Coexistence of normal and inverse deuterium isotope effects in a phase-transition sequence of organic ferroelectrics.

ABSTRACT: Supramolecular cocrystals of anilic acids with 2,2'-bipyridines exhibit successive phase transitions as well as unusual isotope effects. Ferroelectricity driven by a cooperative proton transfer along the supramolecular chains is accompanied by huge permittivity (a maximum of 13 000) at the Curie point, as well as a large spontaneous polarization (maximum 5 μC cm^-2) and a low coercive field ranging from 0.5 to 10 kV cm^-1. Deuterium substitutions over the hydrogen bonds smoothly raise the Curie point and simultaneously reduce other phase-transition temperatures by a few tens of degrees. The coexistence of opposite isotope effects reduces the temperature interval of the intermediate paraelectric phase from 84 to 10 K for the 5,5'-dimethyl-2,2'-bipyridinium bromanilate sa

SUBMITTER: Horiuchi S 

PROVIDER: S-EPMC9076125 | biostudies-literature | 2019 Dec

REPOSITORIES: biostudies-literature