Increasing Sb Content Research Articles

Microwave dielectric properties of Ba3LiNb3 − xSbxTi5O21(x = 0–3) ceramics

The single phase Ba3LiNb3−xSbxTi5O21 (x=0–3) solid solution system has been synthesized by the conventional solid-state ceramic route, and the effect of Sb substitution for Nb on structure and microwave dielectric properties has also been investigated. The ceramics were well sintered at the temperatures ranging from 1100°C to 1220°C for 4h. The microwave dielectric properties of these ceramics show a linear variation between the end members for all compositions, and Sb substitution effectively improved the quality factor and modified τf. With the increasing Sb content, the dielectric constant (εr) decreased from 78 to 27, the Q×f value enhanced significantly from 9800 to 29,400GHz, and τf improving from 205ppm/°C to −25ppm/°C.

Magnetic properties and magnetocaloric effect in Ni0.5Mn0.5−xSb x alloys

Ni0.5Mn0.5−x Sb x (x = 0.1, 0.2, 0.3, and 0.4) ingots fabricated by arc-melting high-pure metals have been studied to determine their structure and magnetic properties and to identify the magnetocaloric effect. X-ray diffraction analyses reveal that the sample with x = 0.2 is close to a single phase in a cubic structure while the others have the secondary phases. This influences strongly the magnetic properties of Ni0.5Mn0.5−x Sb x . With increasing Sb content, the Curie temperature (T C ) increases from ∼210 (for x = 0.1) to 435 K (for x = 0.4). Among the studied alloys, two samples, x = 0.2 and 0.3, have the greatest saturation magnetization values, which were recorded at 300 K. Under an applied field of 12.0 kOe, the maximum magnetic entropy changes are about 1.0 and 0.5 J.kg−1·K−1 for x = 0.2 and 0.3, respectively. Detailed analyses related to isothermal M-H curves in the vicinity of T C by using the modified Arrott method reveal that these samples undergo a second-order phase transition with critical exponents of β = 0.40 ± 0.01 and γ = 1.27 ± 0.08 for x = 0.2 and of β = 0.69 ± 0.09 and γ = 0.85 ± 0.10 for x = 0.3. The differences in the critical parameters are likely related to the presence of Ni-related secondary phases.

Electronic Structure and Optical Properties of Antimony-Doped SnO2 from First-Principle Study

A first-principles study has been performed to calculate the electronic and optical properties of the SbxSn1−xO system. The simulations are based upon the method of generalized gradient approximations with the Perdew—Burke—Ernzerhof form in the framework of density functional theory. The supercell structure shows a trend from expanding to shrinking with the increasing Sb concentration. The increasing Sb concentration induces the band gap narrowing. Optical transition has shifted to the low energy range with increasing Sb concentration. Other important optical constants such as the dielectric function, reflectivity, refractive index, and electron energy loss function for Sb-doped SnO2 are discussed. The optical absorption edge of SnO2 doped with Sb also shows a redshift.

Doping effects of Li–Sb content on the structure and electrical properties of [(Na 0.5K 0.5) 1 − x(Li) x(Sb) x(Nb) 1 − xO 3] lead-free piezoelectric ceramics

Ceramic samples of [Na 0.5K 0.5] 1 − x (Li) x (Sb) x (Nb) 1 − x O 3 (NKNLS) ( x = 0.04–0.06) were prepared by high temperature solid-state reaction method. X-ray diffraction analysis of the powder samples suggests the formation of a single-phase material with transformation from orthorhombic to tetragonal crystal structure with increase in Sb content. Dielectric studies show a diffuse phase transition about 100 °C and another phase ferroelectric–paraelectric transition at 330 °C. Polarization vs. electric field ( P– E) hysteresis studies show maximum remanent polarization ( Pr ∼ 0.66 C m −2) for composition x = 0.05. AC conductivity in the compound increases with increase in temperature which may be attributed due to oxygen vacancies and show negative temperature coefficient of resistance (NTCR) effect.

