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Three kinds of thermochromic materials (DC8, DC12, DC16) were synthesized by linking the rigid 1,4-bis[2-(4-pyridyl)ethenyl]-benzene (bpeb) with different lengths of alkyl chains. They exhibit remarkable fluorescent color changes under the irradiation of 365 nm light with elevating temperature, which is supposed to be caused by the transition between the crystal state and the amorphous state. Interestingly, the DC16 solid also has a photochromic character. It should be noticed that the phase transition temperatures of three materials measured by differential scanning calorimetry are higher than those of the fluorescence color changes during the heating process. Thus, the allochroic effect is attributed to the synergistic effect of both heating and photo-inducement (365 nm). Ethanol can turn the heated powder into the initial crystal again which indicates that their thermochromic behavior is reversible and makes the fluorescence recover.

A new approach is used to analyze the experimental data on the temperature dependence of low-temperature thermal conductivity κ(T) of some typical disordered complex crystals: clathrate hydrates (tetrahydrofuran, methane, xenon), Sr8Ga16Ge30 and p-type Ba8Ga16Ge30 clathrate compounds, YSZ ceramics, molecular structural glasses of 1-propanol, glycerol and D-ethanol exhibiting glass-like behavior of κ(T), and some representatives of regular complex crystals: tetrahydrofuran clathrate hydrate, n-type Ba8Ga16Ge30 clathrate compound, CsDy(MoO4)2 layered crystal, 1-propanol, and D-ethanol. A universal approach to normalizing low-temperature thermal conductivity is proposed, based on the theoretical model of hybridized Klinger–Kosevich excitations. The low-temperature universal behavior of the thermal conductivity of both crystalline and amorphous solids is shown to be a result of the same phenomenon: the hybridization of acoustic and low-lying optical branches.A new approach is used to analyze the experimental data on the temperature dependence of low-temperature thermal conductivity κ(T) of some typical disordered complex crystals: clathrate hydrates (tetrahydrofuran, methane, xenon), Sr8Ga16Ge30 and p-type Ba8Ga16Ge30 clathrate compounds, YSZ ceramics, molecular structural glasses of 1-propanol, glycerol and D-ethanol exhibiting glass-like behavior of κ(T), and some representatives of regular complex crystals: tetrahydrofuran clathrate hydrate, n-type Ba8Ga16Ge30 clathrate compound, CsDy(MoO4)2 layered crystal, 1-propanol, and D-ethanol. A universal approach to normalizing low-temperature thermal conductivity is proposed, based on the theoretical model of hybridized Klinger–Kosevich excitations. The low-temperature universal behavior of the thermal conductivity of both crystalline and amorphous solids is shown to be a result of the same phenomenon: the hybridization of acoustic and low-lying optical branches.

The microindentation of thin polystyrene plates, which is an amorphous linear thermoplastic polymer with a glass transition temperature Tg ≈ 373 K, was carried out in the 77–295 K temperature range. A decrease in the temperature from 295 K to 140 K generated a two-fold linear increase in microhardness, which is in good agreement with the temperature dependence of the forced elasticity limit of polystyrene measured by other authors during uniaxial compression deformation. At temperatures of T = 77–140 K the local deformation of polystyrene was reversible: during heating to room temperature the impressions on the sample surface disappeared completely. Partial deformation reversibility was observed upon indentation in the temperature range of 140–190 K, but at indentation temperatures T > 190 K the impressions remained. The microstrain reversibility of polystyrene in nitrogen at, and close to, 77 K is due to the effect of the adsorption-active medium on the formation of crazes (fibrillar-porous nanostructures), the glass transition temperature of which is tens of degrees below that of bulk polymer.The microindentation of thin polystyrene plates, which is an amorphous linear thermoplastic polymer with a glass transition temperature Tg ≈ 373 K, was carried out in the 77–295 K temperature range. A decrease in the temperature from 295 K to 140 K generated a two-fold linear increase in microhardness, which is in good agreement with the temperature dependence of the forced elasticity limit of polystyrene measured by other authors during uniaxial compression deformation. At temperatures of T = 77–140 K the local deformation of polystyrene was reversible: during heating to room temperature the impressions on the sample surface disappeared completely. Partial deformation reversibility was observed upon indentation in the temperature range of 140–190 K, but at indentation temperatures T > 190 K the impressions remained. The microstrain reversibility of polystyrene in nitrogen at, and close to, 77 K is due to the effect of the adsorption-active medium on the formation of crazes (fibrillar-porous nanostructure...

Hafnium oxide (HfO $_2$ ) thin films were deposited on quartz substrate by radio frequency magnetron sputtering with power from 160 W to 240 W. The optical and microstructural properties of samples before and after annealing were characterized by XRD, XPS, UV-VIS-NIR spectrophotometer and ellipsometer. The results show optical transmittances with low absorption in wavelength range above $\lambda$ =200 nm for all samples. The appropriate annealing can transfer the amorphous state of as-deposited films to the crystal film, contribute to the growth of nanocrystalline and compressive stress, optimize the stoichiometry of the film and systematically improve film density and the refractive index. In consideration of the stability of proper refractive index (> 2) and high optical transmittance in UV band, HfO $_2$ films deposited approximately at 220 W can be used in UV anti-reflection system.

