Fusion Diagrams in the \mathrm{BiBO}_{3}–\mathrm{YbBO}_{3} and \mathrm{Bi}_{4}\mathrm{B}_{2}\mathrm{O}_{9}–\mathrm{YbBO}_{3} Systems

A calculation model of the Gibbs energy of ternary oxide compounds from the binary components was used. Thermodynamic properties of \(\mathrm{Yb}_{2} \mathrm{O}_{3}\) – \(\mathrm{Bi}_{2}\mathrm{O}_{3}\) – \(\mathrm{B}_{2}\mathrm{O}_{3}\) ternary systems in the condensed state were calculated. Thermodynamic data of binary and ternary compounds were used to determine the stable sections. The probability of reactions between the corresponding components in the \(\mathrm{Yb}_{2} \mathrm{O}_{3}\) – \(\mathrm{Bi}_{2} \mathrm{O}_{3}\) – \(\mathrm{B}_{2} \mathrm{O}_{3}\) system was estimated. Fusibility diagrams of systems \(\mathrm{BiBO}_{3}\) – \(\mathrm{YbBO}_{3}\) and \(\mathrm{Bi}_{4} \mathrm{B}_{2} \mathrm{O}_{9}\) – \(\mathrm{YbBO}_{3}\) were studied by physical–chemical analysis. The isothermal section of the phase diagram of \(\mathrm{Yb}_{2} \mathrm{O}_{3}\) – \(\mathrm{Bi}_{2} \mathrm{O}_{3}\) – \(\mathrm{B}_{2} \mathrm{O}_{3}\) at 298 K is built, as well as the projection of the liquid surface of \(\mathrm{BiBO}_{3}\) – \(\mathrm{B}_{2} \mathrm{O}_{3}\) – \(\mathrm{YbBO}_{3}\) .     

Liquidus Temperatures and Thermodynamic Properties of the KCl–\mathrm{{KNO}}_{2}, NaCl–\mathrm{{NaNO}}_{2}, and \mathrm{{KNO}}_{2}–\mathrm {NaNO}_{2} Systems

Potassium nitrite is very sensitive to temperature, humidity, and the atmosphere, so few studies have been made in this field for the thermodynamic properties of molten salt with nitrite salt. In this article, the liquidus curves of NaCl– $\mathrm{{NaNO}}_{2}$ NaNO 2 , KCl– $\mathrm{{KNO}}_{2}$ KNO 2 , and $\mathrm {NaNO}_{2}$ NaNO 2 – $\mathrm{{KNO}}_{2}$ KNO 2 are calculated by a simple “hard-sphere” ionic interaction model. The calculated liquidus temperatures show good agreement with experimental values, which implies an ideal mixing enthalpy and entropy for the liquid binary systems. In addition to the phase equilibrium data and experimental thermochemical properties of molten salt systems, the activities of these binary systems are determined by the phase diagrams and the analytical integration of the classical Gibbs–Duhem equation.     

Magnetic Properties of Nanocrystalline Nickel–Cobalt Ferrites (\mathrm{Ni}_{1/2}{\mathrm{{Co}}}_{1/2}{\mathrm{{Fe}}}_{2}{\mathrm{O}}_{4})

In this study, the nanocrystalline nickel–cobalt ferrites $(\mathrm{Ni}_{1/2}\mathrm{Co}_{1/2}\mathrm{Fe}_{2}\mathrm{O}_{4})$ were prepared via the citrate route method at $27\,^{\circ }\mathrm{C}$ . The samples were calcined at $300\,^{\circ }\mathrm{C}$ for 3 h. The crystalline structure and the single-phase formations were confirmed by X-ray diffraction (XRD) measurements. Prepared materials showed the cubic spinel structure with m3m symmetry and Fd3m space group. The analyses of XRD patterns were carried out using POWD software. It gave an estimation of lattice constant “ $a$ ” of 8.3584 Å, which was in good agreement with the results reported in JCPDS file no. 742081. The crystal size of the prepared materials calculated by Scherer’s formula was 27.6 nm and the electrical conductivity was around $10^{-5}~\mathrm{S}\,\cdot \, \mathrm{m}^{-1}$ . The permeability component variations with frequency were realized. The magnetic properties of the prepared materials were analyzed by a vibrating sample magnetometer (VSM). It showed a saturation magnetization of $27.26\,\mathrm{emu} \cdot \mathrm{m}^{-1}$ and the behavior of a hard magnet.     

