Polar (Pyroelectric, Piezoelectric and Ferroelectric) Properties of two low molar mass mesogenic compounds in the solid state

We report on the evidence of a polar crystallization of the two mesogenic solids 4-cyano-4′-butyloxy-biphenyl 1 and p-n-hexylobenzyliden-p′-fluoroaniline 2. Pyroelectric, piezoelectric and optical second harmonic generation (SHG) measuements in the solid state and discussd. The ferroelectric switching of mesogenic solid has been observed for the first time by the example of compound 1. Ferroelectric loops in co-ordinates pyroelectric coefficient vs applied voltage have bn obtaind. The spontaneous polarization was measured by pulse pyroelectric technique to be Ps = 46 nC/cm2 for compund 1 and Ps = 25 nC/cm2 for compound 2. The piezoelectric coefficient evaluated for compound 1 was d 31 = 1.6 pC/N. A rough estimation of the efficiency of the second harmonic generation for compound 1 gives the value three times more than for crystal quartz.