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Room Temperature Lead-Free Multiaxial Inorganic–Organic Hybrid Ferroelectric
journal contribution
posted on 2019-09-26, 18:48 authored by Bin Wang, Dangwu Ma, Haixia Zhao, Lasheng Long, Lansun ZhengIn
recent years, molecular ferroelectrics have received more and
more attention. Nevertheless, the study of multiaxial molecular ferroelectrics
is relatively rare, which significantly restricts the development
of their applications in thin films and other potential fields. Here
we demonstrate the characteristics of a room-temperature lead-free
multiaxial inorganic–organic hybrid ferroelectric material
[(CH3)2NH2] [C6H5CH2NH3]2BiBr6 (1), which goes through a distinctly reversible phase transition
around 386 K and possesses six equivalent ferroelectric directions.
At 330 K, the remnant polarization (Pr) of 1 is ∼1.0 μC·cm–2, and the coercive field (Ec) of 1 is 20 kV·cm–1. The multiaxial and
switching polarization behaviors of 1 were declared with
piezoresponse force microscopy (PFM). Notably, the emergence of six
equivalent ferroelectric directions is induced by the easily disordered
cations and highly geometrically symmetrical anions, because they
usually lead to a large symmetry change in the order–disorder
types of ferroelectrics. This work provides an effective approach
to construct molecular multiaxial ferroelectrics.