Ca-based bulk metallic glasses (BMG) with their unique properties being very low density, good compressive strength and shear modulus comparable to modulus of human bones have found utility in biomedical field. Their poor oxidation and corrosion resistance can be improved substantially when they are synthesized in a glassy state. Although, according to the confusion principle, the bulk form of binary metallic system is seldom possible; recent experimental studies have aimed to achieve these goals and succeeded in preparing CaxAly binary BMG with (x, y) pair as (8, 3), (13,14) and (61, 39). We examine and verify the amorphous structure and glass forming temperature of binary Ca61Al39(at.%) metallic glass using molecular dynamics simulations combined with an evanescent form for interaction potential at the experimental density. Good agreement is observed with recent in-situ high energy X-ray experimental findings for pair-correlation function g(r) and static structure factor S(q). Evidenced from the structural analysis, the estimated liquid to glass transition temperature (Tg) is found between 520 to 555 K. Large principal peak heights in g(r) and S(q) is attributed to the strongness of the potential, whereas the large-r Friedel oscillations results in to the oscillatory behavior of g(r). Nevertheless, present result for co-ordination number (NC) 12.44 to 12.79 is in excellent agreement with the experimental value 11.9 ± 0.3 at Tg, and changes by about 7.6% when temperature is varied from 300 to 1200 K while keeping the density constant. Unlike the other composition pair (x, y) for Ca-based BMG, a large co-ordination number is suggestive, and proposes a closed packed structure in its probable solid phase. Since the closed packed structures are commonly observed with metallic materials, this proposition is partly supported by a successful application of the evanescent form for bare-ion local pseudopotential to analyze the structural aspect of binary Ca61Al39 metallic glass.

This paper reports the preparation and characterization of amorphous tin oxide thin films by sol-gel spin coating technique. The structural properties were analyzed by using XRD, FESEM and EDAX measurements. XRD analysis reveals that the as prepared tin oxide thin films were amorphous in nature. No crystalline peaks corresponding to the tetragonal rutile structure of tin oxide were present in it. FESEM analysis reveals that the particles were uniformly distributed in the tin oxide thin films. EDAX analysis shows that the as prepared tin oxide thin films contain tin and oxygen. Optical study was done by using UV-Vis Spectrophotometer and Photoluminescence spectroscopy. Transmittance spectra show that as prepared tin oxide thin film has highly transparent up to 85%. The optical band gap was calculated using Tauc plot and the value of optical band gap was obtained as 3.64eV. PL study shows an intense and broad blue asymmetric emission band centered at 389nm. Electrical study was done by using Keithley's four probe techniques. The resistivity was obtained as 1.21 × 10−3Ωm. The Figure of Merit value was calculated using Haacke formula and the obtained value was 2.2139x105Ω-1. Thus good quality amorphous tin oxide thin films were successfully prepared by sol-gel spin coating technique.

The synthesis of rare-earth (RE)-based silica glass is currently a key challenge for the development of integrated optics devices such as lasers and optical amplifiers. In this work, Tm3+-doped 80SiO2−10ZrO2−10Al2O3 thin films were prepared by sol-gel and dip-coating methods. The structural and optical properties of thin films with different number of coating layers: 15, 20, 25 and 30 layers were investigated. It can be observed from X-ray diffraction (XRD) results that the thin films showed an amorphous characteristic with some crystalline peaks for samples with 20 and 25 layers. From Fourier transform infrared (FTIR) spectroscopy analysis observed that the presence of hydroxyl (OH) absorption and its vibrational (phonon) energy at the band of 3100 cm−1 to 3470 cm−1 which can reduce luminescence characteristic, and significantly affect the optical device performance. The refractive index increases with increasing number of coating layers due to the increase in density, whereas the thickness of the samples become less as the coating layers become denser.

The present work explains the structural analysis of Se-rich (Ge20Se80)90Sb10 glassy system prepared using melt-quenching technique. Thin films of (Ge20Se80)90Sb10 are prepared on well-cleaned glass substrates using vacuum evaporation technique. All the structural characterizations for (Ge20Se80)90Sb10 system are performed at room temperature (298 K). XRD spectrum verifies the amorphous nature of as-prepared sample with the possibility of short-range ordering in the sample. The spherical granular morphology of the thin film has been studied using FE-SEM. The purity and the precise composition of the thin films are determined using EDS. The distribution of the constituent elements is investigated using elemental mapping. Raman studies help in understanding the basic structural units comprising the prepared sample.

We have grown ZrO2 thin films on silicon, sapphire and Pt-Si substrates using pulsed laser deposition by varying oxygen partial pressure in the range ∼1×10−1 to 1×10−5 mbar at a substrate temperature of ∼373K. The influence of oxygen partial pressure on crystal structure, chemical composition, surface morphology, optical and electrical properties of the as grown ZrO2 thin films were investigated. X-ray diffraction studies showed that ZrO2 films grown at ∼1×10−1 and 1×10−5 mbar of oxygen partial pressure were amorphous in nature while monoclinic phase was observed in the range of oxygen partial pressure from ∼1 × 10−2 to 1 × 10−4 mbar with the variation in crystallite size from ∼26 to 10 nm. Atomic force microscopy studies confirmed the nanocrystalline growth of ZrO2 thin films with RMS surface roughness in the range ∼ 2.9 nm to 0.3 nm. For ZrO2 thin films, with decrease in oxygen partial pressure from 1×10−1 to 1×10−5 mbar, we have found a decrease in band gap value from 5.95 to 5.57 eV and an increase in refractive indices value from 1.96 to 2.21 respectively. The leakage current and capacitance of ZrO2 thin films in Pt/ZrO2/Pt capacitive structures were found to increase with decrease in oxygen partial pressure. ZrO2 thin film grown at oxygen partial pressure of 1 × 10−2 mbar showed dielectric constant of ∼48 with low leakage current density of ∼1.3 × 10−3 A/cm2 suitable for storage applications.

Ta [RT]/ CoFeB (2-50nm) [Ts = 500°C] /Ta [RT] films were grown on Silicon dioxide substrates by UHV magnetron sputtering system. The magnetic, microstructural and electrical properties were investigated as a function of CoFeB thickness (tCoFeB) at suitable substrate temperature (Ts). Further, we identify that, the strength of perpendicular coercivity (Hc┴)of the stacks mainly depends on the tCoFeB. Higher Hc┴ value of ≈ 564 Oe is observed for the thicker CoFeB film. The enhancement in the Hc┴ on increasing the film thickness upto 50 nm is due to the crystallization of CoFeB film at Ts = 500 °C. The morphological studies show larger grain size for thicker CoFeB film. A high value of electrical resistivity (ρ) is obtained by employing the standard four probe method, which further proves the amorphous nature of the CoFeB films. This Ta/CoFeB/Ta at Ts = 500 °C structures having high Hc┴ , large spin polarization (P) and low damping constant (α) values could be a capable candidate in the fabrication of novel spintronic devices.

