Characterization of focal conics in chiral smectic C liquid crystals by X-ray microdiffraction

Focal conics consisting of an ellipse and a hyperbola in chiral smectic C liquid crystals aligned in surface-stabilized cells of medium thickness ( about 25 mm cell gap) were characterized in relation to the chevron structure by synchrotron X-ray microdiffraction. The focal conic texture is embedded in the chevron structure with a relatively sharp interface. The deformed layer of the focal conics is a kinked bookshelf consisting of a few slightly bent segments for small focal conics, whereas it is a bookshelf layer for large focal conics. Around the focus of the ellipse toward the hyperbola, a complicated layer structure appears, although the core region of small layer curvature has been hardly observed within the present experimental sensitivity. The broad and narrow walls of a zigzag defect in the same cell are analyzed for comparison.