Single crystal

About: Single crystal is a research topic. Over the lifetime, 59617 publications have been published within this topic receiving 870828 citations.

Pressure Derivatives of Elastic Constants of Single‐Crystal MgO at 23° and ‐195.8°C

Abstract: The variation of elastic constants of MgO with pressure was determined by using McSkimin's pulse superposition technique. Measurements were made up to 2 kbars pressure at room temperature and liquid nitrogen temperature. The room-pressure values of the adiabatic elastic constants, based on a density at 23°C of 3.5833 g/cm3, are (in kilobars) :

Crystal-face dependence of surface melting.

Abstract: Ion-shadowing and -blocking experiments on a cylindrical single crystal of Pb reveal a strongly orientation-dependent disordering (melting) of the surface with increasing temperature. The thickness of the disordered surface layer is found to diverge logarithmically as the bulk melting point is approached. The process of disordering is shown to be driven by an orientation-dependent difference in free energy between the surface in its ordered and liquid states.

Crystal structure and morphology of syndiotactic polypropylene single crystals

Abstract: In the past several years there have been an increased interest in the crystal structure and morphology of s-PP due to the new development of homogeneous metallocene catalysts which can produce s-PP having a high stereoregularity. In this research, the crystal structure and morphology of s-PP single crystals grown from the melt were investigated. A series of ten fractions of s-PP was studied with different molecular weights ranging from 10,300 to 234,000 (g/mol). These fractions all possess narrow molecular weight distributions (around 1.1-1.2) and high syndiotacticities ([r]{approximately}95%). The main techniques employed including transmission electron microscopy (TEM), atomic force microscopy (AFM), wide-angle X-ray diffraction (WAXD), and small-angle X-ray scattering (SAXS).

Rapid formation of intermetallic compounds interdiffusion in the CuSn and NiSn systems

Abstract: Fundamental investigations were carried out to examine a new interconnection technology which is based on the rapid formation of intermetallic compounds composed of a high melting component (e.g. Cu or Ni) and a low melting component (e.g. Sn) between two layers of the high melting component at temperature just above the melting point of Sn. This reaction is known as isothermal solidification. The growth of the intermetallic compounds of the CuSn and NiSn systems were studied in thin films at temperatures from 513 to 673 K. At the beginning of interdiffusion, the Sn-rich intermetallic compounds ν (Cu6Sn5) and Ni3Sn4 grow fastest with a non-parabolic time dependence. The Cu3Sn phase grows parabolically, however, not the Ni3Sn2 phase. The Ni3Sn phase does not nucleate below 623 K in specimens with clean Ni/Sn interfaces. For the first time, the influence of the small grain size of the Cu or Ni thin films were studied by performing similar experiments with Cu or Ni single crystals. In the CuSn system the interdiffusion coefficients for Cu3Sn obtained from the thin film experiments are twice those obtained from the single crystal experiments. In the NiSn system there are no differences between thin film and single crystal results.

Single-Crystal CdSe Nanosaws

Abstract: We report the first successful synthesis and characterization of single-crystal wurtzite CdSe nanoribbons through a simple thermal evaporation process. Asymmetric growth of the nanoribbons occurs, yielding a sawlike shape with sharp teeth on one side. This asymmetric growth is suggested to be induced by the polarization of the c-plane in the wurtzite crystal structure.