High Angle Side Research Articles

The structural, magnetic and electrical properties of zinc-doped orthorhombic calcium ferrite nanoparticles: Memory device and high-frequency applications

Calcium ferrite nanoparticles (NPs), doped with Zinc in the range of 10–50[Formula: see text]mol%, were synthesized through a solution combustion method using citrus Limon extract as a reducing agent, followed by calcination at 500∘C. The synthesized samples are characterized with different techniques. Bragg reflections confirmed the formation of orthorhombic crystal structure. The shifting of the peak toward higher angle side is observed with increase in the dopant concentration. The surface exhibited irregular shapes and sized NPs with pores and voids in their morphology. The direct energy band gap increases from 2.91 to 2.97[Formula: see text]eV with increase in Zinc concentration. Further, magnetic and dielectric properties were carried out to know their importance in the high-frequency devices. Magnetic parameters, such as saturation magnetization (Ms), remanence (Mr), and coercivity (Hc) values, are discussed. Ms, Mr and Hc increase with increase in dopant concentration upto 30[Formula: see text]mol% and thereafter decreases. The dielectric studies revealed a decreasing dielectric constant from 2.98 to 1.84 as the dopant concentration increased. These findings suggest the potential use of these samples in memory devices and high-frequency applications.

Impact of Nd3+, Er3+ions on the structural, morphological and opto-electrical properties of ZrO2/La2O3doped Y2O3 ceramics

In the present work, the authors have studied double doping of Rare Earth Elements (Nd3+, Er3+) into the lattice of Y2O3 ceramic in the presence of sintering additives ZrO2+La2O3 having formula (Y0.915-xZr0.02La0.06Nd0.005Erx)2O3 where x= (0.5, 1.0, 1.5 at. %). The samples are synthesized using co-precipitation method. X-ray diffraction results reveals the formation of Y2O3 structure having cubic unit cell and matched with JCPDS card No. 41-1105. A gradual shift towards higher angle side at 2θ = 29.2° has been observed with variation in Er doping. The particle size varied from 123 nm to 52 nm with doping and has a homogenous distribution. The presence of different dopants have been confirmed by XPS. The powder mixture was sintered at 1700 °C for 10hrs in an inert atmosphere, though resulting in translucent pellets when measured in the range of 200–2200 nm, due to non-uniform heating and different grain size. Under the excitation of 350 nm, the samples emitted blue, green, violet and indigo colours wavelengths, confirming transition from 4F11/2 orbitals and their band gap also decreases from 5.2 eV to 4.80 eV. The sintered samples presented a dielectric constant of 15, which goes up to 18 upon increasing the concentration of Er. These results demonstrated the correlation and the effect of double doping on Y2O3 for its opto-electronic applications.

Synthesis, structural, morphological and optical properties of environment friendly yellow inorganic pigment Bi4Zr3O12

This study reports on the structural, morphological, microstructural, electronic and optical properties of 5 nm (annealed at 300 °C) and 8 nm (annealed at 500 °C) sized nanocrystals of yellow inorganic pigment Bi4Zr3O12 prepared by sol-gel auto-combustion technique. Increase in the annealing temperature from 300 °C to 500 °C does not led to structural phase change but results in minor shifts in the 2θ position of Bragg peaks towards the higher angle side, which is attributed to reduction in the unit cell volume due to well crystallization. Phase pure formation and well crystallization of 8 nm sized Bi4Zr3O12 pigment in the fluorite type fcc symmetry in the space group Fm3‾m (No. 225) have been revealed first time by detailed Rietveld profile refinement of the X-ray diffractogram, FTIR, SAED and HRTEM analysis. The FESEM micrographs showed micro-flower type morphology of the rod shaped nanocrystals of the Bi4Zr3O12 pigments. EDS and XPS analysis confirmed the stoichiometry of the constituent elements present in the Bi4Zr3O12 pigments. XPS analysis evaluated +3, +4 and −2 oxidation states of the Bi, Zr and oxygen ions respectively and also rule out presence of organic species in the two pigments. ESR, Fluorescence and XPS analysis affirmed formation of oxygen vacancies in the two pigments. UV–Vis–NIR optical reflectance data showed marginal increment in the optical band gap upon raising the annealing temperature but 8 nm sized Bi4Zr3O12 nanocrystals have shown greater reflectance in comparison to 5 nm sized Bi4Zr3O12 nanocrystals. The photoluminescence spectroscopic analysis and CIE coordinates along with CCT values showed that yellow Bi4Zr3O12 pigment could be useful for optical devices and yellow pigment applications.