Ab Initio Study of Structural,Electronic, and Magnetic Properties of $\mathrm {A}_{1-x}^{\text {III}}$MnxBVI: In1−xMnxS-Diluted Magnetic Semiconductor

First-principles density functional calculations on the new class of diluted magnetic semiconductor \(A_{1-x}^{III}{Mn}_{x}B^{VI}\) In_1?x Mn _x S for x =?0.25 and 0.5 are investigated to study the structural, electronic, and magnetic properties, employing the full-potential linearized augmented plane wave method. Electronic band structures and density of states revealed a half-metallic character of In_1?x Mn _x S and show the stability of anti-ferromagnetic states as compared with ferromagnetic states. The calculated exchange constants J _dd are in good agreement with experimental and theoretical results on magnetic properties of single crystalline \(\mathrm {A}_{1-x}^{\text {III}}{\text {Mn}}_{x}\mathrm {B}^{\text {VI}}\) in the anti-ferromagnetic case. Our predicated calculations on the s,p-d exchange constants N ₀ α and N ₀ β show that they are lower than in \(\mathrm {A}_{1-x}^{\text {II}}{\text {Mn}}_{x}\mathrm {B}^{\text {VI}}\) DMS. The local environment is found tetrahedral as in the II–VI DMS and other (III,Mn) VI compounds. The total magnetic moment for In_1?x Mn _x S for different concentrations is in accordance with the exact value 5 μ _B and comes mainly from impurity Mn. The local magnetic moments of Mn ions are reduced from their free space charges values due to the p-d hybridization which produces small magnetic moments on the nonmagnetic In and S sites. The Curie temperature of In_1?x Mn _x S is calculated within the mean field approximation and compared with other DMS systems.     

Measurement of Out-of-Plane Thermal Conductivity of Epitaxial $$\hbox {YBa}_{2}\hbox {Cu}_{3}\hbox {O}_{7-{\delta }}$$ Thin Films in the Temperature Range from 10 K to 300 K by Photothermal Reflectance

We measured the out-of-plane (c-axis) thermal conductivity of epitaxially grown \(\hbox {YBa}_{2}\hbox {Cu}_{3}\hbox {O}_{7-{\delta }}\) (YBCO) thin films (250 nm, 500 nm and 1000 nm) in the temperature range from 10 K to 300 K using the photothermal reflectance technique. The technique enables us to determine the thermal conductivity perpendicular to a thin film on a substrate by curve fitting analysis of the phase lag between the thermoreflectance signal and modulated heating laser beam in the frequency range from \(10^{2}\,\hbox {Hz}\) to \(10^{6}\,\hbox {Hz}\). The uncertainties of measured thermal conductivity of all samples were estimated to be within \({\pm }9\,\%\) at 300 K, \({\pm }12\,\%\) at 180 K, \({\pm }16\,\%\) at 90 K and \({\pm }20\,\%\) below 50 K. The experimental results show that the thermal conductivity is dependent on the thickness of the thin films across the entire temperature range. We also observed that the thermal conductivity of the present YBCO thin films showed \(T^{1.4}\) to \(T^{1.6}\) glass-like dependence below 50 K, even though the films are crystalline solids. In order to explain the reason for this temperature dependence, we attempted to analyze our results using phonon relaxation times for possible phonon scattering models, including stacking faults, grain boundary and tunneling states scattering models.     

