance and Two-Dimensional Critical Systems.- Variational Principle for Quantum Effects on Nearly Sine-Gordon Chains.- Quantum Theory of Planar Kinks in a Finite Easy Plane Ferromagnetic Chain.- RAF Model and Solid Oxygen: Infinite Degeneracy, Soft Lines, No LRO in Classical Approximation and Order by Quantum Disorder.- Phase Transitions in Ising Superlattices.- A Fermionic Treatment of the Frustrated Ising Model.- Calculation of Static Magnetic Susceptibilities of a Jahn-Teller E-Doublet.- II Random Field Problems, Spin Glasses and Chaotic Behaviour.- Critical Properties of the Random Field Ising Model.- Random-Exchange and Random-Field xy-Chain for 5=1/2.- Spin-glass-like Behaviour in Spinels.- Harmonic Magnons in Spin Glasses: Cd0.35Mn0.65Te.- On a Symmetric (2S+l)-State System Coupled to Its Environment: Tunneling Splitting and Quantum Coherence.- Regular and Chaotic Dynamics of Classical Spin Systems.- The Kicked Quantum Spin: A Model System for Quantum Chaos.- Chaotic Dynamics of Spin Wave Instabilities.- III Theory of Spin Excitations.- Spin 1 vs Spin ½ Antiferromagnetic Chains: The Staggered Magnetization.- Excitations and Critical Behavior in Generalized Heisenberg Spin Chains.- Exact Results for the Out of Plane Dynamical Correlation Function in a Classical Easy Plane Ferromagnet at Low Temperatures.- A Comparison of the Bethe Ansatz and Green Function Approaches to Two-Magnon States of the Ferromagnetic Chain.- Nonlinear Effects in Low-Dimensional Magnetism: Solitons and Vortices.- Theory of Excitations in Incommensurably Modulated Magnets.- Linear Spin Dynamics of IncommensurablyModulated Magnets: Numerical and Analytic Results.- On the Interpretation of Electronic and Phonon Anomalies in Mixed Valence Compounds.- Bloch Lines as Magnetic Excitations in Domain Wall Dynamics with a Large Sensitivity to Initial Conditions.- Dynamics of Magnetic Domain Walls and Barkhausen Noise in Metallic Ferromagnetic Systems.- IV Spin Excitations: Experiments and Computer Simulations.- Magnetic Fluctuations and Excitations in the S=1 Antiferromagnetic Chains of NENP.- Study of Longitudinal Fluctuations in CsNiF3 by Means of Inelastic Polarized Neutron Scattering.- Dynamics of Critical Fluctuations in Isotropic Ferromagnets: Current Problems.- Magnetism of MnSi and FeSi.- Neutron Scattering from Heavy Fermion Systems.- Linear and Nonlinear Excitations in the S=1/2 Ferromagnetic Chain System [C6H11NH3]CuBr3 (CHAB).- Doublings of Soliton Modes and Soliton Magnetic Resonance (SMR).- Relaxation Phenomena in Non-linear Systems; A Mössbauer Effect Spectroscopy and Susceptibility Study.- A Raman Scattering Study of the Spin-Phonon Interaction in Rutile Structure Antiferromagnets.- Raman Scattering Studies of Optical Magnons and of High-Energy Magnetic Excitons.- Spin-Dynamics Studies of Excitations in xy-Chains.- Numerical Transfer-Kernel Results for the Classical xy-Chain in a Magnetic Field.- Monte Carlo Simulation of the Quantum Sine-Gordon Chain.- Index of Contributors.