The effect of annealing temperature on the optical and structural properties of Er3+-doped 80SiO2−10ZrO2− 10Al2O3 films fabricated on fused SiO2 glass by sol-gel-dip-coating are investigated. In this paper, the optical and structural properties were characterized by thin film analyzer, X-ray diffraction (XRD) and Fourier transform infrared (FTIR). From thin film analyzer, it showed that the film thickness decreased with the increment of annealing temperature while the refractive index exhibited the opposite trend. OH peak at the range of 3400 cm−1 to 3700 cm−1 which is obtained from FTIR spectra disappear for sample that were annealed at 800°C and 850°C due to absent of OH and water molecules. The XRD pattern shows a broad peak for all samples indicating the amorphous nature of the fabricated film. However, there is one crystalline peak detected at 2θ = 28.4° for sample 850° which is correspond to ZrO2.

SF6 gas is one of the greenhouse gasses which contributed to the global warming effect. Separation of SF6 and N2 was investigated on the P84 and P84/ZCC carbon membrane. Carbon membranes were prepared via pyrolysis process at 700°C under N2 atmosphere. All of the carbon membranes were characterized by X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). XRD results show a typical peak of carbon membranes at 2θ∼24° and 41-42° which correspond to the amorphous and aromatic graphite structures, respectively. The scanning electron microscopy image observed that the addition of ZCC filler has been successfully incorporated without producing surface defect on the carbon membrane. The introduction of zeolite-carbon composite particles into the co-polyimide matrix enhanced the selectivity of N2/SF6 by 136.85%. The permeability of N2 has improved by 7.65%. Yet the permeability of SF6 has decreased by 54.55%, which indicated the addition of ZCC filler gives a molecular sieving effect. It concluded that the P84/ZCC carbon membrane shows better N2/SF6 separation performance than the pristine P84 carbon membrane.

An amorphous metal-amino acid contains metal based on Aluminium and Methionine as a ligand, was synthesized. The fabricated amorphous Al-Methionine (a-AM) is done in water solvent under moderate thermal conditions. The advantages of using bio ligands, one of which is amino acid, can be used to biologically compatible material. The synthesis was optimized changing chemical (metal and ligand molar ratio) and process (temperature, time) parameters. The a-AM characterization was carried out by XRD, FTIR spectroscopy, FESEM, also gas sorption measurement (BET). From the N2 adsorption/desorption isotherm, the a-AM is classified as a type IV and has a mesoporous structure. The produced a-AM has a SBET area 287 m2 g−1, pore size 0.996 cm-3 g−1 and mean pore diameter 13.85 nm. After demonstrated in the dye adsorption, this material has potency as an adsorbent.

Rapidly quenched alloys of composition Fe83Sn5B12 and Fe78Co5Sn5B12 were irradiated by electron beam with 4 MGy dose. The aim of the presented study is examination of the influence of irradiation on magnetic properties and microstructure in as-cast and nanocrystallized ribbons. Amorphous samples after irradiation retained their soft magnetic properties and the hysteresis loops obtained a more upright shape with a higher value of saturation magnetic polarization. The Co-containing ribbon is superior in terms of magnetic softness and even after irradiation its saturation polarization is significantly higher with the value of 1.79 T.

Polymer composites have been reported as potential candidates for radiation shield due to their light in weight, low cost, flexible, and efficient. In this study, the synthesis of polyurethane has been successfully carried out by mixing polyol and isocyanate with three different compositions, such as 1:1, 1:2 and 2:1. The best composition among these ratios was chosen for further study by addition of Pb3O4 filler with the variations of 50, 66.6, 75 and 80 wt%. Then, the result was characterized using FT-IR to find absorbance of polyurethane at 1730 cm−1. After that, it was characterized using both XRD and SEM to show that polyurethane is an amorphous compound with an even distribution of Pb3O4 compounds. The X-ray absorption test was conducted to see the percent absorption capacity of each sample of which showed 96.8, 99.0, 99.7 and 99.7% in compared with Pb plate with 99.9% absorption. It showed that the polyurethane composites have potential as an X-ray shielding.

A novel rare earth doped lead borate glass system (65B2O3–xGd2O3–xSm2O3-(35-2x) PbO) has been prepared by the means of melt-quench technique. XRD results confirm amorphous nature of glass samples. The density of glasses has been measured using Archimedes’ method. The fundamental radiation shielding parameters such as mass attenuation coefficient and effective atomic number decreases as PbO is replaced by Sm2O3 and Gd2O3 in the glass series. Whereas, the thickness normalizing parameters such as mean free path (mfp) and half value layer (HVL) exhibit an increase in value with decrease in lead oxide content. As these glasses incorporate some rarer earth oxides, the glasses can also be potential candidate for radiation sensing applications.

Unlike crystalline materials characterized by long range ordering, amorphous materials show short and middle range ordering. The atomic arrangements in multi-component metallic/metal-metalloid glasses remain a challenging problem, especially their structure near crystallization point have not been reported. In a popular model for amorphous materials, the structure is characterized by two parameters: the fractal dimension (which represents the density of atoms in self-similar clusters) and cut-off length (which represents the length scale up to which the atom-atom correlations are significant). From analysis of synchrotron X-Ray diffraction data for as cast as well as vacuum annealed metal-metalloid glasses with composition Fe58Co25Nb7Cu1B9, we find that the fractal dimension increases from 2.24 for the as cast sample to 2.45 for partially crystallized sample annealed at 450°C. The cut-off lengths remain the same within error. Further, we find that the power law scaling proposed for as cast metallic glasses by Ma et al as q1.Va-1/df = 9.3 may be adequate for describing structure of metal-metalloid amorphous systems near crystallization.