Lattice Dynamical,Elastic and Thermodynamical Properties of III–V Semiconductor AlSb,GaSb and Their Mixed Semiconductor $$\hbox {Ga}_{\mathrm{1-x}}\hbox {Al}_{\mathrm{x}}\hbox {Sb}$$

A proposed eleven-parameter three-body shell model is used to study the lattice dynamical properties such as phonon dispersion relations along high symmetry directions, phonon density of states, variation of specific heat and Debye characteristic temperature with absolute temperature, elastic constants and related properties for III–V semiconductor AlSb, GaSb and their mixed semiconductor \(\hbox {Ga}_{\mathrm{1-x}}\hbox {Al}_{\mathrm{x}}\hbox {Sb}\) having zinc-blende structure. We found an overall good agreement with the available experimental and theoretical results available in the literature.     

Microwave dielectrics: solid solution,ordering and microwave dielectric properties of $$(1{-}x)\hbox {Ba}(\hbox {Mg}_{1/3}\hbox {Nb}_{2/3})\hbox {O}_{3}{-}x\hbox {Ba(Mg}_{1/8}\hbox {Nb}_{3/4})\hbox {O}_{3}$$ ceramics

The effect of Ba(\(\hbox {Mg}_{1/8}\hbox {Nb}_{3/4})\hbox {O}_{3}\) phase on structure and dielectric properties of \(\hbox {Ba(Mg}_{1/3}\hbox {Nb}_{2/3})\hbox {O}_{3}\) was studied by synthesizing \((1{-}x)\hbox {Ba(Mg}_{1/3}\hbox {Nb}_{2/3})\hbox {O}_{3}{-}x\hbox {Ba}(\hbox {Mg}_{1/8}\hbox {Nb}_{3/4})\hbox {O}_{3}\) (\(x = 0\), 0.005, 0.01 and 0.02) ceramics. Superlattice reflections due to 1:2 ordering appear as low as \(1000^{\circ }\hbox {C}\). \(\hbox {Ba}(\hbox {Mg}_{1/3}\hbox {Nb}_{2/3})\hbox {O}_{3}\) forms solid solution with \(\hbox {Ba}(\hbox {Mg}_{1/8}\hbox {Nb}_{3/4})\hbox {O}_{3}\) for all ‘x’ values studied until \(1350^{\circ }\hbox {C}\). Ordering was confirmed by powder X-ray diffraction pattern, Raman study and HRTEM. Ceramic pucks can be sintered to density \({>}92\%\) of theoretical density. Temperature and frequency-stable dielectric constant and nearly zero dielectric loss (tan \(\delta \)) were observed at low frequencies (20 MHz). The sintered samples exhibit dielectric constant (\(\varepsilon _{\mathrm{r}})\) between 30 and 32, high quality factor between 37000 and 74000 GHz and temperature coefficient of resonant frequency (\(\tau _{\mathrm{f}})\) between 21 and \(24\hbox { ppm }^{\circ }\hbox {C}^{-1}\).     

Climatic Chamber for Temperatures up to 180\,^{\circ }\mathrm{C} and Pressures up to 0.5 MPa

A new relative-humidity setup was developed for calibrating sensors in the temperature range from \(-40\,^{\circ }\mathrm{C}\) up to \(180\,^{\circ }\mathrm{C}\) and at pressures down to 700 hPa and up to 0.5 MPa. The setup is based on the chamber-in-chamber model: a small additional chamber is positioned inside a climatic chamber. While the climatic chamber is used to generate the air temperature, a pre-conditioned gas from outside the climatic chamber delivers the required humidity in the new pressure chamber. Validation of the setup at atmospheric pressure showed relative-humidity uncertainties of 0.2 %rh at 5 %rh over the whole temperature range and 0.4 %rh at 95 %rh for temperatures above \(0\,^{\circ }\mathrm{C}\) . Below \(0\,^{\circ }\mathrm{C}\) , the maximum uncertainty increases to 0.9 %rh due to the influence of the temperature homogeneity. The temperature uncertainty of the new setup is between \(0.10\,^{\circ }\mathrm{C}\) and \(0.21\,^{\circ }\mathrm{C}\) . Five commercially available relative-humidity sensors, of different type and manufacturer and all suitable for high temperatures, were calibrated in the new setup. The measurements showed deviations outside the stated specifications of the manufacturer and the need of traceable calibration facilities.     