Chemical stability and electrical properties of Ba1−xCaxCe0.8Gd0.2O3−δ (0 ≤ x ≤ 0.06) proton conductor

The effect of Ca content on chemical stability and electrical properties of Ba1−xCaxCe0.8Gd0.2O3−δ (BCCG, 0 ≤ x ≤ 0.06) proton conducting electrolyte is investigated in this work. The BCCG pellets were fabricated via a solid-state reaction method and high-temperature sintering at 1600 °C for 10 h in air. In XRD patterns, BCCG exhibited an orthorhombic phase, and the diffraction peaks of calcium-modified BaCe0.8Gd0.2O3−δ (BCG)-based samples shifted toward the high-angle side compared to BCG, indicating that Ca2+ occupies the A site. The chemical stability showed that adding a small amount of Ca2+ improves the stability against water while it deteriorates the stability in CO2-containing atmosphere. The highest conductivity was obtained for 1% Ca substitution (x = 0.01, BCCG1), where it increased from 1.1 × 10−3 to 2.8 × 10−3 S cm−1 at 400 °C and from 1.7 × 10−2 to 3.1 × 10−2 S cm−1 at 800 °C compared to that of x = 0. The partial conductivities were greater for BCCG1 compared with BCG material. Proton conductivity was dominant for BCCG1 sample at 600 °C.

Accurate and time-saving quantification of a component present in a very small amount in a mixture by the direct derivation method

In quantitative phase analysis (QPA) using the direct derivation (DD) method, total sums of diffracted/scattered intensities for individual components are used as observed quantities. Fluctuation in their relative intensity ratios induces errors in derived weight fractions, and it ought to be suppressed for improving the accuracy in QPA, in particular, of a component that is present in a small amount. The fluctuation is primarily caused by the termination in summing/integrating diffracted/scattered intensities on the high-angle side. It is usually associated with changing the 2θ range in whole-powder-pattern fitting (WPPF) used to decompose the mixture pattern into individual component patterns. In this study, calculated patterns for individual components, fitted in WPPF, are normalized so as to give the unit area when they are separately integrated over their definition ranges in 2θ. The termination effect could effectively be reduced by extending the definition range to a certain high-angle limit. Scale parameters for adjusting the calculated patterns become non-fluctuating against the change of the 2θ range in WPPF. Thus, the time spent for intensity data collection of mixture patterns can be reduced by shortening the scan range. The present procedure has been tested with binary mixtures containing small amounts of crystalline phases of 0.02–0.4 wt%. QPA could be conducted with errors of 0.01–0.03 wt% for both inorganic materials chosen as ideal samples and pharmaceutical materials as practical ones. QPA of an amorphous component present in a small amount is also discussed.

