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Ni${}_{0.65-x}$Zn${}_{0.35}$Mg${}_x$Fe₂O₄ ($0\le x\le 0.2$) with lower compositions of magnesium were synthesized by the sol–gel method and sintered at 1080${}^{\circ }$C for 4 h. X-ray diffraction (XRD) patterns suggest the single phase nature of the spinel-type ferrite and increase in lattice parameter for increasing magnesium content. Surface morphology reveals that grain size increases with increasing magnesium concentration. Magnesium substitution in Ni–Zn ferrites showed influence on the interatomic distance for tetrahedral A sites and octahedral B sites calculated using the standard formula. Conductivity along with dielectric measurements gives additional information on the transport mechanism for magnesium substitution in Ni–Zn ferrites calculated at lower frequencies. Both magnetic loss and dielectric loss were investigated at lower frequency to understand the losses associated with domain wall contribution for magnesium-substituted Ni–Zn ferrites.

In this paper, we report on microstructural, optical and electrical properties of alternating multilayer of vanadium pentoxide (V₂O₅), 25 nm, and vanadium (V), 5 nm, thin films deposited at room temperature by radio frequency (RF) and DC magnetron sputtering, respectively. Raman and photoluminescence (PL) spectroscopy have been employed to investigate the effects of thermal annealing for 20, 30 and 40 min at 400${}^{\circ }$C in Nitrogen (N₂) atmosphere on the multiple phase formation and its impact on the film resistance and temperature coefficient of resistance (TCR). We demonstrate that the oxygen free annealing environment allows the formation of multiple phases including V₂O₅, V₆O${}_{13}$ and VO₂ through oxygen diffusion and consequent deficiency in V₂O₅ layer.

A carbon precursor film was formed on a titanium plate by a hydrothermal method using glucose, and an amorphous film was obtained by carbonization at 400^∘C under an Ar atmosphere. The morphology and composition of the surface was analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS), and the interface contact resistance (ICR) under different pressures by simulating the working mode of the fuel cell. The corrosion resistance of amorphous carbon coatings was tested by simulating the proton exchange membrane fuel cells (PEMC). The amorphous coating showed excellent interfacial conductivity and great corrosion resistance, with high potential application in bipolar plates of PEMFCs

In this paper, dielectric properties of Ni_xMn_0.4-xZn_0.6Fe₂O₄ ferrites with x varying from 0.05 to 0.35 prepared by the citrate precursor method have been investigated as a function of frequency, temperature, composition, and sintering temperature. A decrease in the dielectric constant is observed with the increase in Ni concentration except for x = 0.3. This decrease in dielectric constant with the increase in Ni concentration is justified by inverse proportionality between resistivity and dielectric constant. Dispersion in the dielectric constant with frequency in the range of 75 Hz to 30 MHz is observed. Resonance peaks were observed in tan δ_ε versus frequency curve for all the samples. A shift in the resonance frequency toward higher frequency is observed with the increase in temperature. The peak height also increases with an increase in temperature. Phase change is confirmed by differential scanning calorimetry. Structural studies have been done by X-ray diffraction technique and scanning electron microscopy. Possible theories, models, and mechanisms contributing to these processes have been discussed.

Polycrystalline cobalt substituted Ni–Zn ferrite with composition Ni_0.65-xCo_x Zn_0.35Fe₂O₄(x = 0.00–0.25 insteps of 0.05) have been prepared through the conventional solid state ceramic method. Calcination and sintering have been performed in air atmosphere at 950°C and 1250°C for 4 h and 2 h, respectively followed by natural cooling to room temperature. X-ray diffraction patterns of all samples indicated the formation of the single spinel structure and the accurate lattice parameter for each composition has been determined using the Nelson–Riley error function. The increase in lattice constant on cobalt substitution is attributed to the ionic radius difference between the displaced and the substituted ion. The variation in lattice constant on incorporation of Co²⁺ ion indicates its solubility into the spinel lattice and noticeable modification in structural properties have been observed. The observed increase in the saturation magnetization and Curie temperature with the increase in the Co²⁺ substitution is due to its higher magnetic moment compared to that of Ni²⁺, improvement in the A–B exchange interaction mechanism and large positive contribution to magnetic anisotropy due to presence of Co²⁺ when they are at the octahedral sites. The observed variation in the initial magnetic permeability and the magnetic loss factor with cobalt substitution measured at a low frequency of 1 KHz have been attributed to the modification in the density, porosity, grain size and anisotropy contributions. A nearly comparable variation is observed in the room temperature dc electrical resistivity and activation energy for conduction and is attributed to the modification in structure, role and nature of cobalt ions and the microstructure aspects like grain size and pore concentration. The activation energy values in the range of 0.28 to 0.36 eV suggest a possible electron hopping. The observed changes in the structural and the magnetic and electrical properties have all been discussed in the light of exiting understanding.

