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Droplets of molten alloys of composition Ge12Sb88, Ag0.055In0.065Sb0.59Te0.29, Ge4Sb1Te5, and Ge2Sb2Te5, used for optical data storage, surrounded by a molten dehydrated B2O3 flux is undercooled to 40-80 K below their liquidus temperature in a differential thermal analyzer. Results reveal that it is the presence of an incubation time that makes amorphization and therefore phase change recording possible in both optical and electronic media.

Expressions for interface stresses were developed using a simple model for the interfacial free energy of a semicoherent interface.

Nanoindentation is used to measure the hardness and a modulus in Ag/Ni multilayered thin films. Hardness and modulus are decreased at small bilayer repeat lengths. The results are explained by a combination of microstructural and stress effects on hardness. Interfacial effects on hardness and anomalous elastic properties are absent. The modulus data are compared to literature values of the elastic constants of Ag/Ni multilayers.

Interdiffusion in electrodeposited nickel-phosphorous thin films was investigated using an x-ray technique. The results showed that the structure and grain size of the films were determined by their composition. The fully amorphous multilayers at 120 degrees celsius featured a time-dependent diffusion coefficient. However, both fully crystalline and crystalline/amorphous multilayers exhibited a more limited diffusion behavior.

A study was conducted to analyze the magnetic structure of deformation-induced shear bands in amorphous metallic alloys. Magnetic force microscopy was utilized to carry out the observation and provide three-dimensional nanometer-scale topographic resolution and micrometer-scale magnetic resolution. Results indicated a structure consistent with tensile along the surface normal and/or in-plane compressive stress.

Uniaxial compression tests were performed on micron-sized columns of amorphous PdSi to investigate the effect of sample size on deformation behavior. Cylindrical columns with diameters between 8 μm and 140 nm were fabricated from sputtered amorphous Pd77Si23 films on Si substrates by focused ion beam machining and compression tests were performed with a nanoindenter outfitted with a flat diamond punch. The columns exhibited elastic behavior until they yielded by either shear band formation on a plane at 50° to the loading axis or by homogenous deformation. Shear band formation occurred only in columns with diameters larger than 400 nm. The change in deformation mechanism from shear band formation to homogeneous deformation with decreasing column size is attributed to a required critical strained volume for shear band formation. [ABSTRACT FROM AUTHOR]

The effect of changing the deposition rate on the development of stress in evaporated copper and silver thin films deposited on oxidized silicon was examined. In situ stress measurements were made during deposition in ultrahigh vacuum using a scanning laser curvature system. In some experiments, the deposition rate was alternated without interruption of deposition. For copper thin films, a change in deposition rate has no effect on the development of the tensile stress, while the magnitude of the postcoalescence compressive stress decreases with increasing deposition rate. In silver films, the film thickness at the tensile maximum increases slightly with increasing deposition rate, while the magnitude of the postcoalescence compressive stress again decreases with increasing deposition rate. Analysis of the heat flow during deposition shows that the radiative heating and condensation contribute roughly equally to the temperature rise of the sample. [ABSTRACT FROM AUTHOR]

The biaxial modulus and the linear coefficient of thermal expansion of sputtered amorphous Ge[sub 4]Sb[sub 1]Te[sub 5], Ge[sub 2]Sb[sub 2]Te[sub 5], and Ag[sub 0.055]In[sub 0.065]Sb[sub 0.59]Te[sub 0.29] thin films were determined from stress versus temperature measurements on two different substrates. Viscous flow was measured by stress relaxation at constant temperature using wafer curvature measurements. The shear viscosity increased linearly with time, which can be attributed to bimolecular structural relaxation kinetics. The isoconfigurational activation energy was 1.94±0.09 eV for Ge[sub 4]Sb[sub 1]Te[sub 5], 1.76±0.05 eV for Ge[sub 2]Sb[sub 2]Te[sub 5], and 1.33±0.09 eV for AgInSbTe. These values scale with the absolute melting temperatures of the material. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Sputtered amorphous Ag[sub 0.055] In[sub 0.065] Sb[sub 0.59] Te[sub 0.29], Ge[sub 4] Sb[sub 1] Te[sub 5], and Ge[sub 2] Sb[sub 2] Te[sub 5] thin films were studied by differential scanning calorimetry. The crystallization temperature and the heat of crystallization of the amorphous phases, the melting temperature and the heat of fusion of the crystalline phases, and the heat capacities of crystalline and liquid AgInSbTe were measured. The entropies of fusion are large (≥2R), which suggests a change of bonding type between liquid and crystal. In contrast to amorphous AgInSbTe and Ge[sub 4] Sb[sub 1] Te[sub 5], which upon heating crystallize to a single phase within a small temperature interval, the crystallization of amorphous Ge[sub 2] Sb[sub 2] Te[sub 5] is complicated by a subsequent cubic-to-hexagonal transformation. No thermal evidence of a glass transition was found below the crystallization temperature. The ratio of the glass transition temperature (approximated as the crystallization temperature) to the liquidus temperature is 0.490.56, which identifies the materials as marginal glass formers. The heat capacity measurements on AgInSbTe were used to estimate the temperature dependence of the difference in enthalpy, entropy, and Gibbs free energy between the undercooled liquid and the crystal. [ABSTRACT FROM AUTHOR]

Discusses calorimetric studies of crystallization and relaxation of amorphous silicon and germanium prepared by ion implantation. Determination of the amorphous-crystal interface velocity; Interface velocity for crystallization on substrates; Advantages of ion implantation in the study of thermodynamics and kinetics of crystallization.

Presents a study that investigated the effect of ion implantation and solute atoms on the interdiffusion in amorphous silicon/germanium multilayers. Diffusivities of other solutes such as platinum and bismuth; Investigation of the samples before and after ion implantation or thermal annealing; Effect of boron implantation.

Focuses on a study which presented a method for extracting the parameters describing the process of grain growth from calorimetric data. Factors considered for the presentation of the method; Use of the Kissinger method; Differences that are useful for distinguishing truly amorphous structures from microcrystalline ones.

Examines the dependence on temperature, dose and dose rate of the intermixing of silicon (Si) and germanium (Ge) atoms in the amorphous phase. Use of the Rutherford backscattering spectrometry technique; Relaxation in the diffusion coefficient; Target atom displacement in Si-Ge alloys of different average compositions.

Presents a study that measured crystallization rates in pure metals by monitoring changes in reflectivity on a picosecond time scale during pulsed laser quenching. Use of multilayered films to establish the relation of the transient decreases in reflectivity to melting; Results of depth profiling with Auger electron spectroscopy on laser-irradiated areas; Measurement of crystallization velocities.

Presents information on a study which measured the stresses in (111)-textured Ag/Ni multilayered thin films from the substrate curvature and from lattice parameter measurements using x-ray diffraction. Analysis of a thin film on a substrate under a biaxial stress; Measurement details; Results and discussion.