Effects of solution treatment and cold rolling on structure and tensile properties of hot-rolled Ti–7.5Mo alloy

The effects of solution treatment (ST) and cold rolling (CR) on structure and tensile properties of a heavily hot-rolled (HR) Ti–7.5Mo alloy were investigated. Experimental results indicated that, after HR with a one-pass 65% reduction in thickness, the pores in as-received samples substantially disappeared, the misorientation angle distribution became broader, and grain texture shifted toward $$\left\langle {10\bar{1}0} \right\rangle$$. Post-HR ST produced an orthorhombic α″-phase with fine needle-type morphology and caused misorientation to narrow down to 55°–65° with substantially random texture; post-ST CR caused misorientation shift toward high-angle side and texture toward $$\left\langle {10\bar{1}0} \right\rangle$$ and $$\left\langle {2\bar{1} \bar{1}0} \right\rangle$$. With an increase in reduction in thickness, α′(102) intensity increased at the expense of two adjacent (112)/(022) α′′-peaks. All X-ray diffraction, metallography and electron backscattered diffraction on scanning electron microscope results indicated that pre-ST HR did not affect the formation of the desired low-modulus α′′-phase when the alloy was subsequently solution-treated. From a practical point of view, the most optimal tensile properties may be found in the sample solution-treated at 900 °C for 30 min and cold-rolled by a 20% reduction in thickness, which demonstrated a yield strength of 924 MPa, an ultimate tensile strength of 933 MPa, a tensile modulus of 73 GPa, and an elongation of 26%.

Physicochemical characterization of different cellulose polymorphs/graphene oxide composites and their antibacterial activity

In order to investigate the interaction of graphene oxide (GO) with different cellulose polymorphs (I and II), we synthesized cellulose (I and II)/GO composites using the sonication method. Interestingly, no new peaks were observed in the FT-IR pattern of the cellulose (I and II)/GO composites, indicating that no chemical reactions took place between GO and cellulose. The X-ray diffraction patterns of cellulose I and II/GO composites were slightly different than those observed for cellulose I and II, indicating that some physical interactions occurred between the GO and cellulose. Unexpectedly the $d$-spacing values and the diffraction plane at the high-angle side were most likely expanded in cellulose I rather than in cellulose II by adding GO, confirming the highest reactivity of GO toward cellulose I rather than cellulose II. Furthermore, SEM images showed that the conformal coating of GO on cellulose I was larger than that on cellulose II due to the strong adhesion between the GO and cellulose I. Cellulose/GO showed antimicrobial properties, and GO was found to be promising for textile antimicrobial finishing.

Investigation of morphological and structural properties of V incorporated SnSe2 single crystals

The unique ternary compositions VxSn1-xSe2 (x = 0, 0.15, 0.25 and 0.5) have been grown in single crystal form by direct vapour transport technique. The as-grown crystals have been examined under Carl Zeiss optical microscope for morphological studies. The tiny flakes have also been observed by scanning electron microscope and it reveals the layered structure of as-grown ternary alloys. The powder XRD pattern infers hexagonal lattice structure with 2H poly type and P3¯m1 space group. The XRD pattern shows shifting of diffraction peaks on higher angle side as content of vanadium (V) increases, confirms substitution of V-atoms on tin (Sn)-atom sites. Using transmission electron microscope, the nano-structures have been found in sono-chemically exfoliated samples. The selected area electron diffraction pattern has been obtained using 200 kV electron beam and reveals the single crystalline nature of VxSn1-xSe2 (x = 0, 0.15, 0.25 and 0.5) ternary alloys. The Raman spectra show SnSe2 type A1g and Eg vibrational modes and on increasing V content blue shift in A1g peak indicates that the V-atoms well substitutes on Sn-site.

An unexpected reactivity during periodate oxidation of chitosan and the affinity of its 2, 3-di-aldehyde toward sulfa drugs

In an attempt to determine the reactivity during the periodate oxidation of the vicinal amino sugar, chitosan was oxidized by KIO4 in a neutral medium. The reactivity was unexpectedly found to be low. The formation of di-aldehyde chitosan (DACT) might cause the low reactivity of chitosan oxidation. Therefore, density functional theory (DFT) calculations were carried out, which revealed that the greater stability of the cyclic amino iodate intermediate might retard the ring opening to form DACT. Furthermore, the affinity of the formation of two novel Schiff bases from the interaction of delivered DACT with two sulfa drugs [sulfanilamide and sulfathiazole] was also investigated using aldehyde content estimation. DACT and Schiff's bases were characterized by FT-IR spectroscopy, X-ray diffraction, and DTA analysis. The X-ray diffraction plane (110) of DACT at the high angle side was expanded more by sulfathiazole than sulfanilamide, indicating that sulfathiazole reacted effectively with DACT. The lowest interaction of DACT with sulfa drugs could be ascribed to the lowest aldehyde content and the intramolecular hemiacetal formation that hinders the Schiff's base condensation.