Photoacoustic Spectroscopic Study of Optical Properties of $$\hbox {Cu}_{2}\hbox {GeTe}_{3}$$ in Temperature Range from 80 K to 300 K

We used photoacoustic spectroscopy to investigate the optical properties of \(\hbox {Cu}_{2}\hbox {GeTe}_{3}\). The temperature dependence of the bandgap energy was evaluated from optical absorption spectra obtained in the photon energy range of 0.76 eV to 0.81 eV between 80 K and 300 K. We used the empirical and semi-empirical models of Varshni, Viña, and Pässler to describe the observed bandgap shrinkage in this compound. The Debye temperature and effective phonon temperature of the compound were estimated to be approximately 227.4 K and 151.6 K, respectively. Thus, the temperature dependence of the bandgap is mediated by acoustic phonons.     

Effects of Zn doping concentration on resistive switching characteristics in Ag /La1−xZnxMnO$_{3}/\textit {p}^{\mathrm {+}}$-Si devices

Ag /La _{1 ?x} Zn _x MnO\(_{\mathbf {3}}\boldsymbol {/}\textit {p}^{\boldsymbol {+}}\)-Si devices with different Zn doping contents were fabricated through sol–gel method. The effects of Zn doping concentration on the microstructure of La _{1 ?x} Zn _x MnO ₃ films, as well as on the resistance switching behaviour and endurance characteristics of Ag /La _{1 ?x} Zn _x MnO\(_{\mathbf {3}}\boldsymbol {/}\textit {p}^{\boldsymbol {+}}\)-Si were investigated. After annealing at 600 ^° C for 1 h, the La _{1 ?x} Zn _x MnO ₃ (x = 0.1, 0.2, 0.3, 0.4, 0.5) are amorphous and have bipolar resistance characteristics, with R _{H R S} / R _{L R S} ratios >10 ³ . However, the endurance characteristics show considerable differences; x= 0 . 3 shows the best endurance characteristics in more than 1000 switching cycles. The conduction mechanism of the Ag /La _{1 ?x} Zn _x MnO\(_{\mathbf {3}}\boldsymbol {/}\textit {p}^{\boldsymbol {+}}\)-Si is the Schottky emission mode at high resistance state. However, the conduction mechanism at low resistance state varies with Zn doping concentration. The dominant mechanism at x= 0 . 1 is filamentary conduction mechanism, whereas that at x ≥ 0 . 2 is space-charge-limited current conduction.     

Inter-laboratory Comparison of Impedance-Type Hygrometer in the Range from 10 % to 95 % at 5\,^{\circ }\hbox {C} to 55\,^{\circ }\hbox {C}

Traceability in the field of relative humidity (RH) measurements is typically assured indirectly through dew point and temperature scales. Conducting an inter-laboratory comparison at the national metrology institute (NMI) level, using a direct approach with a precision RH hygrometer as a transfer standard would, therefore, be of a particular interest, especially if the measurement setups were of a different type. This paper presents an RH comparison at the NMI level between the National Metrology Institute of South Africa (NMISA) and University of Ljubljana, Faculty of Electrical Engineering, Laboratory of Metrology and Quality (MIRS/UL-FE/LMK). In scope of this inter-comparison, calibration of an impedance-type hygrometer in the range from 10 %rh to 95 %rh at air temperatures of \(5\,^\circ \hbox {C}\) , \(25\,^\circ \hbox {C}\) , and \(55\,^\circ \hbox {C}\) , respectively, was performed. It was recommended that the participants use their standard procedure for the calibration of RH sensors and, at the same time, follow the specific criteria of the review protocol for uncertainty estimation accepted by Bureau International des Poids et Mesures (BIPM), marked as BIPM CCT-WG8/CMC-10. An interesting part of the comparison was the two different calibration methods which were used by the two partners and which also have different traceability routes. MIRS/UL-FE/LMK calibrated the sensor in the humidity generator by comparison against the reference chilled mirror hygrometer, which is traceable to the MIRS/UL-FE/LMK primary dew-point generator. NMISA calibrated the transfer standard against certified salt solutions, which were kept in a temperature-controlled chamber. Results showed acceptable agreement at all 15 calibration points.     