Compositional dependence optical properties study of As40Se60 − xSbx thin films

Thin films were thermally evaporated from the bulk glasses of As40Se60−xSbx (with x=0, 5, 10, 15at.%) under high vacuum. We have characterized the deposited films by Fourier Transform Infrared spectroscopy. The relationship between the structural and optical properties and the compositional variation has been investigated. Increasing Sb content was found to affect the thermal and optical properties of these films. Non-direct electronic transition was found to be responsible for the photon absorption inside the investigated films. It was found that, the optical band gap Eo decreases while the width of localized states (Urbach energy) Ee increases.

Effects of Sb content on microstructure and mechanical properties of Mg-6Zn-Y-Zr- xSb alloy

Effects of Sb content on microstructure and mechanical properties of Mg-6Zn-Y-Zr- xSb alloy were investigated by OM, SEM, XRD and mechanical property test. The results indicate that addition of Sb can break continuous network structure into particles in the interdendritic spaces, and with increasing Sb content, the volume fraction of these particles increases. The as-cast microstructure of the alloy with low content of Sb consists of α-Mg, Zn-rich phase, eutectic structure (α-Mg+ I-phase) and YSb. With increasing Sb content, Mg 3Sb 2 and Mg 4Zn 7 phases appear, while I-phase disappears finally. The ultimate tensile strength and elongation increase first with the increase of Sb content, while the mechanical properties reduce at excessive Sb content.

Optical studies of (AsSe)100−x Sb x thin films

Thin arsenic-selenium-antimony films (AsSe)100−x Sb x (x=0,5,10,15 mol.%) have been deposited on glass substrates by vacuum thermal evaporation (VTE) and pulsed laser deposition (PLD) techniques from the corresponding bulk glassy materials. The refractive index and the film thickness have been determined from the optical transmission spectra by modified Swanepoel method. The optical band gap calculated using the Tauc’s approximation showed a narrowing as a function of the increased Sb content from 1.74 eV to 1.53 eV in the VTE films and from 1.64 eV to 1.42 eV in the PLD films. The refractive index of the Sb-doped films strongly increased with the Sb content and reached the largest value for the PLD films. The results verify that both techniques are suitable for deposition of thin glassy films with high optical quality.

Structural Rigidity, Percolation and Transition-Temperature Study of the Ge<sub>19</sub>Se<sub>81-x</sub>Sb<sub>x</sub> System

Selenium-based glasses are attractive candidate materials because of their low transmission losses and other optical properties. In the present paper, samples of Ge19Se81-xSbx (x = 0, 4, 8, 12, 16, 17.2, 20) were prepared by using the melt-quench technique, and their X-ray diffraction spectra were studied. Some of the physical parameters were calculated theoretically. It was observed that the glass transition temperature increased up to x = 17.2 and then decreased whereas the theoretically calculated band-gap decreased with increasing Sb content.

Thermoelectric Properties of Sb-doped Mg2Si Prepared by Solid-State Synthesis

Sb-doped Mg2Si was prepared by solid-state synthesis and thermoelectric properties were examined. All the Sb-doped Mg2Si compounds showed n-type conduction, indicating that the electrical conduction is mainly due to electrons. The electrical conductivity significantly increased and the absolute value of Seebeck coefficient decreased with increasing Sb content because electron concentration considerably increased from ~1016 to ~1020 cm−3 by Sb doping. The thermal conductivity did not changed significantly by Sb doping. The maximum value of thermoelectric figure-of-merit of 0.62 was obtained for Mg2Si:Sb0.02 at 823 K.

