Narrow Results

Magnetic susceptibility of the Co–Ni suck-cast plates underwent an abrupt change at 32 at% Ni due to phase transformation. Strain value of Co-32 at% Ni cast plate increased from 54 to 850 με as temperature decreased to 150 K. Phase formation of thin film is dependent upon deposition condition.

The crystallization process of Yttria Stabilized Zirconia (YSZ) thin film and the growth process of silicon oxide (SiO_x) have been directly investigated by in-situ heating TEM method from plan-view and cross-sectional directions. The YSZ layer is crystallized by the nucleation and growth mechanism. The nucleation is started from the surface region of the YSZ layer. Ultra thin SiO_x layer on the surface of Si substrate plays an important role in the strain relaxation in the crystallization process.

Nanocrystalline thin films of CdSe have been synthesized from an acidic solution containing CdSO₄ and SeO₂ by a cathodic electrodeposition technique under galvanostatic condition. The crystal structure and morphology have been investigated by Grazing angle X-Ray Diffraction (GXRD), Transmission Electron Microscopy (TEM) and optical microscopic measurement. The X-Ray and TEM diffraction patterns of the deposit reveal a bimodal size distribution with the presence of cubic (zinc blende) phase in the deposit. The particle sizes have been estimated from GXRD measurement found to be 4 nm to 6 nm, comparable to that obtained from TEM analysis. A Branched Fractal Pattern (BFP) in CdSe nanocrystals has been observed by optical microscopy, suggesting a diffusion-limited aggregation growth mechanism with fractal dimension 1.69 ± 0.04.

Hofstadter's fractal energy spectrum, which is also called Hofstadter butterfly, remained as one of the most interesting topics of condensed matter physics for decades. We study, in this paper, how different patterns of energy spectrum emerge when a graphene sheet is subjected to in-plane uniaxial and shear strain in the presence of transverse magnetic field. We discuss these patterns in the context of opening of the electronic energy band structure of graphene. We thus provide a unified framework for graphene under the coupled effect of strain and magnetic field. Due to such coupling, the energy bandgap opens when certain threshold of strain in the zigzag direction of graphene is crossed. The threshold strain value depends on the rationality of the parameter ϕ/ϕ_o, i.e., the ratio of magnetic flux through the deformed hexagonal plaquette and the quantum flux (h/e). Numerical results shows that the energy bandgap depends nonlinearly on the magnitude of strain, and that the threshold strain and energy gap decrease with decreasing magnetic field.

To apply the high hardness of TiN film to soft and hard multilayer composite sheets, we constructed a new type of composite structural material with ultra-high strength. The strain of crystal and cohesive energy between the atoms in the eight structures of N atom, Ti atom, 2N2Ti island and TiN rock salt deposited on the Al(001) surface were calculated with the first-principle ultra-soft pseudopotential approach of the plane wave based on the density functional theory. The calculations of the cohesive energy showed that N atoms could be deposited in the face-centered-cubic vacancy position of the Al(001) surface and results in a cubic structure AlN surface. The TiN film could be deposited on the interface of $\beta$-AlN. The calculations of the strains showed that the strain in the TiN film deposited on the Al(001) surface was less than that in the 2N2Ti island deposited on the Al(001) surface. The diffusion behavior of interface atom N was investigated by a nudged elastic band method. Diffusion energy calculation showed that the N atom hardly diffused to the substrate Al layer.