A New Co–C Eutectic Fixed-Point Cell for Thermocouple Calibration at 1324\,^{\circ }\mathrm{C}

The eutectic Co–C is a promising system to serve as a thermometric fixed point beyond the freezing point of copper ( \(1084.62\,^{\circ }\mathrm{C}\) ). Some national metrology institutes have developed, characterized, and compared their Co–C fixed-point cells based on conventional designs. Indeed, the fixed-point cells constructed are directly inspired by the technologies applied to the fixed points of the ITS-90 to the lower levels of temperature. By studying the eutectic metal–carbon systems, is appears that the high temperatures of implementation give a set of difficulties, such as the strong mechanical stresses on the graphite crucibles, due to the important thermal expansion of the eutectic alloys during their phase transitions. If these devices are suitable with research activities to serve like primary standards, it is not envisaged to propose them for a direct application to the calibration activities for the industry. As regards the limited robustness of the conventional fixed-point cells constructed, an intensive use of these device would not be reasonable, in term of cost for example. In this paper, a new Co–C fixed-point design is introduced. This low cost device has been developed specifically for intensive use in thermocouple calibration activities, with the aim of achieving the lowest level of uncertainties as is practicable. Thus, in this paper, the metrological characterization of this device is also presented, and a direct comparison to a primary Co–C fixed-point cell previously constructed is discussed.     

Mathematical model of Boltzmann’s sigmoidal equation applicable to the set-up of the RF-magnetron co-sputtering in thin films deposition of $$\hbox {Ba}_{{x}}\hbox {Sr}_{1-{x}} \hbox {TiO}_{3}$$

In this work, we present the stoichiometric behaviour of \(\hbox {Ba}^{2+}\) and \(\hbox {Sr}^{2+}\) when they are deposited to make a solid solution of barium strontium titanate. \(\hbox {Ba}_{{x}}\hbox {Sr}_{1-{x}} \hbox {TiO}_{3}\) (BST) thin films of nanometric order on a quartz substrate were obtained by means of in-situ RF-magnetron co-sputtering at 495\({^{\circ }}\)C temperature, applying a total power of 120 W divided into intervals of 15 W that was distributed between two magnetron sputtering cathodes containing targets of \(\hbox {BaTiO}_{3}\) and \(\hbox {SrTiO}_{3}\), as follows: 0–120, 15–105, 30–90, 45–75, 60–60, 75–45, 90–30, 105–15 and 120–0 W. Boltzmann’s sigmoidal modified equation (Boltzmann’s profile) is proposed to explain the behaviour and the deposition ratio Ba/Sr of the BST as a function of the RF-magnetron power. The Boltzmann’s profile proposal shows concordance with experimental data of deposits of BST on substrates of nichrome under the same experimental conditions, showing differences in the ratio Ba/Sr of the BST due to the influence of the substrate.     

New Evaluation of $$T-T_{2000}$$ from 0.02 K to 1 K by Independent Thermodynamic Methods

This paper reports on the results achieved within the European Metrology Research Programme project “Implementing the new kelvin—InK” in the low-temperature range below 1 K. One of the main objectives of the InK project was the determination of new thermodynamic temperature data for comparison with the Provisional Low Temperature Scale 2000 (PLTS-2000), to provide reliable \(T-T_{2000}\) values. To this end, we have investigated three different types of primary thermometers: the current sensing noise thermometer, the primary magnetic field fluctuation thermometer and the Coulomb blockade thermometer. Based on a thorough investigation of the thermometers, detailed uncertainty budgets were established for the measurement of thermodynamic temperatures. Direct comparison measurements between all thermometers demonstrate the agreement of temperature measurements within less than 1 %. Our new \(T-T_{2000}\) data confirm the correctness of the PLTS-2000 in the temperature range from 20 mK up to about 700 mK with relative combined standard uncertainties better than 0.62 %.     