InP‐based InGaAsSbN quantum well laser diodes in the 2‐μm wavelength region

AbstractInGaAsSbN quantum well (QW) laser diodes on InP in the 2‐μm wavelength region were grown by molecular beam epitaxy (MBE). It was found that an increase in Sb content improved the properties of InGaAsSbN QW laser diodes. We observed electroluminescence at 4.51 μm at room temperature for InAsSbN SQ laser diodes, and laser operation at 2.31 μm at 190 K. Annealing effects were also studied. © 2011 Wiley Periodicals, Inc. Electron Comm Jpn, 94(5): 33–38, 2011; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/ecj.10195

Optical band gap, refractive index dispersion and single-oscillator parameters of amorphous Se70S30−xSbx semiconductor thin films

The optical band gap, refractive index and oscillator parameters of amorphous semiconductor Se70S30− x Sb x thin films with x = 0, 18, 12 and 30 at. % deposited by electron-beam evaporation were investigated by optical spectrophotometry. The energy gap decreases from 2.25 to 1.08 eV with increasing Sb content introduced at the expense of S, which is explained in terms of chemical bond and cohesive energy approaches. The method proposed by Swanepoel is applied to extract the refractive index n. It was found that the refractive index is strongly related to the change in the concentration of Sb, which is related to the increase density of the film material with increasing Sb content, and is interpreted in terms of polarisability and the mean coordination number. The ratio of the refractive indices of (Se70Sb30)/(Se70S30) is ≈ 1.32 at a wavelength λ ≈ 1600 nm and increases to 1.48 at λ ≈ 950 nm. Such a refractive index contrast could be used to fabricate a distributed Bragg reflector (DBR) stack with limited number of layers. The dispersion of the refractive index is discussed in terms of the Wemple–DiDomenico single-oscillator model. The oscillator parameters, i.e. the single-oscillator energy Eo , the dispersion energy Ed , the static refractive index n 0, the average interband oscillator wavelength λ 0, and the average oscillator strength S o, and the optical conductivity have been estimated.

Interface between Sn–Sb–Cu solder and copper substrate

Influence of antimony and copper in Sn–Sb–Cu solder on the melting and solidification temperatures and on the microstructure of the interface between the solder and copper substrate after wetting the substrate at 623 K for 1800 s were studied. Microstructure of the interface between the solder and copper substrates in Cu–solder–Cu joints prepared at the same temperature for 1800 s was observed and shear strength of the joints was measured. Influence of the atmosphere – air with the flux and deoxidising N 2 + 10H 2 gas – was taken into account. Thermal stability and microstructure were studied by differential scanning calorimetry (DSC), light microscopy, scanning electron microscopy (SEM) with energy-dispersive spectrometry (EDS) and X-ray diffraction (XRD). Melting and solidification temperatures of the solders were determined. An interfacial transition zone was formed by diffusion reaction between solid copper and liquid solder. At the interface Cu 3Sn and Cu 6Sn 5 phases arise. Cu 3Sn is adjacent to the Cu substrate and its thickness decreases with increasing the amount of copper in solder. Scallop Cu 6Sn 5 phase is formed also inside the solder drop. The solid solution Sn(Sb) and SbSn phase compose the interior of the solder drop. Shear strength of the joints measured by push-off method decreases with increasing Sb concentration. Copper in the solder shows even bigger negative effect on the strength.

Carrier Doping in the Type VIII Clathrate Ba8Ga16Sn30 Through Sb Substitution

The type VIII clathrate Ba8Ga16Sn30 has a relatively high figure of merit (ZT) from 200°C to 400°C. Our previous calculations showed that the optimum carrier concentration for high ZT is on the order of 1020/cm3 for both p- and n-type samples. The ZT value exceeds unity for the n-type material. However, actual carrier concentrations for synthesized samples were on the order of 1019/cm3. With the aim of increasing the carrier concentration, we have synthesized single crystals of Sb-doped Ba8Ga16Sn30. Contrary to our expectation, the Ga content in the crystal increased with the increase in Sb content. In both p- and n-type samples, the carrier concentration was increased, and the power factor for the p-type samples was improved to 1.4 × 10−2 W/mK2. These results are discussed in relation to the change in the band structure.