Nanothin films of bismuth telluride Bi2Te3 were obtained by thermal sputtering in vacuum on a mica substrate with amorphous carbon and a copper sublayer. A sample with a specially created sharp thickness gradient was studied by transmission electron microscopy (TEM). An island-labyrinth structure of the film was revealed, with the size of islands in the range of about 7-25 nm. The film is amorphous at the beginning of the thickness gradient; in the studied regions of greater thickness, it crystallizes in the rhombohedral Bi2Te3 phase. High-resolution TEM has revealed crystallization of initially amorphous islands under the action of a focused electron beam of increased intensity in an electron microscope column.

Cu2ZnSnS4 (CZTS) thin films were developed for safe and inexpensive thin films. The research aims to provide detailed information about the morphology of CZTS grown by immersion and sulfurization techniques on soda-lime glass (SLG) and indium tin oxide (ITO). CZTS thin films were prepared in two stages, i.e., CZTS precursors were prepared by substrate immersion in precursor solution firstly and then sulfurization in a furnace with sulfur pellet addition and heat treatment (540 °C for 30 minutes). The CZTS thin films were characterized by XRD, SEM-EDX, and completed by Smartphone and CCD cameras for larger area observation. The EDX test produces Cu-poor and Zn-rich films. The structure of kesterite crystals and amorphous CZTS thin films on SLG and ITO substrates was identified through XRD characterization results. The sequential thickness of films from SLG A’s film, SLG B’s film, SLG C’s film, ITO A’s film, ITO B’s film, ITO C’s film is 11.64 µm, 9.33 µm, 17 µm, 11.96 µm, 3.64 µm, 62.08 µm. CZTS thin-film morphologies observed by using Smartphone camera, CCD, and SEM were showed that there were cracks and voids yielding inhomogeneous grains and high porosity thin films. The comparison revealed that the thin films grown on ITO showed smaller cracks and higher homogeneity than that on SLG.

The incorporation of ZnO in TiO2 is essential for improving physical and optical properties. In this study, thin films with molar ratios of 1:1 and 1:0.5 TiO2: ZnO were produced on glass substrates using the sol-gel dip coating method. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to characterize the microstructure and surface morphology of the films. Prism Coupler (Metricon Model 2010/M) was used to measure the refractive index and thickness of thin films. Image J software was used to calculate the surface porosity of thin films. When the ZnO concentration in TiO2: ZnO thin films was reduced to 0.5, higher porosity and a lower refractive index value were obtained. The results show that the ratio of ZnO had a significant effect on the refractive index values of TiO2: ZnO thin films. All films had an amorphous structure with no cracks. It was determined that the resulting films integrated with a prism coupler can be used as a transducer in an optical waveguide biosensor.

The Borate glass with composition 57.5B2O3 - 20Na2O - 20CaO – 1.5V2O5 – 1Er2O3 was prepared by conventional melt quenching method. The amorphous nature of the glass was confirmed by the XRD method. UV-Vis absorption spectroscopy in the wavelength range 400 – 1600 nm was carried out. The UV – VIS – NIR absorption spectra reveal 8 bands which were located at 450, 490, 519, 540, 660, 780, 980, and 1550 nm. and corresponding to 4F5/2, 4F7/2, 2H11/2, 4S3/2, 4F9/2, 4I9/2, 4I11/2, and 4I13/2, respectively. In addition, from the UV-VIS-NIR absorption spectra it was revealed the values optical band gap, refractive index and Urbach energy are 2.66 eV, 0.26 eV, and 2.4952, respectively.

The synthesized silicon carbide nano particles (2.5 gpl, range 40 to 70 nm) are dispersed randomly into electroless Ni-P matrix for Ni-P-SiC nanocomposite platings on an AISI1040 grade steel substrate (MS). The plating duration is set for one and half hour and thickness of deposits is found in the range of 12 to 18 micrometer. The scanning electron microscope attached in combination of energy dispersive spectroscopy furthermore X-ray diffraction techniques were exploited to analyze surface morphology, elemental composition and phase structure of the platings respectively. The results of these studies reveal successful fusion of SiC nanoparticles as white globules into the electroless Ni-P matrix and with those as-deposited platings have amorphous structure and heated platings (200°C and 400°C) changes from amorphous to crystalline structure. Further Ni-P/Ni-P-SiC platings are investigated for wear, corrosion and microhardness resistance by respective techniques. The results of these studies corroborate that inclusion of SiC nano particles into electroless Ni-P plating upto a great extent influence the microhardness, wear resistance moreover corrosion resistance in standard sodium chloride (3.5 %) solution. The phase transformation initiation of amorphous nickel is headed toward nickel phosphide and crystalline nickel completely at 400°C which uphold further improved wear, microhardness and corrosion resistance of nanocomposite Ni-P-SiC electroless platings.

Precursors of nanocrystalline Fe78Co5Sn5B12 and Fe78Co5Sn3P2B12 alloys were irradiated by high energy electron beam with doses of 4 MGy. Effect of electron irradiation on the magnetic microstructure of nanocrystalline alloys prepared from irradiated precursors by their annealing (380°C, 30 minutes, vacuum) was studied by Mossbauer spectroscopy. Analyzing the measured Mossbauer spectra we have followed the parameters like the direction of the net magnetic moment, intensity of the internal magnetic field and the volumetric fraction of the constituent amorphous and nanocrystalline phases. The direction of the net magnetic moment was the most sensitive parameter reflecting radiation damage and showed the tendency to turn to the ribbon plane after irradiation. Magnetic measurements performed on the studied alloys before and after irradiation also diclosed some changes of the microscopic magnetic parameters due to electron irradiation manifested on the shape of hysteresis loops. The results indicated that addition of phosphorus into the basic Fe78Co5Sn5B12 structure result in higher radiation resistance.

