By replacing germanium (Ge) atoms with silicon (Si) on the 〈111〉 surface of GeSi, one can create localized (surface) states, that can be used to create resonators (isolated defects) and waveguides (line defects), which are important components of nanoscale phononic interconnects. Using empirical potentials and molecular dynamics simulations, the propagation losses in such devices are studied as a function of the excitation frequency, temperature and geometry design. Such systems may be used as an additional way of data manipulation similar to the well-known electronic and optical communications.

Cobalt–Chrome (Co–Cr) is a biometallic alloy widely used in vivo for total joint replacement (TJR). In this study, Co–Cr was successfully electrochemically polished in terms of nanosized surface roughness and topography via an environmentally friendly and biocompatible solution based on Vitamin B4 (VB4). Voltammetry and chronoamperometry tests were used to determine optimum polishing conditions for the Co–Cr alloy, with atomic force microscopy (AFM) and scanning electron microscopy (SEM) providing surface morphology comparisons to determine the condition of electrochemical polishing. Energy dispersive X-ray analysis (EDX) combined with SEM revealed significantly smoother surfaces for each alloy surface while indicating that the elemental alloy composition ratios remained relatively unchanged before and after polishing.

Physical effects caused by the presence of interfaces between the domains of coexisting ferroelectric and antiferroelectric phases in solid solutions with small difference in free energies of the ferroelectric and antiferroelectric states are discussed in this review. There exist a number of solid solutions in which the two-phase state of domains of the coexisting phases may occur under certain conditions. We present here results of investigations of some effects directly caused by the presence of the interfaces between the domains of the coexisting ferroelectric and antiferroelectric phases. The phenomenological model describing the inhomogeneous state of coexisting domains of the ferroelectric and antiferroelectric phases is presented. Experimental studies of such inhomogeneous state are discussed using two systems of the PbZr1–y Tiy O3-based solid solutions. Detailed discussion of the process of local decomposition of solid solutions in the vicinity of ferroelectric–antiferroelectric interphase boundaries and formation of the mesoscopic system of segregates in the vicinity of these interphase boundaries and corresponding experimental results are presented. Results on influence of the system of segregates on dielectric and piezoelectric properties, and also on a dielectric relaxation are presented and discussed. The effects caused by the application of a DC electric field are considered and corresponding experimental results are presented. The experimental results demonstrating the possibility of control of piezoelectric parameters by an external electric field in materials with the antiferroelectric to ferroelectric phase transition via the intermediate state of the coexisting domains of these phases are given.

Nanoscaled titania is a modern material targeting, among others, to optoelectronic and photovoltaic applications. Titanium-based thin films are grown by radio frequency magnetron sputtering on glass, polyimide and silicon substrates inside a high vacuum chamber (base pressure 10–7 mbar). X-ray diffraction measurements show that if only Argon is used as the sputtering gas, then pure titanium metal films are formed. However, by controllable adding and increasing of the quantity of air through a fine (leak) valve in the vacuum chamber during the sputtering process, we manage to grow Ti(N)O and TiO2 films by reactive sputtering. Some of these films are found to be in an amorphous state or in a mixture of amorphous and nanocrystalline state. Post-annealing of the films under air at high temperatures (between 450–750 °C) results in the formation of nanocrystalline titania films; the phases of anatase and rutile are detected. Ultraviolet-visible absorption spectroscopy is used to measure the optical band gap of titania semiconductor. Finally, well-grown titania films show strong photoluminescence at near infrared as a result of a phonon-replica effect. Our work contributes to the better understanding of growth and optics of nanocrystalline titania films for largescale technological applications.

