Ris0-R-1O99(EN) DK9900089 Annual Progress Report of the Condensed Matter Physics and Chemistry Department 1 January - 31 December 1998 Edited by K. Bechgaard, K.N. Clausen, R. Feidenhans'l and I. Johannsen Ris0 National Laboratory, Roskilde, Denmark April 1999 30-31 Ris0-R-1O99(EN) Annual Progress Report of the Condensed Matter Physics and Chemistry Department 1 January - 31 December 1998 Edited by K. Bechgaard, K.N. Clausen, R. Feidenhans'l and I. Johannsen Ris0 National Laboratory, Roskilde, Denmark April 1999 Abstract The Condensed Matter Physics and Chemistry Department is concerned with both fundamental and applied research into the physical and chemical properties of materials. The principal activities in the year 1998 are presented in this progress report. The research in physics is concentrated on neutron and x-ray scattering measurements and the problems studied include two- and three-dimensional structures, magnetic ordering and spin dynamics, superconductivity, phase transitions and nano-scale structures. The research in chemistry includes chemical synthesis and physico-chemical investigation of small molecules and polymers, with emphasis on polymers with new optical properties, block copolymers, surface-modified polymers, and supramolecular structures. Theoretical work related to these problems is undertaken, including Monte Carlo simulations, computer simulation of molecules and polymers and methods of data analysis. The readers are invited to contact the department or the authors of the individual contributions for more detailed information than can be given in this report. The postal address is: Condensed Matter Physics and Chemistry Department, Ris0 National Laboratory. P.O. Box 49, DK-4000 Roskilde, Denmark. E-mail addresses may be found on the last page of this report. This report contains unpublished results and should not be quoted without permission from the authors. Front page illustration: A neutron diffraction pattern from the magnetic flux line lattice in the superconductor The flux line lattice symmetry is seen to be square and several orders of reflections are observed. ISBN 87-550-2508-0; 87-550-2509-9 (Internet) ISSN 0106-2840 ISSN 1397-8985 Information Service Department-Ris0-1999 Table of contents 1. Introduction and acknowledgements 9 Research projects 2.1 Theory 12 1. Theory of New Magnetic Excitation in the Colossal MR Material La(i.X)CaxMn03. 2. Perturbing the Haldane State. 3. Simple Solution to Problems Concerning Oxygen Ordering in YBCO 4. Phase Diagram for the Extended ASYNNNI Model. 5. Molecular Properties Calculated from a Model of Interacting Atoms, 6. Computer Simulations of Effective Potentials between Particles in a Liquid 7. Spin Waves in the Near-Ising ID ferromagnet CoCl2,2D20 2.2 Magnetism 19 1. Nuclear and magnetic structure of NiO nano-particles 2. High Field Phase of CuGeO3 3. Possible Kosterlitz-Thoulses transition in M11PS3 4. Magnetic structure of (Tmi.xYbx)Ni2B2C with x= 5,10 and 15 % 5. X-ray Scattering Study of Copper Magnetism in Non-superconducting PrBa2Cu306.92 6. X-ray resonant scattering study of the quadrupolar order in UPd3 7. X-ray resonant scattering study of the spin-density wave in a superlattice 8. Magnon Dispersion of Copper Tetramine Sulfate in the Antiferromagnetic Phase 9. The magnetic phase diagram of Ho:Tm thin Film Alloys 10. Unusual HighField Phase in a ID frustrated magnet 11. Magnetic Microstructure of Nanocrystalline Ni from Small-angle Neutron Scattering 12. Genuine Cluster Contribution in SANS of FeZr-based Amorphous Alloys 13. Magnetic Structure Determination and Phase Transitions in (Mn i.xFex)Sn2 14. Neutron diffraction studies of REFe4Al8, (RE = Dy and Nd) 15. Neutron Diffraction Studies of pure CeSb Single Crystals 16. Neutron Diffraction Study of Single-Crystal PuxUi.xSb 2.3 Superconducting Materials and Phenomena 35 1. Microstructure evolution in BiSCCO/Ag tapes. 2. Equilibrium Phenomena and Kinetics in a BiSCCO/Ag tape. 3. Magnetic field penetration and critical currents in BiSCCO/Ag tapes Investigated by Magneto-optical Field Imaging. 4. X-Ray Scattering of Charge Stripes and Phonons in La(i.6-X)Ndo.4SrxCu04 5. Superstructure Reflections in Lai.68Euo.2Sro.i2Cu04: Indication for Stripe Ordering? 6. Reorientation transition of the flux line lattice in TmNi2B2C studied by Bitter Decoration 7. Magnetic order of the Nd Sublattice in NdBa2Cu306+x (x=0.1,0.95) 8. Pinning of Magnetic Flux Lines in YBa2Cu3O6+x Superconductors by Neutron Irradiation 9. Superstructure formation and structural phase diagram of YBa2Cu3O6+x 10. Magnetic excitations in PrBa2Cu3O6+x 11. Pressure study of the magnetic order in Ris0-R-1O99(EN) 12. SANS Studies of the Role of Non-Locality on the Flux Line Lattice Square- Hexagonal Symmetry Transition in Lu(Nii.xCox)2B2C 13. Intertwined Symmetry of the Magnetic Modulation and the Flux Line Lattice in the Superconducting State 2.4 Structures and Defects 48 1. Microstructural Change Before Crystallization of Amorphous Alloys 2. Order-Disorder In Alite - Substituted Ca3Si05 3. The Fe-O-H-Cl System. A Neutron Powder Diffraction Study 4. The Structure of the TOTA Carbocation from Vibrational Spectra and Ab Initio Calculations 5. Photophysical Properties of Conformationally Proximal Pyrene Pairs on DNO Polypeptide Derivatives 6. Bithiophene Radical Cation: An Experimental and Computational Study 7. The Radical Cation of 1,4-Diaza[2,2,2]bicyclooctane (DABCO) 8. The Structure of Triphenylene Radical Cation: Resonance Raman Spectra and Molecular Orbital Calculations 9. The Radical Cation of N,N-Dimethylpiperazine: Dramatic Structural Effects of Orbital Interactions Through Bonds 10. The Molecular Structure of Dihydro-3,12-dibromo-7,8-dioxa[6]helicene is in the C/s-Conformation. 