In the scheme of plasma-assisted RF-sputtering of the cathode from boron powder, a mode is revealed and a film of boron with thickness up to 500 nm in amorphous state is formed on the surface of AISI 310S high-chromium steel. It is shown that deposition of boron film leads to formation of multiphase multilayer hierarchically subordinate nanocrystalline structure in surface layer of steel with thickness up to 700 nm. Hardness of modified layer exceeds hardness of initial steel by 1.2 times, and Young's modulus—by 1.4 times. It has been suggested that the increase in the hardness of the steel surface layer is due, firstly, to the action of the Orovan mechanism (strengthening with nano-sized particles of borides), secondly, to the Hall–Petch mechanism (strengthening with grain boundaries and sub-grains), thirdly, to the substructural strengthening caused by the formation of the dislocation structure, and fourthly, solid-solution hardening associated with the doping of the γ-iron crystal lattice with boron atoms.

Phosphoric acid/hydrogen peroxide (H3PO4/H2O2) oxidizer mixture is used to grow films on high purity germanium (HPGe) crystals in Hydrofluoric acid with an objective to passivate the inter-contact region of HPGe detectors. The bonding characteristics have been investigated by IR transmission. The native oxide films consist of Ge-O bonding in cristalobite atomic configuration where both hexagonal and tetragonal germanium oxide signatures are present. Raman spectroscopy data indicate the amorphous nature of grown films. Scanning electron microscopy (SEM) clearly reveals formation of a porous layer that is Ge–Hx terminated as indicated by FTIR spectroscopy when high peroxide concentrations are employed for growth. On the other hand smooth and dense films appear at low H2O2 concentration with no Ge-H bonding signature. The chemically grown films are quite stable in HF unlike the unstable nature of native oxides of Ge. HPGe diode has been fabricated using lithium diffused and Pd surface barrier contacts. The inter-contact region is passivated using chemically grown oxide film. The film offers high resistive properties and inhibit surface leakage problem of the fabricated diodes.

Atomic structure is an important parameter to analyze material physical properties, but investigating the atomic structure is not simple task, especially for disordered structure like amorphous material. Radial Distribution Function (RDF) calculation from experimental X-Ray Diffraction (XRD) data is generally chosen to investigate the disordered structure since RDF can count the number of atoms on each radial distance from arbitrary reference atom. However, when the X-Ray source is below 8 keV (short maximum wave vector q ∼ 8 A−1), XRD data which uses Fourier Transformation (FT) will have low resolution. Therefore, we propose RDF calculation with Wavelet Transformation (WT) from our original wavelet function that was theoretically constructed using simple quantum model of interatomic bonding and semi-empirical method. Amorphous (Ge0.25Se0.75) and Agx(Ge0.25Se0.75)100-x with x = {5, 10, 15, 20, 25} were used as the validity check to compare the two RDF results from our model and the experimental XRD data. The comparison of the first and second peaks in our model and the experimental data indicates the minor error of our model approximately on 2.44% to 10.16%. This error range confirms the promising capability of our model to predict the atomic structure of disordered material like amorphous.

Hydroxyapatite (HA) is the most stable Calcium Phosphate salt (also known as Bone-mineral) which is present as inorganic part of human hard tissues having applications in orthopedics, dentistry, archeology, chromatography, environmental remedies as waste water treatment, pollutant gas adsorbent and so on. In this study an attempt is made to synthesize pure Hydroxyapatite and 5 wt% Strontium doped Hydroxyapatite (Sr doped HA) NPs using sono-chemical assisted hydrothermal technique. Strontium (Sr) is an essential trace mineral present in bone and it improves biological properties of HA so Sr is selected as dopant. Synthesized samples were characterized by X-Ray Diffraction (XRD), Fourier Transform Infrared (FT-IR) spectroscopy and Energy Dispersive X-Ray (EDX) Analysis. XRD analysis shows that XRD data of both samples match well with standard data (JCPDS Card No.- 09-0432) and have hexagonal crystal symmetry. Sr substitution in HA lattice increase cell parameters and shift diffraction peaks slightly to the lower value of diffraction angles. FT-IR analysis shows that all the characteristic transmission bands of Phosphate and hydroxide groups along with peaks of adsorbed water are present in FT-IR spectra of pure and Sr doped HA. However, transmission peaks of Nitrate are also present due to the fact that Nitrate compound was utilized in the reaction as calcium source. EDX analysis shows the presence of Sr ion in HA lattice. Ca/P ratio was 1.98 and 1.88 for pure HA and Sr doped HA respectively. High Ca/P ratio might be found due to presence of small amount of amorphous intermediate Calcium Phosphate phases or due to formation of Tetra-calcium Phosphate.

Bioactive glass (BG) has a broad variety of biomedical applications because of its distinctive ability to bond with bone by exchanging ions in simulated body fluid when implanted inside the body, it has drawn enormous interest. Osteoporosis is a main cause of loss of bone density and that adding strontium (Sr) to the matrix of bioglass stimulates bone formation and also increases bone density and mass. This study concerns sol-gel derived Sr doped bioactive glass (BG) (50.77SiO2−24.12Na2O–(23.39-x)CaO–xSrO–1.72P2O5) in the quaternary (SiO2−Na2O-CaO-P2O5) system (x=0, 3, 5 and 8 mol%).The effect of Sr on bone nodule-like formation was conducted by using Calcified Nodule Staining Kit (Cosmo Bio Co., Ltd) after 28 days culture with MC3T3-E1 osteoblast-like cells (Riken Cell Bank, Tokyo, Japan). In XRD, the amorphous peak is slightly shifted to lower 2θ° value after SrO was incorporated into BG. Mineralization staining revealed that the larger area of mineralized nodules was detected on Sr (3) BG than others. These results suggest that BG with SrO 3% is a good candidate for bone tissue engineering with fast bone formation.

