Table Of Content23
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Procee
Managing Editor: H. K. V. Lotsch
Volume 1 Fluctuations and Sensitivity in Nonequilibrium Systems
Editors: W. Horsthemke and D. K Kondepudi
Volume 2 EXAFS and Near Edge Structure 11/
Editors: K O. Hodgson, B. Hedman, and J. E. Penner-Hahn
Volume 3 Nonlinear Phenomena in Physics Editor: F. Claro
Volume 4 Time-Resolved Vibrational Spectroscopy
Editors: A. Laubereau and M. Stockburger
Volume 5 Physics of Finely Divided Matter Editors: N. Boeeara and M. Daoud
Volume 6 Aerogels Editor: J. Fricke
Volume 7 Nonlinear Optics: Materials and Devices Editors: C. Flytzanis and J. L. Oudar
Volume 8 Optical Bistability 11/ Editors: H. M. Gibbs, P. Mandel,
N.Peyghambarian, and S.D.Smith
Volume 9 Ion Formation from Organic Solids (IFOS 11/) Editor: A. Benninghoven
Volume 10 Atomic Transport and Defects in Metals by Neutron Scattering
Editors: C.Janot, W.Petry, D.Riehter, and T.Springer
Volume 11 Biophysical Effects of Steady Magnetic Fields
Editors: G. Maret, J. Kiepenheuer, and N. Boeeara
Volume 12 Quantum Optics IV Editors: J. D. Harvey and D. F. Walls
Volume 13 The Physics and Fabrication of Microstructures and Microdevices
Editors: M.J. Kelly and C. Weisbueh
Volume 14 Magnetic Properties of Low-Dimensional Systems
Editors: L. M. Falieov and J. L. Moran-L6pez
Volume 15 Gas Flow and Chemical Lasers Editor: S. Rosenwaks
Volume 16 Photons and Continuum States of Atoms and Molecules
Editors: N.KRahman, C.Guidotti, and M.Allegrini
Volume 17 Quantum Aspects of Molecular Motions in Solids
Editors: A Heidemann, A Magerl, M.Prager, D.Riehter, and T.Springer
Volume 18 Electro-optic and Photorefractive Materials Editor: P. GOnter
Volume 19 Lasers and Synergetics Editors: R. Graham and A. Wunderlin
Volume 20 Primary Processes in Photobiology Editor: T. Kobayashi
Volume 21 Physics of Amphiphilic Layers Editors: J. Meunier, D. Langevin,
and N. Boeeara
Volume 22 Semiconductor Interfaces: Formation and Properties
Editors: G. Le Lay, J. Derrien, and N. Boeeara
Volume 23 Magnetic Excitations and Fluctuations 1/ Editors: U. Balueani, S. W. Lovesey,
M.G. Rasetti, and V. Tognetti
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Magnetic Excitations
and Fluctuations II
Proceedings of an International Workshop,
Turin, Italy, May 25 - 30, 1987
Editors: U. Balucani, S. W Lovesey,
M. G. Rasetti, and V. Tognetti
With 96 Figures
Springer-Verlag Berlin Heidelberg New York
London Paris Tokyo
Dr. Umberto Balucani
Istituto di Elettronica, Quantistica, CNR, via Panciatichi 56/30.
1-50127 Firenze, Italy
w.
Professor Stephen Lovesey
Rutherford Appleton Lab., Chilton, Oxfordshire, OX 11 OQX, U.K.
Professor Mario G. Rasetti
Dipartimento di Fisica Politecnico di Torino, Corso Duca degli Abruzzi, 24, 1-10129 Torino, Italy
Professor Valerio Tognetti
Dipartimento di Fisica, Universita di Firenze, Largo E. Fermi, 1-50125 Firenze, Italy
ISBN-13: 978-3-642-73109-9 e-ISBN-13: 978-3-642-73107-5
001: 10.1007/978-3-642-73107-5
Library of Congress Cataloging-in-Publication Data. Magnetic excitations and fluctuations II: pro
ceedings of an international workshop, Turin, Italy, May 25-30, 1987 / editors, U. Balucani ... let al.l.
(Springer proceedings in physics; v. 23) Sponsored by the Institute for Scientific Interchange (lSI) In
cludes index. 1. Statistical mechanics - Congresses. 2. Mathematical physics - Congresses. 3. Spin
excitations - Congresses. I. Balucani, U. (Umberto), 1942-. II. Institute for Scientific Interchange.