Investigations on mechanical and electrical properties of N+ ions implanted TiN thin films

In the present work, we have grown titanium (Ti) thin films using DC sputtering system in argon atmosphere. Ti films are implanted using low energy ion beam(having 70 keV energy) at a fluence of 2 × 1016 ions cm−2 by varying the implantation angles from 15° to 45°. TiN films were then characterized for their structural, mechanical, optical and electrical properties. XRD measurements show an enhancement in the (1 1 1) peak with increase in implantation angle indicating the improvement in the crystallinity due to deeper implantation of N ions in host lattice. Also, a small shift in this peak towards higher angle side is noticed with the implantation angle which confirms that strain is modified depending upon the implantation angle. The change in the strain value in turn is responsible for the variation in various physical properties. UV–Vis measurements show decrease in optical band gap (from 2.41 eV to 2.39 eV) while improvement in electrical conductivity with implantation angle. Furthermore, increase in implantation angle leads to enhancement in mechanical hardness of the TiN thin films from pristine 3.0 GPa–19.6 GPa for 30° angle.

A comparative of structural, optical, mechanical and electrical properties of alkaline earth metal substituted tellurite glasses

In the present work, the glass systems 0.70TeO2–0.30MO and 0.65TeO2–0.35MO (M = Ba, Sr) were prepared and characterized by X-ray diffraction, Fourier transform infrared spectroscopy, UV–vis spectroscopy and differential scanning calorimetry. The structural studies show that amorphous alkaline tellurite glasses are made up of vibrational units of molecular water group, hydroxyl bonding, symmetrical stretching vibration of Te–Oax bonds in the deformed TeO4 and stretching and bending vibration of Te–O–Te linkages in TeO4/TeO3 + d polyhedra/TeO3. In the X-ray diffractograms, shifting of amorphous peak was observed towards higher angle side with the strontium substitution in comparison to barium substitution due to lower ionic radii. The optical band gap of investigated glasses was found to lie in the range 2.94–3.31 eV and was found to be lower in SrO added glasses than that of BaO added glasses. This may be due to the presence of more number of non-bridging oxygen in Sr substituted glasses than Ba substituted glasses. The Ba substituted samples were observed to be denser than Sr substituted glasses. Ultrasonic longitudinal and sheer velocities were found in the range of 3160–3210 and 1785–1850 m/s, respectively and were observed to be higher in Ba substituted glasses. The ac conductivity spectra were found to follow Jonscher power law and conduction mechanism is governed by overlapping large polaron tunneling model created with non-bridging oxygen and Tellurium ions.

Deep boron diffusion induced surface damage in silicon

This paper presents deep boron diffusion induced damages in silicon (100), (110) and (111) surfaces. The silicon (100) and (110) samples showed a broad hump at the higher angle (ω) side during x-ray Rocking curve measurement; whereas, the (111) sample shows an additional broad peak at higher angle side. All the diffused samples showed two distinct contours in reciprocal space mapping measurements. Due to the diffusion process, surface roughness of the silicon samples is found to be increased from 10nm to 110nm, 70nm and 30nm for the silicon (100), (110) and (111) samples respectively.