Composite films of polycarbonate (PC), loaded with different amounts of bismuth oxychloride (BiOCl) as filler have been prepared by solution casting technique, with dichloromethane (DCM) as solvent. The filler was dispersed uniformly in the PC matrix, by using ultrasonic dispersion technique, at room temperature. Pure PC film and composite films with filler level (FL) equal to 0.5%, 5%, 10% and 20% (weight percentages) were cast from solution, using a leveled glass substrate, at room temperature. The composite samples (films) were peeled off from the glass substrate after 24 hours. The XRD scan (intensity versus 2θ) of PC shows a broad amorphous profile, as expected from a non-crystalline polymeric film, whereas the XRD spectra of the composite films showed several prominent x-ray diffraction peaks superposed on a broad profile, indicating semi-crystalline nature of the composites, due to BiOCl (filler). The optical (UV-Visible) absorption spectra of PC showed peaks at 307 nm and 349 nm, corresponding to incident (absorbed) photon energies of 4.04 eV and 3.55 eV, respectively, attributed to strong absorption at these energies by chromophores in the chemical structure of PC. The TG curves of BiOCl/PC shows multiple stages of degradation, especially at higher FL. The degradation starts beyond 300°C even for the 20 wt% BiOCl/PC film, indicating that these composite films have good thermal stability. DSC reveals a glass transition temperature whose value varies from 140°C up to 146°C with change in FL of the composite, indicating a upper working temperature of 125°C − 130°C.

In-depth measurements are reported for the imaginary parts of AC conductivity to understand the conduction mechanism of amorphous Se80-xTe20Pbx (x = 0, 1 and 2) chalcogenide glassy alloys in the frequency range 10 Hz to 500 kHz and over the temperature range 300 K to 320 K. The investigated chalcogenide alloys were prepared using melt-quenching technique and sub-micron structural features are also reported. The absence of any sharp characteristics peaks in x-ray diffraction spectra signify the amorphous nature of each examined glassy compositions, which is further validated by field emission scanning electron microscopy (FESEM). The deduced results are analyzed in the light of various theoretical models. A detail analysis reveals that the correlated barrier hopping (CBH) model is most appropriate to describe the conduction mechanism in these investigated amorphous alloys.

In this work, rapidly quenched amorphous cobalt-based ribbons with a metalloid content of 20% and the finemet type ribbons were investigated in as-quenched state. Their structure, magnetic properties magnetoimpedance (MI) behaviour were discussed in the context of the effective magnetic anisotropy peculiarities depending on the length of the ribbons. The experimental results and the results of the finite element model (FEM) calculations for MI were comparatively analyzed. A quantitatively higher magnetoimpedance effect was observed for FEM modeling case, due to the absence of contributions from surface anisotropy, anisotropy distribution and magnetostriction. The results of modeling and experimental studies were in qualitative agreement. Expected change in the type of the field dependence of the MI ratio from one-peak to two-peak was observed. The effective value of the anisotropy field was estimated by fitting the results of the experiment and modeling.

Mg-based alloys became a material of interest for biomedical applications. The major difficulty in the Mg-based alloy application is its rapid corrosion rate. Various coating methods are used to form a barrier layer onto Mg-based materials. In this work, a thin film of calcium phosphate was deposited on an Mg–0.8 at % Ca alloy using RF magnetron sputtering. As-deposited coatings were in an X-ray amorphous state. Post-deposition heat treatment resulted in the coating crystallization, exhibiting the pure HA phase. Heat-treatment at 450°C for 3 hours did not significantly change the coating integrity and adhesion strength to the Mg–0.8 at % Ca substrate. The Ca/P ratio, however, was changed from 1.85 for as-deposited to 2.00 for heat-treated samples. Both coating and substrate material after heat treatment exhibit preferential crystallographic growth in (002) direction with Tc(002) = 2.86 and 5.79, correspondingly.

Understanding the nature of the mid-gap defects in amorphous chalcogenide alloy-based phase change materials is crucial to guide the development of multi-level memories, selectors, and neuromorphic devices. Currently, however, the knowledge of the mid-gap defects is fragmented and the known structural and electrical characteristics of the defects cannot be unified in a single atomic model. In this work, a Ge–Ge chain defect model is built by artificial bond rearrangement in an amorphous GeTe network generated by atomic distortion, revealing a possible valence alternation mechanism in its formation. Atoms in the Ge–Ge chain are found to have a crystalline-like environment. The chain is found to have a negative-U property and to introduce mid-gap states. This model unifies the main known properties of the mid-gap defects in amorphous chalcogenide alloy-based phase change materials.

The present paper reports the decrease and increase of optical band gap from the pristine value upon annealing at below and above glass transition temperature of the sample. The thin films of As40Se50Ge10 with 800nm thickness were annealed at 140°C and 180°C. The structural characterization was done by X-ray diffraction and Raman spectroscopy. The optical transmission data was recorded by UV-Visible spectrometer in the wavelength range of 400-1100 nm. The indirect optical bandgap was found to decrease and again increased with change in annealing temperature. The films remain in amorphous state irrespective of the optical change and Raman shift. The surface morphology and composition of the film was checked in FESEM study.

Electron paramagnetic resonance studies of the xBi2O3−(30-x)Li2O-10AS2O3−58B2O3 (where x=5, 10, 15, 20 and 25 mol%) containing 2 mol% V2O5 as the paramagnetic probe were carried out at room temperature. These glasses were prepared using conventional melt quenching. The amorphous nature of the prepared glass samples was confirmed by x-ray diffraction studies. From the EPR spectra, the spin-Hamiltonian parameters (SHP) of VO2+ ions, dipolar hyperfine parameter (P) and Fermi contact interaction parameter (K), molecular orbital coefficients (α2 and γ2), the number of spins participating in the resonance (N), and susceptibility (χ) have been evaluated. From the spin-Hamiltonian parameters, it was concluded that the vanadyl ions exist as VO2+ ions in octahedral coordination with tetragonal compression with C4V symmetry and the ground state is dxy. Tetragonality (Δg||/Δg1) of V4+ ion sites exhibited nonlinear variation in the glass composition in all the glasses studied. Further, the theoretical optical basicity of the glasses has also been evaluated and it is observed that the changes in optical basicity values are in accordance with the changes in SHPs.

