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The structural analysis of a three-component Fibonacci (3CF) Ta/Al multilayer after extensive aging at room temperature was conducted. The objectives were to assess the long-term material properties of Ta/Al multilayers as well as the effect of degradation-induced disorder on the quasiperiodic diffraction spectrum. Results indicate that Ta/Al bilayers are unsuitable for multilayer applications due to the lack of thermal stability even at room temperature.

Raman scattering from longitudinal acoustic phonons in W/Ti Fibonacci superlatice was investigated. Doublet peaks due to the folded longitudinal acoustic phonons were seen in the Raman spectra as expected. Based on the Kronig-Penney model or the Rytov model, both the normal-mode frequencies and scattering intensities were numerically computed by a transfer-matrix technique. There was noticeable agreement between the results of quantitative computations and empirical data.

Transmission electron microscopy and x-ray and electron diffraction methods help measure the periodicity for W C and Mo Si metallic multilayers grown by magnetron sputtering. Satellite spacing in the low-angle regions of the diffraction patterns yield the modulation wavelength values for the multilayers. Comparison of the refraction corrections of the Bragg condition for the x-ray and electron diffraction patterns reveals that they are different.

Light scattering studies of longitudinal phonon modes in a ZnSe/ZnS(x)Se(1-x) lattice-mismatched superlattices reveal that the structure associated with the mismatch does not change for both acoustic and optical phonons. Calculated longitudinal elastic constants agree with the values predicted by an unstrained effective medium model. Raman spectroscopic studies help analyze the relationship between measured elastic constants and the lattice mismatch. A correlative study of fitting the spectra to a spatial correlation model helps derive the strain information. This calculation produces the observed longitudinal optical modes without incorporating the strain-related effects.

White-beam synchrotron X-ray topographic studies of twin structures in NdP5O14 single crystals reveals that the a-type twins along the a-axis are displaced. The displacement measurement indicates presence of monoclinic distortion associated with unit cell parameters. The twin structure of NdP5O14 is obtained from the fine-beam Laue diffraction pattern of the compound.

Transmission electron microscope facilitated the study of misfit dislocation geometry of the strained interface in InGaAs/GaAs single heterostructures. The interaction dislocation elasticity theory elucidated the gliding of misfit dislocation toward the substrate away from the strained surface. InGaAs/GaAs heterostructures exhibited a useful energy gap that ranged from 0.36 to 1.42 electron volts.

Shear elastic constant enhancement in quasiperiodic and periodic Ta/Al superlattices are due to the presence of atomic plane interfaces. The enhancement due to these interfaces, which extend over several atomic planes, is attributed to the mutual interdiffusion between Al and Ta.

Synchrotron radiation white beam X-ray topography facilitated the observation of growth bands and growth sector boundaries in Er-doped LaP5O14 (LPP) ferroelastic crystal and a type of abnormal boundary. Local displacements of La ions, as a result of local stress concentration along the (001) direction, caused abnormal boundary formation. The growth band and growth sector boundaries are LPP's primary defects.

The microstructure and transport properties of YBa2Cu3O(sub 7-delta)/La(sub 0.67)Ca(sub 0.33)MnO3 (YBCO/LCMO) bilayers are presented. The superconductivity and ferromagnetism coexisted in the bilayer with the YBCO thickness of 12.5 nm and they are related to the interaction between spin polarized electrons in the manganites and the copper pairs in the cuprates.

An examination of the Raman spectra of violet and infrared emitting Ge+ -implanted SiO2 films with special emphasis upon annealing temperature (AT) dependence of Raman scattering was conducted. Results show that the complete spectrum mainly consists of three bands at 220-280, 300 and 430 cm-1m, corresponding to scattering of Ge-related components, Ge nanocryistallites, and localized Si-Si optical phonons in the Ge neighborhoods, respectively.

The textures of Ta/Al multilayered thin films grown by magnetron sputtering were investigated using x-ray diffraction. The results showed that the thin film had Ta(110) and Al(111) axial textures with a mosaic spread of approximately +/- five degrees and coherency strains. Annealing treatment at 550 degrees celsius caused a significant amount of Ta and Al atoms at the interfaces to combine into TaAl3 with (202) and (002) textures.

Scattering from longitudinal guided modes (LGM) are observed in Brilloun scattering on ZnSe-ZnSe(1-x)S(x) strained-layer superlattices. The velocities of the LGM are obtained by the C11 elastic constant. The C11 and C44 elastic constants are calculated using the velocity of the first-order LGM of the quasilongitudinal acoustic mode and the quasitransverse acoustic mode of ZnSe-ZnSe(1-x)S(x) superlattice films.