Antimony-doped tin oxide (SnO₂:Sb, ATO) films were deposited on 7059 corning glass substrate by radio frequency magnetron sputtering method using a commercial ceramic target with a mixture of SnO₂ and Sb (6 wt.%) for application to transparent electrodes. The ATO film was deposited at working pressure of 5 mTorr and RF power of 175 W without substrate heating. The thickness of the deposited ATO films was about 150 nm using a surface profiler (alpha-step). The films were annealed at temperatures ranging from 300 to 600°C in step of 100°C using RTA equipment in vacuum and oxygen atmosphere, respectively. We investigated the effects of the post-annealing atmospheres on structural, electrical and optical properties of the ATO films. The results show that the increase of the annealing temperature improved the crystallinity of the ATO films, increased the grain size and improved electrical and optical properties, regardless of annealing atmospheres. The resistivity of the ATO films decreased significantly with higher annealing temperatures in vacuum and oxygen atmosphere. In the visible range from 400 to 800 nm, the optical transmittance of the ATO films increased over 90% at higher annealing temperature.

The resistivities along c-axis ρ_c(H, T) of ErNi₂ B₂C have been measured with H_⊥ and H_‖c-axis for 2 < T < 300 K and the superconducting upper critical field H_c2(T) curves of ErNi₂B₂C were constructed for each magnetic fields. Our H_c2(T) curves have been compared and discussed with those from ρ_ab(H, T) measurements which explain the anisotropy and its temperature dependence of H_c2(T) are thought to arise from magnetic pair breaking and the anisotropic field dependence of Néel temperature T_N originated from Er⁺³ sublattice.

Indium Oxide quasi one-dimensional (1D) nanostructures known as nanowires and nanorods synthesis using the thermal evaporation method, has been articulated. To nucleate growth sites, substrate seeding promoted 1D nanostructures growth. The catalyst-mediated growth mechanism showed more favorable morphologies and physical properties in under vacuum conditions associated with bottom-up technique. Scanning electron microscopy (SEM) results showed that the Zn-doped 1D nanostructures had spherical caps. The X-ray diffraction (XRD) pattern and energy-dispersive X-ray (EDX) spectrum indicated that these caps intensively associated with ZnO. Therefore, it was reasonable that the vapor–liquid–solid mechanism (VLS) was responsible for the growth of the In₂O₃-ZnO heterostructure nanowires. This technique enhances optical and electrical properties in nanostructures. The photoluminescence (PL) analysis in Zn-doped In₂O₃ nanowires and nanorods shows that the intensity of the visible and UV-region emissions overwhelmingly increases and resistance measurement professes the improvement of linear conductance in VLS growth mechanism.

In this paper we report influence of titanium substitution on the structural properties and d.c. conduction behavior of Li-Zn ferrites. The samples having the compositional formula Li_0.45+0.5tZn_0.1Ti_tFe_2.45-1.5tO₄ with t varying from 0 to 1.2 in steps of 0.2 were prepared by the conventional dry ceramic method. XRD analysis showed all the samples to be single phase spinel and the lattice parameter was found to increase with increasing t. D.C. resistivity increases with Ti concentration. The possible mechanisms involved are discussed.

Samples of series Bi_1.6Pb_0.4Sr₂Ca₂Cu_3-xZn_xO_10-δ with x = 0.0, 0.015, 0.03, 0.06, 0.09 and 0.12 are synthesized by solid-state reaction route. All the samples crystallize in tetragonal structure with majority (> 90%) of Bi-2223(Bi₂Sr₂Ca₂Cu₃O₁₀) phase (c-lattice parameter ~ 36 Å). The proportion of Bi-2223 phase decreases slightly with an increase in x. The lattice parameters a and c of main phase (Bi-2223) do not change significantly with increasing x. Superconducting critical transition temperature (T_c) decreases with x as evidenced by both resistivity [ρ(T)] and ac magnetic susceptibility [χ(T)] measurements. Interestingly the decrement of T_c is not monotonic and the same saturates at around 96 K for x > 0.06. In fact T_c decreases fast (~ 10 K/at%) for x = 0.015 and 0.03 samples and later nearly saturates for higher x values. Present results of Zn doping in Bi-2223 system are compared with other Zn-doped HTSC (high temperature superconducting) systems, namely the RE-123 (REBa₂Cu₃O₇) and La-214 ((La, Sr)₂CuO₄).