Magnetic properties of surfaces and interfaces in magnetically ordered materials have been attractive subjects in the field of magnetism research since around 1970 when the dead layer model was proposed. The present author applied Mössbauer spectroscopy for the study of this issue and denied the existence of magnetically dead layers in electrodeposited metal surfaces. In this article, it is introduced that a unique information can be obtained from Mössbauer spectroscopic measurements for the study of interface magnetism. The giant magnetoresistance (GMR) effect was discovered in 1988 in nanostructured magnetic multilayers and as an impact from this effect, the cultivation of a new branch in magnetism, “spintronics,” has been initiated. Magnetoresistance (MR) phenomena have been extensively studied and the tunneling magnetoresistance (TMR) effect was found to exhibit much larger magnetoresistance (MR) ratios than GMR, at room temperature. The MR phenomena, GMR and TMR, are interested not only from fundamental aspects but also from the viewpoints of technical applications. A great progress of magnetic recording technologies has been achieved by adopting GMR (and lately TMR) heads, with utilizing the principles of GMR and TMR. Since the role of interface is crucial in the processes of spin-dependent electron transport, the interface magnetism studies have attracted renewed attention. In this review, the recent developments in experimental studies on interface magnetism in relation to spintronics are described and the following two matters are featured. One is the temperature dependence of magnetization in the topmost interface layers, which is an important parameter to obtain a large MR ratio at room temperature. The other is voltage effects on magnetic properties. In metallic materials, an externally applied electric field can induce a significant change of the electronic structure solely at the topmost interface layer contacting with an insulating material. In other words, voltage effects on the magnetic properties of metallic materials are the subjects essentially belonging to the category of interface magnetism. A recent topic of particular interest is the influence of electric field on magnetic anisotropy. If the change of anisotropy caused by an electric field is satisfactorily large, the magnetization switching can be driven by an electric field, which will be a favorable technique concerning the energy consumption. Finally a possible reason why the dead layer model had been proposed for electrodeposited metal films is speculated.

The initial use of pyridine-2-amidoxime (NH₂paoH) in lanthanide(III) [Ln^III] chemistry is described. The reactions of Ln(NO₃)₃ · xH₂O (x = 6 for Eu and Tb; x = 5 for Dy) and NH₂paoH led to the isolation of complexes [Ln₂(NO₃)₆(NH₂paoH)₂] (Ln = Eu, 1; Ln = Tb, 2; Ln = Dy, 3) in low yields. The structure of 3 was solved by single-crystal, X-ray crystallography. Elemental analyses and IR spectroscopy provide strong evidence that 1 and 2 are isostructural with 3. The structure of 3 consists of dinuclear molecules in which the two Dy^III ions are bridged by two bidentate bridging (η¹:η¹:μ) and two chelating-bridging (η¹:η²:μ) nitrato groups. The Dy^III centers are each chelated by a N(2-pyridyl), N′(oxime)-bidentate NH₂paoH ligand and a near-symmetrical bidentate nitrato group. The coordination geometry of each Dy^III can be best described as a muffin-type (MFF-9). The 2D lattice (crystal structure) of 3 is built through H-bonding and π–π interactions. IR spectra of the complexes are discussed in terms of the coordination modes of the ligands involved (NO^–₃, NH₂paoH). The Eu(III) complex 1 displays an intense red, metal-centered emission in the solid state which is achieved by an indirect process (antenna effect). The Tb^III ion in complex 2 emits in the same region with the ligand.

Approximately 15 Mt/year of solid by-products (fly ash, bottom ash) are being produced by the lignite combustion in West Macedonia and Peloponnesus in Greece. The utilization of lignite byproducts, which are atmospheric dust components, is demanded to be significantly increased in the future. Potential environmental applications of these or some of these, by-products would make them a resource rather than a waste. In order to use fly ash as a resource, we synthesized TiO₂-fly ash nanocomposites in two different mass ratios (70%–30% and 80%–20% respectively). The nanocomposites were prepared using fly ash from Megalopoli (Peloponnese) by depositing TiO₂ in the form of anatase on the fly ash components using titanium isopropoxide as a precursor under mild hydrothermal conditions at 180 °C. Mineral as well as amorphous phase composition, particle morphology and physical properties of the prepared nanocomposites were characterized by XRD, SEM, SEM-EDS and N₂-sorption/desorption isotherms. Their photocatalytic activities in mineralising azo dyes in water were measured. An acidic (orange G) and a basic (yellow 28) azo dye were used in order to compare the activities of the nanocomposites and determine the parameters affecting the decomposition of dyes. The characterization of the nanocomposites showed that anatase nanoparticles are well dispersed on fly ash surface. More importantly both nanocomposites proved to be more effective in the photocatalytic decomposition of acid orange 10 indicating that they are more promising for use in decomposing acid than base azo dyes in water.