Preparation and electrical properties of perovskite ceramics in the system BaBi 1− xSb xO 3 (0 ≤ x ≤ 0.5)

The effect of the composition on the electrical properties of BaBi 1− x Sb x O 3 (0 ≤ x ≤ 0.5) negative temperature coefficient (NTC) thermistors was studied. Major phases present in the sintered bodies of BaBi 1− x Sb x O 3 (0 < x < 0.5) ceramics were BaBi 0.5Sb 0.5O 3 compounds with a rhombohedral structure and BaBiO 3 compounds with a monoclinal structure. Most pores were located in the grains of BaBiO 3 and BaBi 0.5Sb 0.5O 3 ceramics. It was apparent that the ρ 25 and B 25/85 constant of the thermistors increased with increasing Sb content.

The effect of Sb content on glass-forming ability, the thermal stability, and crystallization of Ge–Se chalcogenide glass

The glass formation and devitrification of intermediate alloys in the Sb-Ge-Se system were studied by differential scanning calorimetry. A comparison of various simple quantitative methods to assess the level of stability of the glassy materials in the bove mentioned system is presented. All of these methods are based on characteristic temperatures, such as the glass transition temperature, Tg, the onset temperature of crystallization, Tin, the temperature corresponding to the maximum crys- tallization rate, Tp, or the melting temperature, Tm. In this case, kgl may be more suitable for estimating the glass thermal stability in above composition range than XT. In this work the parameter Kr(T) is added to the stability criteria. The thermal stability of some ternary compounds of the Sb-Ge-Se type has been evaluated experimentally and correlated with the activation energies of crystalliza- tion by this kinetic criterion and compared with those evaluated by other criteria. All the results of criteria and kinetic parameter Kr(T) confirm that the thermal stability decrease with increasing Sb content in the glassy system. The crystallization results are analyzed and both the acti- vation energy of crystallization process and the crystalli- zation mechanism are characterized. Finally, identification of the crystalline phases was made by recording the X-ray diffraction pattern of the transformed material. This pattern shows the existence of microcrystallites of two phases, the first is germanium Selenide GeSe2 and the second is Sb2Se3 in amorphous matrix for annealed of Sb2.5Ge22.5Se75 and Sb10Ge15Se75 glass.

Effect of antimony on vigorous interfacial reaction of Sn–Sb/Te couples

A vigorous reaction between molten Sn–Sb solder and Te substrate leads to a thick SnTe–Sn mixture layer at the soldered junction. The effect of Sb addition in Sn on the kinetics of Sn–Sb/Te interfacial reaction and formation of SnTe–Sn reaction layer is reported. Sb element was found to expedite the growth of SnTe–Sn reaction layer in the Sn–Sb/Te couples dramatically. With increasing Sb content in Sn–Sb solder, the growth rate of SnTe–Sn reaction layer increases while both the size of SnTe grains and the fraction of Sn in SnTe–Sn decrease. The thickness of SnTe–Sn layer follows a parabolic law with reaction time for Sn–Sb/Te couples, unlike the linear dependence with time for Sn/Te couples. An apparent diffusivity of 2 × 10 −7 cm 2/s was determined for Sn transport through the SnTe–Sn layer in the Sn–Sb/Te couples reacting at 250 °C.

Influence of Sintering Temperature on Densification, Structure and Microstructure of Li and Sb Co-Modified (K,Na)NbO&amp;lt;sub&amp;gt;3&amp;lt;/sub&amp;gt;-Based Ceramics

Polycrystalline samples of Lead free (K0.5Na0.5)1-x(Li)x(Sb)x(Nb)1-xO3 ceramics with nominal compositions (x = 0.040 to 0.060) have been prepared by high temperature solid state reaction technique. X-ray diffraction (XRD) pattern shows that the crystal structure transforms from orthorhombic to tetragonal as Li and Sb content increases. Normal sintering process yield compounds with density ~98.2% of the theoretical value. Densification of the Li and Sb co-doped KNN ceramics might be explained by the liquid-phase sintering. This may be attributed to the low melting temperature of Li compounds that appears to promote the formation of a liquid phase during sintering.