Magnetic measurements,Raman and infrared spectra of metal–ligand complex derived from $$\hbox {CoCl}_{2}\cdot \hbox {6H}_{2}\hbox {O}$$ and 2-benzoyl pyridine

Nanocrystalline complex of \(\hbox {CoCl}_{2}\cdot 6\hbox {H}_{2}\hbox {O}{-}2\)-benzoyl pyridine is prepared by chemical route. Each component of the desired complex is identified by analysing the X-ray diffractograms. Energy-dispersive X-ray analysis (EDX) data confirmed the presence of the desired elements of the sample. Theoretical optimized structure of the complex was derived using ab initio density functional level of theory (DFT) method of calculation. The average nanocrystallite size estimated from the XRD data is \(\sim \)43 nm. Static magnetic property of the complex is studied in the temperature range from 300 K down to 14 K. The estimated magnetic moment of the complex is high when compared to that of the free ion magnetic moment of \(\hbox {Co}^{2+}\) and this is attributed to the less effect of the crystal field acting on the ion in the organic complex due to which orbital moments are not fully quenched. The magnetic property of the complex is also remarkably enhanced compared to that of the diamagnetic 2-benzoyl pyridine which may be suitable for applications in devices. FTIR and Raman spectra of the ligand, 2-benzoyl pyridine and the synthesized complex are recorded at room temperature, which not only confirm the presence of each phase in the complex, but some interesting results are also extracted from the analyses of different Raman active modes of the complex.     

Thermodynamic Properties of ^{4}He Gas in the Temperature Range 4.2–10 K

The thermodynamic properties of $^{4}$ He gas are investigated in the temperature-range 4.2–10 K, with special emphasis on the second virial coefficient in both the classical and quantum regimes. The main input in computing the quantum coefficient is the ‘effective’ phase shifts. These are calculated within the framework of the Galitskii–Migdal–Feynman (GMF) formalism, using the HFDHE2 and Sposito potentials. The virial equation of state is constructed. Extensive calculations are carried out for the pressure–volume–temperature (P–V–T) behavior, as well as chemical potential, and nonideality of the system. The following results are obtained. First, the validity of the GMF formalism for the present system is demonstrated beyond any doubt. Second, the boiling point (phase-transition point) of $^{4}$ He gas is determined from the P–V behavior using the virial equation of state, its value being closest than all previous results to the experimental value. Third, the chemical potential $\upmu $ is evaluated from the quantum second virial coefficient. It is found that $\upmu $ increases (becomes less negative) as the temperature decreases or the number density n increases. Further, $\upmu $ shows no sensitivity to the differences between the potentials used up to n = 10 $^{27}$ m $^{-3}$ . Finally, the compressibility Z is computed and discussed as a measure of the nonideality of the system.     

Spin-Polarized Calculations of Magnetic and Thermodynamic Properties of the Full-Heusler \mathrm{{Co}}_{2}MnZ (Z = Al, Ga)

The purpose of this study is to further understanding of the structural, electronic, magnetic, and thermal properties of the full-Heusler compounds, ${\mathrm{{Co}}}_{2}$ Co 2 MnAl and ${\mathrm{{Co}}}_{2}$ Co 2 MnGa, using density functional theory. Electronic structure calculations will be performed using the full potential linear augmented plane wave. The electronic structures and magnetic properties of ${\mathrm{{Co}}}_{2}$ Co 2 MnZ (Z = Al, Ga) compounds with ${\mathrm{L}}2_{1 }$ L 2 1 structure are studied. It is shown that the calculated lattice constants and spin magnetic moments are in good agreement with experimental values using the general gradient approximation method. Thermal effects on some macroscopic properties of ${\mathrm{{Co}}}_{2}$ Co 2 MnZ (Z = Al, Ga) compounds are predicted using the quasi-harmonic Debye model, in which the lattice vibrations are taken into account. The variations of the lattice constant, volume expansion coefficient, heat capacities, and Debye temperature with pressure and temperature in the ranges of 0 GPa to 18 GPa and 0 K to700 K have been obtained.     

