Antiferroelectrics definition

By our definition, the tilt plane is normal to the polarization in the ferroelectric state in the illustration in Figure 8.13 this is a vertical plane normal to the plane of the page. Since there is no tilt of the director projected onto this plane, the phase should be considered a type of SmA. We name this structure SmAPp (an untilted polar smectic the subscript F referring to a ferroelectric structure, in this case a ferroelectric state of an antiferroelectric phase). The antiferroelectric phase is therefore also an SmA denoted SmAPA (the subscript A for antiferroelectric). While this idea is certainly intriguing, no such antiferroelectric has yet been discovered. 

The highly complex and unusual textures observed for B7 materials is complemented by unusual X-ray diffraction behavior. While the beautiful mystery of the B7 texture is not understood in detail, MHOBOW shows EO behavior, which allows some definitive statements regarding its nature. Thus, while some B7 materials are reported to be EO-inactive (no EO switching),54 and some are reported to exhibit antiferroelectric EO behavior,59 MHOBOW exhibits a unique texture change upon application of electric fields. 

C) using the same cell shows small anisotropy at zero field, as shown in Figure 9.30(d), because of the antiferroelectric molecular ordering. These results clearly show that the SmX phase exhibiting V-shaped switching definitely has a different molecular orientation from that in the antiferroelectric phase and the random orientation but has rather uniform orientation. 

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