Exceptional second harmonic generation responses, switchable dielectric behaviours, and ferroelectric property in an adduct of hexamethylene-tetramine·bisnopinic acid
| Autor: | Chang-Feng Wang, He-Rui Wen, Chang-Shan Yang, Shao-Peng Chen, Yu-Hui Tan, Bin Wang, Yun-Zhi Tang |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Phase transition
Structural phase Condensed matter physics Chemistry General Physics and Astronomy Second-harmonic generation 02 engineering and technology Dielectric 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Ferroelectricity Signal Symmetry (physics) 0104 chemical sciences Adduct Physical and Theoretical Chemistry 0210 nano-technology |
| Zdroj: | Chemical Physics. 502:66-71 |
| ISSN: | 0301-0104 |
| DOI: | 10.1016/j.chemphys.2018.01.014 |
| Popis: | Most reversible phase transitions undergo transformations from high symmetry with non-active second harmonic generation (SHG) above Tc to low symmetry with active SHG below Tc (Tc refers the phase transition temperature). Here we display a new adduct of hexamethylenetetramine·bisnopinic acid, 1, which exhibits an abnormal phase transition from a low symmetrical structure with strong SHG responses above 235 K to a same symmetrical structure with weak SHG below Tc. X-ray single crystal diffraction research indicates the hydrogen-bond displacements trigger the structural phase transition. A pseudo symmetrical element C/2 exists in the low temperature structure (1-LTP) and vanishes in the room temperature (1-RTP). This abnormal change may be proved that its SHG responses from strong signal 1.04 (above Tc, about one-third of KDP) to weak signal 0.78 a.u. (below Tc). The ferroelectric measurement displays a typical electric hysteresis loop at room temperature with spontaneous polarization (Ps) 0.51 uC/cm2. |
| Databáze: | OpenAIRE |
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