Indium-tin Alloy Research Articles

The equilibrium surface composition of some indium-lead and indium-tin alloys

Auger electron spectra have been obtained from the near surface region of six equilibrated, solid, single-phase alloys — four in the In-Pb system and two in the In-Sn system — at temperatures ranging from 20°C to near the melting point of each. For dilute solutions, the surface is enriched in the solute, the amount increasing with decreasing temperature. As the bulk solute concentration is increased, the relative enrichment in the surface decreases, and at a sufficiently high solute concentration the surface becomes depleted in the solute. These results are consistent with an earlier study of the tin-lead alloy system and with the thermodynamics of non-ideal solutions. Together with the results from the tin-lead system, they represent the first systematic study of the equilibrium surface composition of a series of non-ideal solutions covering several alloy systems.

Data acquisition and processing modes for quantitative Auger electron spectroscopy

Auger electron spectroscopy has been applied to the quantitative surface analysis of a series of metals (Ag, Cd, In, Sn), indium-tin alloys, indium and tin oxides, and indium-tin oxide (ITO) films. Spectra were obtained by two methods: the conventional modulation technique, which results in the derivative spectrum, and a direct current measurement, which gives an undifferentiated spectrum. For data collected in the latter mode, an instrumental approach and secondary electron background correction are discussed. Quantitative results obtained by using this approach are shown to be more accurate than the traditional measurement method. 7 figures, 3 tables.

Effect of ion sputtering on the surface composition of indium-lead and indium-tin alloys

Abstract The effect of argon ion sputtering on the surface composition of a series of InPb and InSn single phase alloys (In 0.998 Pb 0.002 , In 0.5 Pb 0.5 , In 0.1 Pb 0.9 , In 0.9 Sn 0.1 , and In 0.02 Sn 0.98 ) has been examined by Auger electron spectroscopy. The results are consistent with the hypothesis that the alloy component with the higher binding energy, i.e., the higher heat of atomization, becomes enriched in the near surface region.

Effect of ion sputtering on the surface composition of indium-lead and indium-tin alloys

The effect of argon ion sputtering on the surface composition of a series of InPb and InSn single phase alloys (In 0.998Pb 0.002, In 0.5Pb 0.5, In 0.1Pb 0.9, In 0.9Sn 0.1, and In 0.02Sn 0.98) has been examined by Auger electron spectroscopy. The results are consistent with the hypothesis that the alloy component with the higher binding energy, i.e., the higher heat of atomization, becomes enriched in the near surface region.

In-Sn合金のマルテンサイト変態の結晶学的研究

The fct(β,c⁄a<1)\ ightleftarrowsfct(α′,c⁄a>1) phase transformation in indium-rich tin solid solutions has been studied by means of X-ray and electron diffraction, with supplement of metallographic observations. The β\ ightleftarrowsα′ phase transformation is of the diffusionless (martensitic) kind, and takes place with a mechanism involving cooperative atomic movements. The atomic movements of the phase transformation can be explained by considering a coupling of two predominant TA1 phonon modes with low frequencies, as in the cases of the In-Tl, In-Cd and In-Pb alloys. After the reverse transformation (α′→β) upon heating, the orientations of the reverted β phase crystal do not always agree with the original ones of the initial β phase (matrix) crystal, i.e. the β\ ightleftarrowsα′ phase transformation is not always crystallographically reversible. It was also found that the indium-tin alloys are slightly decomposed during heating for the reverse transformation; the decomposition process depends strongly on the grain size. The behavior of forward and reverse transformations is quite similar to that of the burst type in Fe-Ni alloys, although for the latter a decomposition process does not interfere with the transformation. It is concluded that the partial shape recovery is mainly associated with an imperfect crystallographical reversibility and also that a gradual decrease in shape memory effect, which was observed after keeping at room temperature for a long period of time, is related with the intermediate stage of α′→(α+β) decomposition. The imperfect crystallographical reversibility may result from the large atomic displacements of the phase transformation.

