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Phase transition in an organic ferroelectric: glycinium phosphite, with and without X‐ray radiation damage
Author(s) -
Bogdanov Nikita E.,
Zakharov Boris A.,
Chernyshov Dmitry,
Pattison Philip,
Boldyreva Elena V.
Publication year - 2021
Publication title -
acta crystallographica section b
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.604
H-Index - 33
ISSN - 2052-5206
DOI - 10.1107/s2052520621003127
Subject(s) - ferroelectricity , synchrotron radiation , synchrotron , diffractometer , materials science , phase transition , scattering , anisotropy , volume (thermodynamics) , crystallography , diffraction , dielectric , chemistry , analytical chemistry (journal) , optics , crystal structure , condensed matter physics , thermodynamics , optoelectronics , physics , organic chemistry
Thermal evolution of an organic ferroelectric, namely, glycinium phosphite, was probed by multi‐temperature single‐crystal diffraction using synchrotron radiation and also by a similar experiment with a laboratory X‐ray diffractometer. Both series of measurements showed a transition from the paraelectric to the ferroelectric state at nearly the same temperature, T c = 225 K. Temperature evolution of the unit‐cell parameters and volume are drastically different for the synchrotron and laboratory data. The latter case corresponds to previous reports and shows an expected contraction of the cell on cooling. The data collected with the synchrotron beam show an abnormal nonlinear increase in volume on cooling. Structure analysis shows that this volume increase is accompanied by a suppression of scattering at high angles and an apparent increase of the anisotropic displacement parameters for all atoms; we therefore link these effects to radiation damage accumulated during consecutive data collections. The effects of radiation on the formation of the polar structure of ferroelectric glycinium phosphite is discussed together with the advantages and drawbacks of synchrotron experimentation with fine temperature sampling.