X-ray diffraction study of Al–Ge melts in a wide range of temperatures and concentrations

An X-ray diffraction study is performed of the structure of Al–Ge melts containing 0 at.%, 10 at.%, 20 at.%, 30.3 at.%, 40 at.%, 50 at.%, 60 at.%, 70 at.%, 80 at.%, and 100 at.% Ge near the liquidus line at 1273 K. The melts containing 40 at.%, 70 at.%, and 80 at.% Ge are studied in the temperature range up to 1823 K. The structural factor (SF) curves of the melts have a shoulder on the high-angle side of the first maximum at contents above 20 at.% Ge; the position of the shoulder coincides with that on the SF curve of liquid germanium. An increase in temperature leads to gradual smoothening of the shoulder because of the increase in the structural homogeneity of the melts, which is attributed to the metallization of the residual covalent bonds between germanium atoms. The structure of the melts is found to be microheterogeneous for germanium contents above 20 at.%, which is due to the coexistence of microclusters of liquid germanium and those of the melt with 20 at.% Ge, which provides a satisfactory description of the experimental SF curves in the concentration range 20-100 at.% Ge at temperatures near the liquidus line.

Microstructure, optical and structural characterization of Cd0.98Fe0.02S thin films co-doped with Zn by chemical bath deposition method

Fe-doped CdS (Cd0.98Fe0.02S) and Fe, Zn co-doped CdS (Cd0.98−xZnxFe0.02S (x=0.02, 0.04, and 0.06)) thin films have been successfully deposited on glass substrate by chemical bath deposition technique using aqueous ammonia solution at pH = 9.5. Phase purity of the samples having cubic structure with (111) as the preferential orientation was confirmed by X-ray diffraction technique. Shift of X-ray diffraction peak position towards higher angle side and decrease of lattice parameters, volume and crystallite size confirmed the proper incorporation of Zn into Cd–Fe–S except Zn=6%. The compositional analysis (EDX) showed that Cd, Fe, Zn and S are present in the films. The enhanced band gap and higher transmittance observed in Cd0.94Zn0.04Fe0.02S films are the effective way to use solar energy and enhance its photocatalytic activity under visible light. The enhanced green band emission than blue band by Zn-doping evidenced the existence of higher defect states.

Iron doped ZnO nanocrystals and their structural, optical and magnetic behavior

This present investigation deals with the synthesis of Fe doped ZnO nanocrystals by chemical method of microwave irradiation technique and the special attention is given to structural, optical and magnetic behavior. The X-ray diffraction analysis confirmed the single phase ZnO wurtzite structure without any impurity or secondary phase formation. The shifting of [101] peak in the higher angle side is due to the smaller cation of Fe3+ than Zn leads to the change in lattice parameters. The formation of metal oxide bond at 450cm−1 is confirmed by Fourier transform infrared spectrum and the Raman modes ∼324cm−1, 432cm−1 and 564cm−1 correspond to ZnO is identified by micro Raman spectrum. The band gap energy of the samples increases with the increase of Fe concentration due to the increase of crystal size. The ZFC–FC curve confirms the absence of Curie temperature below 350K. The room temperature magnetization measurement shows the paramagnetic behavior in all samples.

Spray pyrolysis deposition of Cu–Zn–In–S solid-solution thin films with tunable compositions and band gaps

Cu–Zn–In–S solid solution thin films with tunable compositions and band gaps were deposited on glass substrates using a chemical spray pyrolysis approach. XRD results reveal the cubic-structured Cu–Zn–In–S films without detectable impurities. The successive shift of XRD patterns toward high-angle side of ZnS with increasing ZnS molar fraction in products proves a formation of Cu–Zn–In–S solid solutions. SEM images and EDAX analyses demonstrate homogeneous surface morphologies and adjustable compositions of Cu–Zn–In–S films, which results in film band gaps broadly tunable from 1.54eV to 3.61eV. These sprayed Cu–Zn–In–S solid solution thin films may find potential uses in photovoltaics and photocatalysis.