Exploring Solute–Solvent Interactions of \alpha -Amino Acids in Aqueous [\mathrm{EPyBF}_{4}] Arrangements by Volumetric,Viscometric, Refractometric,and Acoustic Approach

Qualitative and quantitative analysis of molecular interaction prevailing in glycine, l-alanine, l-valine, and aqueous solution of ionic liquid (IL) [1-ethylpyridinium tetrafluoroborate ( \(\mathrm{EPyBF}_{4})\) ] have been investigated by thermophysical properties. The apparent molar volume ( \(\phi _{V}\) ), viscosity \(B\) -coefficient, molal refraction ( \(R_{\mathrm{M}}\) ), and adiabatic compressibility ( \(\phi _{ K} )\) of glycine, l-alanine, and l-valine have been studied in 0.001 mol \({\cdot }\, \mathrm{dm}^{-3}\) , 0.003 mol \({\cdot }\, \mathrm{dm}^{-3}\) , and 0.005 mol  \({\cdot } \,\mathrm{dm}^{-3}\) aqueous 1-ethylpyridinium tetrafluoroborate [ \(\mathrm{EPyBF}_{4}\) ] solutions at 298.15 K from the values of densities \((\rho )\) , viscosities ( \(\eta \) ), refractive index ( \(n_{\mathrm{D}})\) , and speed of sound \((u)\) , respectively. The extent of interaction, i.e., the solute–solvent interaction is expressed in terms of the limiting apparent molar volume ( \(\phi _{V}^0 )\) , viscosity \(B\) -coefficient, and limiting apparent molar adiabatic compressibility ( \(\phi _{K}^0)\) . The limiting apparent molar volumes ( \(\phi _{V}^0 )\) , experimental slopes ( \(S_{V}^*)\) derived from the Masson equation, and viscosity \(A\) - and \(B\) -coefficients using the Jones–Dole equation have been interpreted in terms of ion–ion and ion–solvent interactions, respectively. Molal refractions ( \(R_{\mathrm{M}})\) have been calculated with the help of the Lorentz–Lorenz equation. The role of the solvent (aqueous IL solution) and the contribution of solute–solute and solute–solvent interactions to the solution complexes have also been analyzed through the derived properties.     

Wettability of \hbox{R}(01\bar{1}2) single crystalline and polycrystalline \alpha\hbox{-}\hbox{Al}_{2}\hbox{O}_{3} substrates by Al–Si alloys over wide composition and temperature ranges

The wetting behaviors of $\hbox{R}(01\bar{1}2)$ single crystalline and polycrystalline $\alpha\hbox{-}\hbox{Al}_{2}\hbox{O}_{3}$ substrates by Al–Si alloys were studied over wide composition and temperature ranges. The wettability is quite good for all compositions of the alloys. The effect of temperature is moderate while that of the composition is significant. The dependence of the wettability on the alloy composition displays a “valley” profile with the minimum value appearing in the range of 60–70at.%Si. The wetting improvement by the addition of Al to Si mainly results from the decrease in the solid–liquid interfacial free energy by the Al segregation at the interface, while that by the addition of Si to Al results from the decrease in the surface tension of the liquid by the Si segregation.     

Structural and optical properties of diluted magnetic $$\hbox {Ga}_{{1-x}}\hbox {Mn}_{{x}}$$As–AlAs quantum wells grown on high-index GaAs planes

We report on the structural and optical properties of \(\hbox {Ga}_{{1-x}}\hbox {Mn}_{{x}}\hbox {As}\)–AlAs quantum wells (QWs) with \(x = 0.1\%\) grown by molecular beam epitaxy (MBE) on semi-insulating GaAs substrates with orientations (100), (110), (311)B and (411)B. Atomic force microscopy (AFM), X-ray diffraction (XRD) and photoluminescence (PL) techniques were used to investigate these QWs. AFM results have evidenced the formation of Mn-induced islands, which are randomly distributed on the surface. These islands tend to segregate for samples grown on (110) and (411)B planes, while no clear segregation was observed for samples grown on (100) and (311)B orientations. Results show that the PL line width increases with Mn segregation. XRD measurements were used to determine \(2\theta , d\) and cell parameters.