Thermoelectric properties of Al-substituted Ge clathrate compounds Ba8AlxGe46−x were investigated experimentally and theoretically. Polycrystalline Ba8AlxGe46−x (x=12–18) was synthesized by using an arc melting and a spark plasma sintering technique. The obtained samples show the n-type behavior and the carrier concentration decreases with increasing amount of Al composition from x=12 to 16. The reasonably large power factors was obtained: 900–1000 μW/cm K2 around 900 K. Theoretically electronic structure of Ba8Al16Ge30 was calculated by means of a first-principles method and then thermoelectric properties were analyzed on the basis of the result of the calculated electronic structure. The calculated thermoelectric properties agree with the experimental results very well in the wide range of temperature between room temperature and 900 K.

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We study anisotropic behavior of cavity polaritons in an organic microcavity composed of a single crystalline anthracene film grown into the gap of the Fabry‐Perot cavity by a method through capillary action. The anisotropic response of the cavity polariton appeared on the spectra depending on the linear polarized directions; two kinds of the polarization correspond to the principal axes of anthracene crystal. Transmission spectra were measured with various thickness of the anthracene film. The peak‐shift of the lower polariton mode depending on the thickness was obviously observed, whereas that of the upper polariton mode was not clearly observed be cause of the complicated shape of the spectra. This behavior for the upper polariton mode was analyzed on the basis of the convolution between the spectra of the cavity mode and the absorption due to the vibronic transition in anthracene. Cavity‐polariton dispersion as a function of thickness was obtained from peak‐shift on the spectra. Each thickness was determined by spectral fitting through calculation using the transfer matrix theory. Large vacuum Rabi splitting energies of this system were obtained from the dispersion as 0.20 and 0.34 eV for two kinds of the polarizations. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Amorphous Y-Fe-O ferrite thin-films were deposited on GGG (111) substrates using reactive RF magnetron sputtering with a Y 2.84 Fe 5.16 O 12 ferrite sintered target. After that, the thin-films were post-annealed in air at temperatures higher than 650 degrees Celsius for 3 hours to be crystallized. In the XRD diagrams, large diffraction peaks from only YIG ferrite (444) or (888) plane were observed in the samples postannealed at over 1050 degrees Celsius. The half value width (∆θ 50 ) in the rocking curve for YIG ferrite (888) was as small as 0.13 degrees. These results proved that the YIG ferrite films have been grown in hetero-epitaxial manner on GGG (111) substrate with high orientation. The YIG ferrite thin-films had reasonable saturation magnetization of 1.7 kG, relatively low coercivity of less than 5 Oe and small ∆H of around 70 Oe. The YIG ferrite thin-films are useful for microwave magnetic devices.

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