Silicon nanoantennas offer unprecedented versatility for light manipulation due to low absorption and high refractive index that enables strong magnetic and electric Mie resonances in the visible and near-infrared ranges. However, despite the flexibility of the underlying concept of all-dielectric nanophotonics, the functionality of silicon-based nanoantennas and metasurfaces is usually permanently fixed at the fabrication stage, being determined by the shape, size, and spatial arrangement of the structure. This hinders their application for cases when active and tunable operation is required. One of the ways to impose tunability onto all-dielectric structures is the introduction of inclusions made of phase change materials (PCM), which possess notably different optical properties in amorphous and crystalline states and can be switched reversibly and repeatedly between them. Here, we propose a design for a hybrid nanoantenna constructed from silicon with a thin layer of phase change material GeSbSeTe that allows dynamic control over the direction of surface plasmon polariton excited by the nanoantenna on a metallic film. In particular, we demonstrate the possibility of complete inversion of the directivity pattern of the excited surface plasmon polariton upon amorphous-to-crystalline switching of the PCM inclusion. The proposed design highlights the potential of hybrid Si/PCM nanoantennas as light modulators and elements for on-chip signal multiplexing and demultiplexing.

In the present experimental work electroless Ni-P/Ni-P-SiC nanocomposite coatings is developed and the effect of heat treatment on the hardness and wear behavior of Ni-P/Ni-P-SiC nano-dispersion platings is discussed. The as-plated plating of Ni-P-SiC shows amorphous character of these platings. On heat treatment upto 6000C in steps of 2000C, the platings show decrease in amorphous character and enhancement in crystallization due to formation of intermetallics of Ni-P and Si-P alloys. Above 400°C grain growth in SEM images is also observed. These changes have been suggested to cause increase in hardness, friction coefficient and wear resistance of these platings. However grain growth in case of 6000C heat treatment results in lowering hardness which has been attributed to higher grain boundary area, as compared to amorphous state, formation of galvanic cells between Ni matrix and intermetallics, reduction in the amount of phosphorous in the plating and disbonding between the mild steel substrate and the plating because of their differential thermal expansions.

Current work describes the production of multi-component single-layer and multi-layer coatings by pulsed magnetron sputtering. The study scrutinizes the coatings in terms of their composition (X-ray diffraction analysis, XRD) and microstructure (transmission electron microscopy, TEM). The results demonstrate that the multi-component single-layer Al-Si-N coatings have nanocrystalline structure, while all the layers of the multi-layer Al-Si-N/Al-Si-0 coatings are amorphous due to the ingress of oxygen.

To study the effect of Ag2O on the dielectric properties of the glass system with chemical composition xAg2O-(30-x)TeO2−20Li2O-50B2O3(x= 0,0.5,1.0,1.5 and 2.0mole%) was synthesized by melt quench technique. X-ray diffraction studies on the glass system revealed the amorphous nature. Frequency dependent AC conductivity measurements were implied on the prepared glass system in the high frequency range 5Hz-35MHz. AC conductivity measurements was recorded from room temperature to 350°C for all the samples. Presence of two ionic network modifiers such as Ag2O and Li2O plays significant role in the electrical transport properties like real dielectric permittivity(ɛ/) and loss tangent (tan δ). Addition of Ag2O causes breaking of base glass former B2O3 structural units with the creation of non-bridging oxygens (NBOs) in the glass network. Dielectric properties of the glass system show inconsistency in the results from room temperature to 100°C due to non-uniform charge carrier moments up to certain temperatures. Tangent loss and dielectric permittivity (ɛ/) decreased with increase of frequency and getting saturation at higher frequencies.

Structural properties of lithium niobium tellurite glasses of the composition (1-x)TeO2 – (x)LiNbO3 with x = 0.1, 0.2 and 0.3 have been investigated using total neutron diffraction and reverse Monte Carlo modelling. The glasses have been prepared using splat quenching method with starting material LiNbO3 and TeO2. Neutron diffraction have confirmed the amorphous nature of these glasses. Reverse Monte Carlo (RMC) modelling of the experimental data have been performed to calculate the 3-dimensional atomic configurations. The 3-D configurations have been analyzed to calculate partial atomic pair distribution functions, co-ordination number distribution, bond angle distribution as a function of tellurite concentration.

The authors report on the comparative study of formation of vanadium pentoxide (V2O5) nanorods deposited on amorphous glass substrate using thermal evaporation (TEVP) and pulse laser deposition (PLO) techniques. The x-ray diffraction pattern shows the formation of highly (001)-oriented, orthorhombic V2O5 thin films with high degree of crystallinity via both the fabrication techniques. Atomic force microscopy and field emission scanning electron microscopy revealed the formation of V2O5 nanorods at deposition temperature of 400°C. Further, the detailed growth mechanism ofV2O5nanorods formation is explained.

Polyaniline (PANI)/Camphorsulfonic acid (CSA)/ copper oxide (CuO) nanocomposite was synthesized by in-situ chemical oxidation method. PANI nanocomposites were characterized by Fourier Transform Infrared (FT-IR) Spectroscopy, X-ray diffraction (XRD). The XRD results shows broadening the peaks depict enhanced the amorphous with addition of CuO nanoparticles. The FT-IR results are reveals the chemical interaction and copper metal ions uniformly embedded in PANI matrix. The TGA results are shows enhanced thermal stability with increasing the CuO nano concentration. These results are suggesting PCC composite is a prominent candidate for supercapacitor properties and optoelectronics devices applications.

Reduced magnetic properties of Fe and FeCo nanoparticles due to their amorphous nature is major drawback when prepared by chemical reduction method using NaBH4. Hydrogenation is an effective alternate method to improve the magnetic properties of Fe and FeCo nanoparticles as it additionally reduces the adsorbed oxygen and oxide layers on the particle surface and improve the crystallinity. The Structural and morphological changes in Fe and FeCo nanoparticles before and after hydrogenation has been studied from their respective XRD and FESEM data. Enhancement in the overall magnetic properties of hydrogenated Fe and FeCo nanoparticles as compared to the as-prepared samples were analyzed from their room temperature M-H hysteresis loops traced using VSM.