Evolution of cobalt spin states and magnetic coupling along the SrCo1−xSbxO3−δ system: correlation with the crystal structure

The oxides of the SrCo(1-x)Sb(x)O(3-δ) perovskite family have been recently designed, characterized and described as cathode materials for solid-oxide fuel cells with competitive power performance in the temperature range 750-850 °C. They feature a number of interesting properties including a good electronic conductivity, low electrode polarization resistance and adequate thermal expansion; the crystal structure adopts a 3C corner-linked perovskite network with a considerable number of oxygen vacancies. This paper reports on the effects of Sb-doping on the crystal structure features, the Co oxidation state and magnetic properties related to the presence of spin-state transitions in the Co cations. A phase transition was observed from the tetragonal P4/mmm space group for x≤ 0.15 to the cubic Pm ̅3m space group in the x = 0.2 composition from neutron powder diffraction data. For the tetragonal phases the oxygen vacancies were found to be ordered and localized in the axial O2 and equatorial O3 atoms surrounding the Co2 positions. A noticeable distortion of CoO(6) octahedra is observed for x = 0.05 and 0.1, exhibiting a charge-ordering with a mixed oxidation state of Co(3+/4+) at Co1 sites and Co(3+) at Co2 positions: the Jahn-Teller Co(3+) in an intermediate-spin configuration is responsible for the octahedral distortion. Increasing Sb contents promotes a higher average oxidation state of cobalt, from a valence of 3.2+ for x = 0.05 to 3.4+ for x = 0.2, inducing a decrease of the oxygen vacancies and favouring a random distribution over a Pm ̅3m cubic symmetry. All the samples present an antiferromagnetic behaviour with a G-type (k = 0) magnetic structure. The increase of the Sb content induces the weakening of the crystal field (Δ(cf)) in the octahedral environment promoting the Co spin-transition from the intermediate-spin to the high-spin configuration, as evidenced by the decrease of the octahedral distortion, increment of the unit-cell volume and enhancement of the ordered magnetic moment.

Structural analysis and properties of thermally stable Ba 8Mg(Nb 6− xSb x)O 24 microwave ceramics

Ba 8Mg(Nb 6− x Sb x )O 24 ( x = 0, 0.3, 0.6, 0.9, 1.2, 1.5, 1.8 and 2.4) ceramics were prepared through conventional solid-state route. The materials were calcined at 1200 °C and sintered at the optimized temperature of 1375 °C. The structure of the system was analyzed by X-ray diffraction, Fourier transform infrared and Raman spectroscopic methods. The theoretical and experimental densities were calculated. The dielectric constant ( ɛ r), temperature coefficient of resonant frequency ( τ f) and the unloaded quality factor ( Q u) were measured in the microwave frequency region using cavity resonator method. The τ f values of the samples reduced considerably with the increase in Sb concentration. The dielectric responses were studied in the frequency range 50 Hz to 5 MHz also. The microstructure of the sintered pellets was analyzed using scanning electron microscopy. The materials have intense emission lines in the visible region. The compositions have good microwave dielectric properties and photoluminescence and hence are suitable for dielectric resonator and ceramic laser applications.

Structural, morphological and optical properties of Bi 2− xSb xSe 3 thin films grown by electrodeposition

Ternary single-phase Bi 2− x Sb x Se 3 alloy thin films were synthesized onto Au(1 1 1) substrates from an aqueous solution containing Bi(NO 3) 3, SbCl 3, and SeO 2 at room temperature for the first time via the electrodeposition technique. The electrodeposition of the thin films was studied using cyclic voltammetry, compositional, structural, optical measurements and surface morphology. It was found that the thin films with different stoichiometry can be obtained by controlling the electrolyte composition. The as-deposited films were crystallized in the preferential orientation along the (0 1 5) plane. The SEM investigations show that the film growth proceeds via nucleation, growth of film layer and formation of spherical particles on the film layer. The particle size and shape of Bi 2− x Sb x Se 3 films could be changed by tuning the electrolyte composition. The optical absorption spectra suggest that the band gap of this alloy varied from 0.24 to 0.38 eV with increasing Sb content from x = 0 to x = 0.2.