Two-dimensional ferroelectricity in monolayer PVDF Langmuir-Blodgett films studied by optical second-harmonic generationстатья
Статья опубликована в высокорейтинговом журнале
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Дата последнего поиска статьи во внешних источниках: 18 июля 2013 г.
Аннотация:The two-dimensional (2D) ferroelectricity in monolayer Langmuir Blodgett (LB) films of copolymer vinylidene fluoride with trifluoroethylene (PVDF/TrFE) is studied by optical second-harmonic generation (SHG). The SHG temperature dependences are studied in order to reveal the ferroelectric behaviour of the films. For the monolayer LB films of PVDF/TrFE, as well as for the multiplayer LB films, a wide hysteresis in the SHG intensity under heating and consequent cooling is observed. This hysteresis is attributed to the first-order ferroelectric-paraelectric phase transition in the extreme case of literally 2D ferroelectric films. It is demonstrated that the main contribution to the nonlinear response of the LB films of PVDF/TrFE originates from fluctuations of the nonlinear polarization in inhomogeneous film structure. (C) 2002 Elsevier Science B.V. All rights reserved.