The Phase Transition from the SmC* to the Smc Phase Induced By an External Magnetic Field
Some chiral compounds exhibit a helicoidal smectic-C* (SmC*) phase which is of considerable interest due to its remarkable properties and potential applications. In the SmC* phase rod-like molecules are tilted with respect to the layer normal, and the director precesses from one layer to another so that the helicoidal structure is formed with a period of about 103 layers thicknesses. The period of the helicoidal structure is strongly sensitive to the strength of the field, electric or magnetic, so that at some critical field the sample unwinds and the structure becomes similar to that in the SmC phase. The critical field values depend strongly on the temperature.
KeywordsExternal Magnetic Field Classical Model Critical Field Transition Line Free Energy Density
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