Enhancement of electron-phonon interaction at the lifshits transitions in indium

Anomalous dependences of 2Δ 0 T c on pressure and impurity concentrations were studied experimentally in indium and indium-tin alloys in the vicinity of the Lifshits transitions. The possible reasons for this phenomenon are discussed.

Some properties of indium-tin oxide films

Thin films of indium-tin oxide have been deposited by DC diode sputtering from an indium-tin alloy target in an argon, hydrogen and oxygen atmosphere. Films with sheet resistance of 11 ohms/square and 80% light transmission have been obtained. The effect of cathode composition and gas mixture on sheet resistance and optical transmission properties of the films have been studied.

Single-particle electron-tunneling investigation of the phonon spectra and superconductivity of indium-tin alloys

Single-particle electron tunneling through an oxide barrier, between two metal films, Al--oxide--In/sub x/Sn/sub 1-x/, has been investigated in a study of the lattice and superconducting properties, in particular the phonon density of states, of the four distinct single-phase alloys of the In-Sn system. Measurements of the dynamic resistance of the junction, and second-harmonic response to first-harmonic stimulation across the junction, with the metal films in their superconducting state, have been analyzed using the Eliashberg gap equations and the McMillan computer program. The product function ..cap alpha../sup 2/(..omega../sub q/) F (..omega../sub q/), which exhibits the structure of the density of phonon states, F (..omega../sub q/), has been determined for nine intermediate In-Sn compositions. Here F (..omega../sub q/) is the phonon density of states, and ..cap alpha../sup 2/(..omega../sub q/) is an electron-phonon coupling parameter which varies slowly with ..omega../sub q/. In the determination of the phonon spectra, the following normal-state properties of In and Sn, and their alloys have been computed: the Coulomb pseudopotential ..mu..*; the electron-phonon interaction strength lambda; and an average phonon energy . These three normal-state parameters were used to calculate the superconducting transition temperatures using the McMillan T/sub c/ equation. These calculated transition temperatures aremore » compared with our directly measured T/sub c/'s and with previously measured values. (AIP)« less

Microwave studies of superconducting two-phase IN-SN

The variation of surface resistance with temperature and composition was determined for the indium-tin alloy system. Measurements made at 3 GHz enabled small inclusions of phases to be detected. Typically two transitions were seen corresponding to the eutectic and proeutectic constituents of the alloys. Between these transitions the surface resistance hardly changed with temperature. The flatness and mean value of the surface resistance in this temperature range were found to vary with the alloy’s composition and the annealing conditions. Annealing was also found to affect the width of the superconducting transitions. Explanations for the results are suggested in terms of the flow of current in such systems and the proximity effect. Evidence was seen of a third transition under some annealing conditions. This extra transition may be explained by altering the beta phase boundary or adding a new intermediate phase to the present phase diagram. It is also suggested that the γ -phase should begin at about 72 at. % tin rather than that presently accepted.

Third-Order Elastic Constants of Tin and of a Tin-Indium Alloy

Third-Order Elastic Constants of Tin and of a Tin-Indium Alloy

Anomalies in the enthalpy of mixing in alpha-phase indium-tin due to brillouin zone effects

Enthalpies of crystallization have been measured for indium-tin alloys containing 7–9 at.% tin using differential thermal analysis (DTA). From the values obtained the enthalpies of mixing, ΔH m' in the solid state were calculated. In the ΔH m vs. composition curve there is a change in slope at 7.80 at.% tin, a maximum at 8.10% and a sharp minimum at 8.31%. This behaviour is qualitatively explained by varying electronic and lattice energies in connection with Fermi surface-Brillouin zone interaction. New pieces of Fermi surface in the third zone are assumed to appear at 8.10 at.% tin. The height of the dip is about 1.2 meV atom .

