8 research outputs found
Propagation of quasilongitudinal ultrasonic waves in the ferroelectric plane of TGS crystals
Above-room-temperature ferroelectricity and piezoelectric activity of dimethylglycinium-dimethylglycine chloride
Heavy-metal-free ferroelectrics are sought as environmentally compatible alternatives to commonly used inorganic oxides. Here, we demonstrate direct evidence of the ferroelectric properties of a hybrid organicâinorganic material, dimethylglycinium-dimethylglycine chloride. At room temperature, the compound crystallizes in the polar space group P21 and exhibits a switchable spontaneous polarization of 1.9Â ÎŒCÂ cmâ2. Ferroelectric properties are preserved in a wide temperature range up to about 401Â K, where the crystal undergoes the transition to the paraelectric phase of the space group P21/c. The temperature-dependent single-crystal X-ray diffraction study and the calorimetric data indicate an orderâdisorder contribution to the transition mechanism, which is consistent with the critical slowing down of the dielectric relaxation observed near the Curie point. The spontaneous polarization results from ionic displacements that are induced by changes in the disordering of the dimeric cations. In the ferroelectric phase, the crystal exhibits remarkable piezoelectric activity. The electromechanical and elastic properties of the material were thoroughly characterized