title: 4-(cyanomethyl)anilinium perchlorate: a new displacive-type molecular ferroelectric.
abstract: A new organic ferroelectric compound, 4-(cyanomethyl)anilinium perchlorate, proceeds a second-order phase transition from a paraelectric phase (P2(1)/m) to a ferroelectric phase (P2(1)) at 184 K. A perfect ferroelectric hysteresis loop was observed even at 10 KHz. It is the first example of a molecule-based organic ferroelectric whose polarization can be switched at such a high frequency. The temperature dependent second harmonic generation effect shows that the second-order nonlinear coefficient is nearly zero above T(c) and proportional to the spontaneous polarization below T(c), suggesting the occurrence of symmetry breaking, in good agreement with crystal structural determination. The origin of ferroelectricity was ascribed to the displacements of -NH(3)(+) cations and ClO(4)(-) anions from the symmetric positions including a small part of the order-disorder behaviors of the ClO(4)(-) anions.
authors: Ordered Matter Science Research Center, Southeast University, Nanjing 211189, People's Republic of China.
authors: Hong-Ling
authors: HL
authors: Cai
authors: Wen
authors: W
authors: Zhang
authors: Jia-Zhen
authors: JZ
authors: Ge
authors: Yi
authors: Y
authors: Zhang
authors: Kunio
authors: K
authors: Awaga
authors: Takayoshi
authors: T
authors: Nakamura
authors: Ren-Gen
authors: RG
authors: Xiong