Indium tin oxide (ITO) nanoparticles were synthesized by co-precipitation method using ammonia as a precipitator in absence/presence of various surfactants (LABS and Triton X-100). The synthesized nanoparticles were investigated by scanning electron microscopy, resistance measurement, photoluminescence (PL) spectroscopy and X-ray diffractometry (XRD) techniques. The XRD patterns of nanoparticles were also studied by Rietveld refinement method for calculation of crystallite size, micro-strain and lattice parameter. The results indicate that by application of LABS and Triton X-100 as surfactant the particle size was increased. Two luminescence bands were observed in PL spectra of ITO nanoparticles with the excitation energy lower than their band gaps. It was found that the ratios of luminescence bands have relation with resistances and colors of ITO nanoparticles. In addition, the band structure of ITO nanoparticles was described considering the obtained results.

Molybdenum thin films were sputter deposited under different conditions of DC power and chamber pressure. The structure and topography of the films were investigated using AFM, SEM and XRD techniques. Van der Pauw method and tape test were employed to determine electrical resistivity and interfacial strength to the substrate, respectively. All the films are of sub-micron thickness with maximum growth rate of 78 nm/min and crystallite size in the range of 4 to 21 nm. The films produced at high power and low pressure exhibit compressive residual strains, low electrical resistivity and poor adhesion to the glass substrate, whereas the converse is true for films produced at high pressure.

Cadmium sulfide (CdS) and aluminum-doped zinc oxide (Al:ZnO) thin films are used as buffer layer and front window layer, respectively, in thin film solar cells. CdS and Al:ZnO thin films were produced using chemical bath deposition (CBD) and sol–gel technique, respectively. For CBD CdS, the effect of bath composition and temperature, dipping time and annealing temperature on film properties was investigated. The CdS films are found to be polycrystalline with metastable cubic crystal structure, dense, crack-free surface morphology and the crystallite size of either few nanometers or 12–17 nm depending on bath composition. In case of CdS films produced with 1:2 ratio of Cd and S precursors, spectrophotometer studies indicate quantum confinement effect, owing to extremely small crystallite size, with an increase in E_g value from 2.42 eV (for bulk CdS) to ~ 3.76 eV along with a shift in the absorption edge toward ~ 330 nm wavelength. The optimum annealing temperature is 400°C beyond which film properties deteriorate through S evaporation and CdO formation. On the other hand, Al:ZnO films prepared via spin coating of precursor sols containing 0.90–1.10 at.% Al show that, with an increase in Al concentration, the average grain size increases from 28 nm to 131 nm with an associated decrease in root-mean-square roughness. The minimum value of electrical resistivity, measured for the films prepared using 0.95 at.% Al in the precursor sol, is ~ 2.7 × 10^-4 Ω ⋅ cm. The electrical resistivity value rises upon further increase in Al doping level due to introduction of lattice defects and Al segregation to the grain boundary area, thus limiting electron transport through it.

In this research, influence of adding Li₂CO₃ (at 0%, 2%, 4%, 6%) on electrical and magnetic properties of ${\text{Ni}}_{0.6}$${\text{Mg}}_{0.4}$Fe₂O₄ (with 60% Ni and 40% Mg) ferrite has been studied. The samples are prepared by solid state reaction method and sintered at 1300^∘C for 6h. X-ray diffraction (XRD) patterns show the samples belong to single-phase cubic structure without any impurity phase. The magnetic properties (saturation magnetization and coercivity) of the samples have been investigated by VSM and found that the higher concentration of Li₂CO₃ reduces the hysteresis loss. DC resistivity increases with Li₂CO₃ contents whereas it decreases initially and then becomes constant at lower value with temperature which indicates that the studied samples are semiconductor. The dielectric dispersion occurs at a low-frequency regime and the loss peaks are formed in a higher frequency regime, which are due to the presence of resonance between applied frequency and hopping frequency of charge carriers. Notably, the loss peaks are shifted to the lower frequency with Li₂CO₃ additions.

Highly resistive Al₂O₃ ceramics have been widely used for electrostatic chucking of silicon wafer. However, there are some restrictions to use such chuck material on higher resistance substrates, such as glass or sapphire wafer. In this study, Al₂O₃ compositions were modified by various dopants ; TiO₂, CuO and SiO₂, and their sinterability, crystal structure, electrical properties and chucking property were investigated with different doping concentrations and sintering conditions. Both of TiO₂ and CuO were found to be key dopants on controlling the sintering temperature and electrical resistivity. When 2~3 mol% of TiO₂ and CuO, and 1mol% of SiO₂ were added simultaneously, the specimens having lowered resistivity, ~10¹² Ωcm were obtained at a relatively lowered sintering temperature, 1250°C, which means that the electrostatic chuck for display and LED sapphire chip processes can be economically fabricated by using simple ceramic process.