The AZ91 magnesium (Mg) alloy is a high strength yet lightweight material, which is suitable properties for structural engineering application. However, the high surface reactivity of the alloy to a corrosive environment limits its extensive use. A barrier layer is necessary to reduce contact between the alloy and the environment. This paper reports the characteristics of a film formed on the AZ91 alloy by plasma electrolytic oxidation (PEO) in Na3PO4 solution at variation time of 30, 60, and 90 s. Surface characterization by SEM revealed that the formation of the PEO film was initiated at the β phase (30 s) and then expanded to the metal matrix (60 and 90 s). The film formed for 30 s was localized at β phase. At a prolonged time of 60 and 90 s, the film became more uniform with a thickness of approximately 2.5 and 5.0 µm, respectively. The film composed mainly amorphous Mg(OH)2 phase, as analyzed by XRD. The wear resistance, which was measured by abrasion test, showed that the film formed at the intermediate time of 60 s exhibited the highest abrasion rate of 3.22x10−4 mm3/Nm which was three times than that of the film formed at 30 and 90 s with abrasion rate of 1.35x10−4 and 1.47x10−4 mm3/Nm, respectively.

The synthesis of Fe3O4 – ZnO nanocomposite results is an interesting research currently which its application can be used in many ways such as gas sensor application. This research aimed to analyze the structure of magnetite (Fe3O4) - Zink Oxide (ZnO) nano composite through hydrothermal method. The procedures of Fe3O4 – ZnO nanocomposites synthesis started when Fe3O4 nanoparticles were decorated and added with ZnO. The proses of hydrothermal conducted at 180 °C for 12 hours then the synthesis results were cleaned by using water and etanol. The next step was calcined for 2 hours at 500°C and Fe3O4 – ZnO nanocomposites as the results. The sample of Fe3O4 – ZnO nanocomposites then characterized by X-ray diffractometer (XRD) and the pattern indicated the cubic structure index. The nanocomposites structure showed several peaks which were tapered up and the width narrowed. The results of XRD also described nanocomposite sample material has crystalline phase structure for 73.9% and of which 26.1% was amorphous.

WC-based powder used for sintering of hard alloys was studied after mechanical activation in a planetary ball mill with an acceleration of 60 g. Mechanical activation time ranged from 10 to 300 s. It is shown that the initial powder consists of a mixture of WC and W2C phases with lattice parameters that are in good agreement with data published. After 60 s of mechanical activation, an X-ray amorphous state is formed, and its relative content attains 15% after 300– second mechanical activation. It is shown that during mechanical activation the average powder particle size measured by SEM decreases due to destruction of agglomerates. The FWHM changes significantly after 10 s of mechanical activation, which can be due to an increased density of dislocations in all phases during mechanical activation.

In this work, undoped and Lithium (Li) doped Zinc oxide (ZnO) films were deposited on glass substrates using SILAR (Successive Ionic Layer adsorption and Reaction) method. Here 0.1M zinc sulphate mixed with ammonia solution is taken as the cationic precursor and distilled water at 70 °C as the anionic precursor. Lithium doping is done by adding anhydrous Lithium chloride (LiCl) in cationic solution at different atomic weight percentage (5%, 10% and 15%) as required.The samples were annealed for 1 hour at a holding temperature of 500 °C.The X ray diffraction analysis showed that the undoped samples are in amorphous phase. The doped (5 wt.%) samples showed peaks corresponding to ZnO hexagonal wurtzite structure and the calculations revealed that the lattice parameters are close to the standard values. But the Li doped samples at atomic weight percentages 10 and 15 showed much variation from ZnO crystal structure and 15 wt.% sample was completely turned to amorphous state. The UV-Visible transmission was 80% for the undoped sample. The transmission reduced to below 1.5% for the Li:ZnO film at 5 wt.% doping. Again the transmission properties improved with increase in doping and was 80% for the film with 15 wt.% doping.The photoluminescence spectra of the samples were drawn. The undoped sample showed a strong broader peak centered near 400 nm, corresponding to near band edge emission and some minor peaks at longer wavelength region, indicating the presence of defects. After doping at atomic weight 5%, this shorter wavelenghth emission had been reduced and the longer crystal defect related emission became dominant, which may be the cause for reduction in transmission of the sample. With increase in doping concentration it has been observed that the shorter wavelength emission became more dominant and is clearly shown by the 15wt.% sample.

Influence of Dy3+ ion on physical and absorption studies of zirconium based alkali borate glasses have been prepared using muffle furnace by conventional melt quench method. Samples were analyzed using certain measurements like XRD and UV-Vis. Physical parameters like density, molar volume were calculated. XRD spectra confirm the amorphous nature of all samples as there is no sharp peaks. Uv-Visible absorption studies were carried out and by utilizing Tauc’s equation direct and indirect band gap, Urbach energy was estimated. Energy band gap values are tabulated and discussed in detail for the better understanding.

One method to make a metallic alloy harder, stronger and lower in damping capacity is by manipulating the atomic structure of the alloy into amorphous. This study reports a successful fabrication of a bulk amorphous alloy with a composition of Zr60Cu25Ni5Al10 (at%). The alloy was fabricated by water quenching the induction melt of an arc-melted ingot. X-rays diffraction reveals that the specimen is fully amorphous and DSC measurements result in glass transition temperature, Tg, of 417 °C and onset crystallization temperature, Tx, of 485 °C. SEM image shows the amorphous surface of non-crystalline feature and Energy Dispersive Spectroscopy (EDS) analysis results in the nominal composition of Zr60Cu25Ni5Al10. The crystalline phases for the crystallized samples that were able to be identified are Zr2Cu and Zr2Ni.