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Symmetry of the Model of a Crystal with a Periodic Defect: Point Defects in MgO Crystal
Author(s) -
Evarestov R. A.,
Smirnov V. P.
Publication year - 1997
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/1521-3951(199705)201:1<75::aid-pssb75>3.0.co;2-3
Subject(s) - supercell , crystal (programming language) , crystallographic defect , crystallography , symmetry (geometry) , superstructure , materials science , molecule , molecular physics , chemistry , condensed matter physics , physics , thermodynamics , geometry , thunderstorm , mathematics , meteorology , computer science , programming language , organic chemistry
Barium stearate multilayer films have been prepared by use of the Langmuir‐Blodgett technique transferring sequentially deuterated and nondeuterated bilayers on a silicon support. Combined X‐ray and neutron scattering experiments show a rearrangement of the molecules when the films have been annealed at temperatures higher than 60 °C. Whereas the periodicity of the barium sheets is unchanged, the intensity of the superstructure peak decreases close to the melting point of the stearic acid component (about 70 °C) and vanishes completely above. This behaviour is explained by the vertical movements and rearrangements of stearic acid molecules without noticeable evaporation of molecules.