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X‐ray diffraction study of lithium hydrazinium sulfate and lithium ammonium sulfate crystals under a static electric field
Author(s) -
Sebastian M. T.,
Becker R. A.,
Klapper H.
Publication year - 1991
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s0021889891007112
Subject(s) - electric field , lithium sulfate , proton , polar , ferroelectricity , diffraction , lithium (medication) , chemistry , ammonium sulfate , sulfate , x ray crystallography , crystallography , materials science , optics , ion , ionic bonding , physics , dielectric , medicine , optoelectronics , organic chemistry , chromatography , quantum mechanics , astronomy , endocrinology
X‐ray diffraction studies are made on proton conducting polar lithium hydrazinium sulfate and ferroelectric lithium ammonium sulfate. The X‐ray rocking curves recorded with in situ electric field along the polar b axis of lithium hydrazinium sulfate (direction of proton conductivity) show a strong enhancement of the 0 k 0 diffraction intensity. The corresponding 0 k 0 X‐ray topographs reveal extinction contrast consisting of striations parallel to the polar axis. They disappear when the electric field is switched off. The effect is very strong in 0 k 0 but invisible in h 0 l reflections. It is present only if the electric field is parallel to the polar axis b . This unusual X‐ray topographic contrast is correlated with the proton conduction. It is supposed that, under electric field, an inhomogeneous charge distribution develops, distorting the crystal lattice. Similar experiments on lithium ammonium sulfate also show contrast variations, but of quite different behaviour than before. In this case they result from changes of the ferroelectric domain configuration under electric field.