Thin free-standing films (FSFs) of an antiferroelectric liquid crystal (AFLC) were investigated by transmission ellipsometry. The phase difference between p-polarized and s-polarized light was measured as a function of the temperature and the incidence angle of the light beam. It was found that the structure of an FSF with two layers is anticlinic (SmC* A) throughout the temperature range investigated whereas the bulk sample shows several phases, from SmC* A to SmA phases. The four layer FSF showed only one phase transition (from SmC* A to SmA) in this temperature range. Even for such a thin film as one with five layers, a subphase or subphases between SmC* A and SmA were found.

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The refractive indices of free-standing films (FSFs) of an antiferroelectric liquid crystal MHPOBC and a conventional smectic liquid crystal 8CB were studied by means of transmission and reflection ellipsometry. When the FSF thickness of MHPOBC is thicker than 260 nm, the refractive indices of FSFs appear to be the same as those of bulk smectic layers. In the case of thin FSFs of 8CB with a small numbers of layers, birefringence could not be obtained clearly by means of reflection ellipsometry.

The short-wavelength effects on the fluctuation-induced diamagnetism (FD) in bulk isotropic three-dimensional (3D) superconductors are taken into account by introducing in the Gaussian-Ginzburg-Landau approach different cut-off conditions. These calculations, which extend to the 3D case our previous results on layered superconductors, are then used to briefly analyse the FD data measured for the low-temperature superconducting alloy Pb-8 at.% In. These analyses confirm the adequacy of a total-energy cut-off for explaining, for low-temperature 3D superconductors also, the thermal fluctuation effects in the high-reduced-temperature region. These results thus provide further support to the recent proposal that, due to the localization energy, the size of the effective fluctuations cannot be appreciably smaller than the superconducting coherence length amplitude extrapolated to T = 0 K.

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