Gan Xuecheng, Tang Zheng, Zhang Wenjun, Xu Cong, Sun Xiaofan, Gao Zhangran, Wu Yizhang, Cai Hong-Ling, Wu X S
Collaborative Innovation Center of Advanced Microstructures, Laboratory of Solid State Microstructures, School of Physics, Nanjing University Nanjing 210093 P. R. China
RSC Adv. 2019 Feb 13;9(10):5470-5474. doi: 10.1039/c8ra10031d. eCollection 2019 Feb 11.
Molecular ferroelectrics are a kind of functional materials that have large application prospects. Comparing with the traditional inorganic ferroelectrics, they have some advantages, such as easy design, environment-friendliness, nontoxicity, and flexibility. In this study, a new molecular ferroelectric pyridin-2-ylmethanaminium perchlorate was discovered, which undergoes a ferroelectric phase transition at around 264.8 K. The spontaneous polarization reaches 0.22 μC cm, and the coercive fields are as small as 1.1 kV cm at 202 K. The single-crystal X-ray diffraction analysis reveals that the space group transforms from a polar space group of 2 at 173 K to a centrosymmetric space group of 2/ at 293 K. By analyzing the crystal structure changes below and above the phase transition temperature, it can be concluded that the phase transition is induced by the disorder of perchlorate. Its ferroelectricity was confirmed by the measurements of differential scanning calorimetry, dielectric and hysteresis loop.
分子铁电体是一类具有广阔应用前景的功能材料。与传统无机铁电体相比，它们具有一些优点，如易于设计、环境友好、无毒和柔韧性好。在本研究中，发现了一种新型分子铁电体高氯酸吡啶 - 2 - 基甲铵，其在约264.8 K发生铁电相变。自发极化达到0.22 μC/cm²，在202 K时矫顽场小至1.1 kV/cm。单晶X射线衍射分析表明，空间群从173 K时的极性空间群2转变为293 K时的中心对称空间群2/。通过分析相变温度上下的晶体结构变化，可以得出该相变是由高氯酸盐的无序引起的。通过差示扫描量热法、介电和磁滞回线测量证实了其铁电性。
