A two phase microstructure, consisting of nanocrystallites surrounded by an amorphous matrix, was produced by a melt spinning processing route. Alloys of this type have extrinsic properties that are dependent on the relative amounts of the amorphous and nanocrystalline phases. One method for examination of the properties of the nanocrystalline and amorphous phases is by Mössbauer spectroscopy. ...

Evolution of the Ti/a-GelSi trilayer reactions has been investigated using transmission electron microscopy and Auger electron spectroscopy. Instead of amorphous phase formation, as usually observed in the Ti/Si bilayer reaction, the crystalline Ti,GeS is the first phase observed during the reaction. Preceding the equilibrium C5CTi(Si,Ge),, a substitutional solid solution type C49-Ti(Si,Ge), fo...

The infrared spectra of solid ammonia at different phases and the existence of a metastable phase have been in controversy for the last fifty years. In order to address this problem, we studied the infrared spectra of solid ammonia in an ultrahigh vacuum chamber at distinct temperatures. Having prepared amorphous ammonia at 10 K, we observed a transition from the amorphous phase to the cubic cr...

The body-centered cubic (bcc) phase tends to preferentially nucleate during solidification of highly undercooled liquid droplets of binary alloy systems, including Fe–Co, Fe–Ni and Fe–Cr–Ni. We investigate a similar tendency during the partial devitrification of Co-rich amorphous precursors of composition (Co1 xFex)88Zr7B4Cu1 by identifying the structure and composition of the nanocrystalline g...

The transitions in disordered substances are discussed briefly: liquid–liquid phase transitions, liquid–glass transition and the transformations of one amorphous form to another amorphous form of the same substances. A description of these transitions in terms of many–particle conditional distribution functions is proposed. The concept of a hidden long range order is proposed, which is connecte...

Thin silicon films of varying thickness were deposited on foreign substrates by electron-cyclotron resonance chemical vapor deposition from SiH4-H2 mixtures at 600 K. Optical thickness measurements, Rutherford backscattering, and transmission electron microscopy reveal that a thin amorphous interlayer of some 10 nm thickness has formed upon the substrate, before the growth of a microcrystalline...

Understanding the evolution of amorphous and crystalline phases during atomic layer deposition (ALD) is essential for creating high quality dielectrics, multifunctional films/coatings, and predictable surface functionalization. Through comprehensive atomistic electron microscopy study of ALD TiO2 nanostructures at designed growth cycles, we revealed the transformation process and sequence of at...

We report large scale simulations of the blue phases of cholesteric liquid crystals. Our results suggest a structure for blue phase III, the blue fog, which has been the subject of a long debate in liquid crystal physics. We propose that blue phase III is an amorphous network of disclination lines, which is thermodynamically and kinetically stabilized over crystalline blue phases at intermediat...

In this study, mechanical activation (balland cryomilling) was successfully applied to obtain coamorphous mixtures of two BCS class II drugs, simvastatin (SVS) and glipizide (GPZ). This pharmacologically relevant combination of two drugs could produce a promising candidate for formulations intended for combination therapy of metabolic disorders. The co-amorphous SVS-GPZ mixtures (molar ratios 2...

Ge2Sb2Te5 and related phase change materials are highly unusual in that they can be readily transformed between amorphous and crystalline states using very fast melt, quench, anneal cycles, although the resulting states are extremely long lived at ambient temperature. These states have remarkably different physical properties including very different optical constants in the visible in strong c...