11. Does the Columnar Discotic Phase Exist for Triphenylenes? Structures of 2,3,6,7,10,11-Hexahydroxytriphenylene and 2,3,6,7,10,11-Hexaalkoxytriphe- nylenes. 12. Structures of CT-salts Based on Triphenylene and 2,3,6,7,10,11-Hexamethoxy- triphenylene 2.5 Structures and Interfaces 60 1. Determination of the Indium-induced Si(l 1 l)-(4xl) Reconstruction by Surface X- ray Diffraction. 2. Structural Changes Accompanying the Low temperature Phase Transition in the Ge(l 11)-(V3 x V3)R30-Sn o (3x3)-Sn System 3. Surface X-ray diffraction Study of the Ge(001)-(2 1 0 3)-Pb and (2 1 0 6)-Pb Reconstructions 4. Characterization of the Au3Cu(001), (110) and (111) Surfaces on an Atomic Scale by Surface x-ray Diffraction 5. Electrical and Optical Properties of Thin Indium Tin Oxide Films Produced by Pulsed Laser Deposition in Oxygen or Rare Gas Atmospheres. 6. Structural Investigation of the Cu(100)-c(2x2)-N Surface 7. Tensile and Compressive Interface Stress in Cu/Ni and Au/Ni Multilayers 8. Rotation of a Single Molecule in a Nanoscopic cavity 9. Ni particles on Silica studied by Anomalous Small Angle X-Ray Scattering 10. Initial stages of Cu growth on Ni(001) Surfaces 11. Aggregates in Hydroxides and Oxides of Aluminum Studied by SAXS 12. The Direct Bonding of Si wafers observed as Function of the Annealling Temperature by X-Ray Diffraction. 13. The Interface of Directly-Bonded Si Crystals, Measured by X-Ray Diffraction. 14. Froxen disorden in PS-PDMS Thin Films. Ris0-R-1O99(EN) 15. Temperature dependence of Lamellar Period and Flory-Huggins Parameter of PEP-PDMS measured by neutron Scattering 16. The Lamellar Period in Symmetric Diblock Copolymer Thin Films Studied by Neutron Reflectivity and AFM. 2.6 Langmuir Films 76 1. Positional Order in Langmuir Monolayers of Octadecanol 2. Hydrogen-Bond Induced Chiral Discrimination in Monolayers 3. Calcium Interaction with Insoluble Phospholipid Monolayers at the Air/Water Interface 4. Organisation of Membrane-Bound Polymer Brushes at the Air/Water Interface 5. Detailed Structure of Molecularly Thin Polyelectrolyte Multilayer Films on Solid Substrates as Revealed from Neutron Refiectometry 6. Formation of Interdigitated thin Films at the Air-liquid Interface by Molecular Design. 7. Crystalline Phases in Langmuir Films of Cholesterol 8. Cholesterol Derivatives at the Air-water Interface 9. Supramolecular Architecture Prepared in-situ at the Air-Aqueous Solution Interface; Thin Films of a 2x2 Silver Grid Complex 10. Self-Assembly at the Air-Water Interface. In-situ Preparation of Thin Films of Metal Ion Grid Architectures 11. Monolayers of Molecules Adopting an inverted U-Shape 12. Packing Stress Relaxation in Polymer-Lipid Monolayers at the Air-Water Interface Studied by X-ray Grazing Incidence Diffraction and Reflectivity 2.7 Microemulsions, Surfactants and Biological Systems 88 1. Behavior of a Charged Vesicle System under the Influence of a Shear Gradient: A Microstructural Study. 2. In Situ Studies of DVB-polymerization and Gelation 3. Water-Induced Reverse Micellization of Amphiphilic Block Copolymers: A Small-angle Neutron Scattering Investigation 4. Nematic-to-liquid transition of giant wormlike micelles studied by time-resolved small angle neutron scattering. 5. Limited Flexibility of Inter-protofilament Bonds in Microtubules Assembled From Pure Tubulin. 6. Modeling Elastic Properties of Microtubule Tips and Walls. 7. Mining Multi-channel EEG for Its Information Content: an ANN-based Method for a Brain-Computer interface. 8. Classification of Single EEG Trials During Preparation of Movement. 9. Three-dimensional Structure of 70S Ribosome: Joint use of Small-angle Scattering and X-ray Diffraction 10. SAXS Studies of the Interaction Between Beta-lactoglobulin and Dioleoylphosphatidylcholine (DOPC) in Aqueous Liquid Crystalline Phases. 11. Computor Simulations of the Copolymer Micelle Formfator 12. A Small-Angle Neutron Scattering (SANS) Study of Tablet-shaped and Ribbon- like Micelles Formed from Mixtures of an Anionic and a Cationic Surfactant 13. A Small-Angle Neutron Scattering (SANS) Study of Vesicles and Lamellar Sheets Formed from Mixtures of an Anionic and a Cationic Surfactant Ris0-R-1O99(EN) 14. Evaluation of the Geometrical Structure of Pure SDS and DTAB Micelles Formed at Different Concentrations of Added Salt Using Small-Angle Neutron Scattering (SANS) 2.8 Polymers 103 1.