Effect of Addendum Height and Teeth Number on Asymmetric Normal Contact Ratio Spur Gear Based on Load Sharing

This study explores the influence of some gear parameters such as addendum height, teeth number and module on load sharing aspect and the subsequent stress analysis. The multi pair contact model in finite element technique is used for a reasonable accurate prediction of the stresses with the application of load at high pressure angle side. Also, a unique Ansys parametric design language code is developed for this study. Finally the increase in addendum height results to increase the bending stress for a load at critical loading point. However the increase in teeth number and module leads to decrease in the load sharing based bending and contact stresses.

Influence of Pressure Angle on Load Sharing Based Stresses in Asymmetric Normal Contact Ratio Spur Gear Drives

The aim of this paper is to investigate the influence of pressure angle on drive and coast sides in conventional design asymmetric normal contact ratio spur gear, considering the load sharing between the gear teeth pair. The multi pair contact model in finite element analysis is used to find the load sharing ratio and respective stresses. It has been found out that the predictions through multipoint contact model are in good agreement with the available literature. A unique Ansys parametric design language code is developed for this study. It is found that, the maximum fillet stress decreases up to the threshold point for drive side (35o) and coast side (25o) pressure angles, beyond this point it increases. The load share based maximum fillet and contact stresses are lower in the high pressure angle side than that of the low pressure angle side, when it is loaded at the critical loading points.

Effective factor on antibacterial characteristics of Mg1−XNiXO solid solution

Mg1−XNiXO solid solution powder samples with different chemical compositions were prepared by heating MgO–NiO mixtures at 1300°C for 12h in air. From XRD measurement, all powder samples were indexed as a single phase of cubic structure, of which the diffraction peaks shifted to high-angle side with the increase of doping amount of NiO. The pH values of the solution dispersed with the powder samples decreased when the doping amount of NiO in solid solution was increased. Antibacterial activity of the powder samples was examined by colony count method. In the result, the antibacterial activity of Mg1−XNiXO was remarkably weaker than original MgO powders, irrespective of the kind of bacteria. In addition, it was found that the antibacterial activity of Mg1−XNiXO reduced with increasing the doping amount of NiO. Two factors, the generated amount of O2− and the eluted amount of Ni2+ ions affected the antibacterial activity of Mg1−XNiXO solid solution. Especially, the stability of O2− in aqueous solution is dependent on pH value. Therefore, the strength of antibacterial activity was associated with the pH values in the dispersed solution of Mg1−XNiXO.

Influence of niobium ion implantation on the microstructure and tribological properties of TiAlN coatings

To improve the performance of TiAlN coatings used for cutting tools, the metal vacuum vapor arc (MEVVA) ion implantation was used to enhance hardness and wear resistance of the coatings. In this paper, TiAlN coatings were deposited on the substrates of cemented carbide (WC-TiC-Co) with magnetic filtered arc ion plating(MFAIP) method and implanted with niobium ions at 40kV with the doses of 1×1017 and 5×1017 ions/cm2 by MEVVA ion source. HRTEM, EDS, and GIXRD tests are used to investigate the effects exerted by ion implantation doses on the microstructure, microhardness and tribological properties of the TiAlN coatings.EDS results showed that the projected range of Nb-implanted TiAlN coatings was about 130nm and corresponded well with the results calculated by a TRIM code (112.5±19nm). Amorphous and nanocrystalline composite structure with a thickness of about 50nm was found in the surface layer of Nb-implanted coatings by HRTEM, and the nanocrystalline with a size of about 5–10nm was distributed in amorphous structure. The analysis of GIXRD showed that after Nb ion implantation, the TiAlN peaks shifted toward the high 2θ angle side and became broad as a result of lattice distortion and a new phase of NbN was formed. The microhardness of the coatings after Nb ion implantation increased remarkably, whereas the friction coefficient had no significant improvement. Wear loss and wear area of TiAlN coatings were significantly reduced with increasing dose of implanted Nb ion.