III. Series. QC174.7M34 1987 539.7'2-dc19 87-28852
This work is subject to copyright. All rights are reserved, whether the whole or part of the material is
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thereof is only permitted under the provisions of the German Copyright Law of September 9, 1965, in its
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the German Copyright Law.
© Springer-Verlag Berlin Heidelberg 1987
Softcover reprint of the hardcover 1s t edition 1987
The use of registered names, trademarks, etc. in this publication does not imply, even in the absence of a
specific statement, that such names are exempt from the relevant protective laws and regulations and there
fore free for general use.
2153/3150-543210
Preface
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).
The permanent staff of the lSI, Tiziana Bertoletti (Coordinator) and Car
men Novella (Secretary) took on the lion's share of the administration and
organization of the workshop. Preparation of the proceedings for publica
tion was competently and swiftly handled by Carla Pardini (Florence). The
creature comforts of good food, a good bar service and well-prepared ac
commodation were provided, with much charm, by Lina De Nisco and her
helpers.
Finally, we thank all the participants for their attendance and spirited
individual contributions to the success of the workshop.
Turin, June 1987 U. BaJucam S. W. Lovesey
M. Rasetti V. Tognetti
v
Contents
Part I Statistical Mechanics and Mathematical Physics
Statistical Mechanics of the Integrable Models
By R.K. Bullough, D.J. Pilling, and J. Timonen 2
Lattice Equations, Hierarchies and Hamiltonian Structures
By H. W. Capel and G.L. Wiersma ............ . . . . . . . . . . . . . 6
Modular Invariance and Two-Dimensional Critical Systems
By C. Itzykson ....................................... 11
Variational Principle for Quantum Effects on Nearly Sine-Gordon
Chains. By R. Giachetti and V. Tognetti (With 2 Figures) ....... 15
Quantum Theory of Planar Kinks in a Finite Easy Plane
Ferromagnetic Chain. By J.F. Lemmens and W.J.M. de Jonge .... 20
RAF Model and Solid Oxygen: Infinite Degeneracy, Soft Lines, No
LRO in Classical Approximation and Order by Quantum Disorder
By E. Rastelli and A. Tassi (With 2 Figures) ................ 25
Phase Transitions in Ising Superlattices
By D. W. Hone (With 2 Figures) .......................... 29
A Fermionic Treatment of the Frustrated Ising Model
By J.A. Blackman and J. Poulter (With 3 Figures) . . . . . . . . . . . . . 34
Calculation of Static Magnetic Susceptibilities of a Jahn-Teller E-
Doublet
By P. de Vries, A. Lagendijk, and H. De Raedt (With 1 Figure) 38
Part II Random Field Problems, Spin Glasses and Chaotic
Behaviour .
Critical Properties of the Random Field Ising Model
By J. Villain, T. Nattermann, and M. Schwartz ............... 44
Random-Exchange and Random-Field xv-Chain for 8=1/2
By T. Schneider and A. Politi (With 2 Figures) ............... 49
VII
Spin-glass-like Behaviour in Spinels
By E. Agostinelli and D. Fiorani (With 4 Figures) 55
Harmonic Magnons in Spin Glasses: Cdo.35MnO.65 Te
By D.L. Huber, W.Y. Ching, and T.M. Giebultowicz
(With 2 Figures) ......... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
On a Symmetric (2S+1)-State System Coupled to Its Environment:
Tunneling Splitting and Quantum Coherence. By T. Tsuzuki ..... 65
Regular and Chaotic Dynamics of Classical Spin Systems
By N. Srivastava, C. Kaufman, G. Miiller, R. Weber, and H. Thomas
(With 3 Figures) ................................. . . . . . 70
The Kicked Quantum Spin: A Model System for Quantum Chaos
By H.J. Mikeska and H. Frahm (With 1 Figure) ............... 75
Chaotic Dynamics of Spin Wave Instabilities
By S.M. Rezende, F.M. de Aguiar, and A. Azevedo (With 3 Figures) 79
Part III Theory of Spin Excitations
Spin 1 vs Spin 1/2 Antiferromagnetic Chains: The Staggered
Magnetization
By D.C. Mattis and C.Y. Pan (With 3 Figures) ............... 88
Excitations and Critical Behavior in Generalized Heisenberg Spin
Chains
By J.C. Bonner, G. Milller, and J.B. Parkinson (With 3 Figures) 95
Exact Results for the Out of Plane Dynamical Correlation Function in
a Classical Easy Plane Ferromagnet at Low Temperatures
By G. Reiter (With 2 Figures) ............................ 101
A Comparison of the Bethe Ansatz and Green FUnction Approaches
to Two-Magnon States of the Ferromagnetic Chain
By P.D. Lolyand W.K. Scott (With 1 Figure) ................ 105
Nonlinear Effects in Low-Dimensional Magnetism: Solitons
and Vortices. By A.R. Bishop, C. Kawabata, F.G. Mertens,
and G.M. Wysin (With 1 Figure) ......................... 109
Theory of Excitations in Incommensurably Modulated Magnets
By P.-A. Lindgard (With 2 Figures) ....................... 114
Linear Spin Dynamics of Incommensurably Modulated Magnets:
Numerical and Analytic Results
By S. W. Lovesey and A.P. Megann (With 3 Figures) ........... 120
On the Interpretation of Electronic and Phonon Anomalies in Mixed
Valence Compounds. By A. Stasch ........................ 125
VIII
Bloch Lines as Magnetic Excitations in Domain Wall Dynamics with a
Large Sensitivity to Initial Conditions
By J.J. Zebrowski and A. Sukiennicki (With 3 Figures) ......... 130
Dynamics of Magnetic Domain Walls and Barkhausen Noise in
Metallic Ferromagnetic Systems. By G. Berlotti . . . . . . . . . . . . . .. 135
Part IV Spin Excitations: Experiments and Computer Simulations
Magnetic Fluctuations and Excitations in the 8=1 Antiferromagnetic
Chains of NENP. By L.P. Regnault, W.A.C. Erkelens, J. Rossat
Mignod, J.P. Renard, M. Verdaguer, W.G. Stirling, and C. Vettier
(With 5 Figures) .................................. ~ . .. 142
Study of Longitudinal Fluctuations in CsNiFs by Means of Inelastic
Polarized Neutron Scattering. By U. Balucani, B. Dorner, K. Kakurai,
R. Pynn, M. Steiner, V. Tognetti, and R. Vaia (With 4 Figures) ... 147
Dynamics of Critical Fluctuations in Isotropic Ferromagnets: Current
Problems. By F. Mezei (With 2 Figures) .................... 152
Magnetism of MnSi and FeSi. By G. Shirane (With 5 Figures) .... 157
Neutron Scattering from Heavy Fermion Systems. By C. Broholm,
J.K. Kjems, G. Aeppli, E. Bucher, and W.J.L. Buyers
(With 3 Figures) ...................................... 162
Linear and Nonlinear Excitations in the 8=1/2 Ferromagnetic Chain
System [C6Hn NHS]CuBrS (CHAB)
By K. Kopinga and W.J.M. de Jonge (With 3 Figures) .......... 166
Doublings of Soliton Modes and Soliton Magnetic Resonance (SMR)
By J.P. Boucher (With 10 Figures) ........................ 171
Relaxation Phenomena in Non-linear Systems; A Mossbauer
Effect Spectroscopy and Susceptibility Study. By M. EIMassalami,
H.H.A. Smit, H.J.M. de Groot, R.C. Thiel, and L.J. de Jongh
(With 8 Figures) ...................................... 178
A Raman Scattering Study of the Spin-Phonon Interaction in Rutile
Structure Antiferromagnets
By D.J. Lockwood and M.G. Cottam (With 3 Figures) .......... 186
Raman Scattering Studies of Optical Magnons and of High-Energy
Magnetic Excitons
By P. Moch, A.T. Abdalian, and B. Briat (With 3 Figures) ...... 191
Spin-Dynamics Studies of Excitations in xv-Chains
By D.P. Landau, R.W. Gerling, and M.S.S. Challa (With 3 Figures) 196
IX
NUmerical Transfer-Kernel Results for the Classical xy-Chain in a
Magnetic Field
By R. W. Gerling, T. Delica, and H. Leschke (With 2 Figures) 199
Monte Carlo Simulation of the Quantum Sine-Gordon Chain
By S. Wouters and H. De Raedt (With 2 Figures) .............. 204
Index of Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . .. 209
*L ecturers , names are printed in italics.
x
Part I
Statistical Mechanics
and Mathematical Physics