Fluctuation effects in the resistive transition of thin filamentary superconductors

A progress report on new and improved measurements of the resistive transitions in tin and tin-indium alloy whisker crystals shows results that can be fitted reasonably well from the onset at low temperature through the excess conductivity tail above the critical temperature by application of existing theories of intrinsic fluctuations. The breadth of the transitions seems to be quantitatively accounted for. The theory of Langer and Ambegaokar as modified by McCumber and Halperin is applicable at the lowest voltage portion of the onset of the transitions at least in pure tin crystals, and the Aslamazov-Larkin theory is applicable at the high temperature tail in alloy crystals. The current dependence of the voltage at T c and the entire transition shape for alloy whiskers fits a scheme of Masker et al. based on the time-dependent Ginsburg-Landau equations.

Calorimetric Determination of the Density of Electronic States inα-Phase Indium Alloys. I. Alloys with Tin

The low-temperature heat capacity of each of a series of indium-tin alloys containing 0-13 at.% tin has been measured, and the density of electronic states $N({E}_{F})$ and the Debye temperature ${\ensuremath{\Theta}}_{0}$ evaluated. The electron-phonon coupling constant $\ensuremath{\lambda}$ was calculated from the super-conducting critical temperature ${T}_{c}$ and ${\ensuremath{\Theta}}_{0}$, and was used to derive the band-structure density of states ${N}_{\mathrm{bs}}({E}_{F})$. Both ${N}_{\mathrm{bs}}({E}_{F})$ and $\ensuremath{\lambda}$ increase more rapidly with increasing tin content above 9 at.% tin than below 9 at.%. These results are interpreted in terms of the Brillouin-zone-boundary-Fermi-surface interaction that has been postulated to explain the behavior of the lattice parameters and ${T}_{c}$. Comparison with band-structure calculations and experimental Fermi-surface studies for pure indium suggest that new parts of the Fermi surface appear in the third zone at this electron concentration.

Free energy of mixing and activity of indium-tin alloy

Flory's model has been used to calculate the free energy of mixing and activity of In in InSn liquid alloy at 700 K. The values of these thermodynamic parameters obtained from this model are compared with corresponding experimental values. The computed values are in reasonable agreement with the observed values. Keywords: Flory's model; Activity; Indium-tin alloy DOI: 10.3126/bibechana.v7i0.4040BIBECHANA 7 (2011) 26-29

Tunneling into Superconducting Films in a Magnetic Field

Tunneling experiments were performed on thin superconducting films in the presence of a magnetic field. The experiments were done at ${\mathrm{He}}^{3}$ temperatures on tin and tin-indium alloy films with thicknesses between 600 and 2000 \AA{}. As expected theoretically, the effect of the field on the density of states is, for dirty films, similar to the effect of paramagnetic impurities with the square of the magnetic field playing a role analogous to the paramagnetic impurity concentration. The data are compared with the theoretical results of Maki for the limit of zero mean free path, and agreement is fair. The difference between these results and those of this experiment is attributed to the finite mean free path. Str\"assler and Wyder have calculated the field dependence of the density of states for small particles with arbitrary mean free path. We find that their calculations are in good agreement with experiment.

Microwave surface resistance of type II superconductors

An experiment has been performed to investigate the mixed state of type II superconductors by simultaneously measuring the real part of the surface impedance at 1·2 Gc/s and the magnetization. The surface resistance could thus be related to the magnetic condition of the specimen both during the initial magnetization and afterwards. The specimens were in the form of 1·6 mm diameter wires wound into helices and the steady field was applied parallel to the axis of the helix. In the first place tin-indium alloys having 0 to 7 at. % of indium were used, and most of the data were obtained with this alloy system. Lead alloys were used later. The results differ from those of Rosenblum et al ., who worked at 23 Gc/s, in that the surface resistance was found to be sensitive to the surface condition of the specimen. But consistent results were obtained when the specimens had been chemically or electrolytically polished and a comparison is made between the data at the two frequencies. Expressed as a fraction of its value in the normal state the surface resistance at 1·2 Gc/s is found to obey the same universal function of field and temperature as at the higher frequency when allowance is made for the difference in geometrical arrangement. It is argued that the pinning mechanisms which prevent flux lines moving in response to a small direct current are unlikely to be effective in preventing high frequency oscillations. Microwave power will therefore be absorbed in the specimen owing to the damping of flux line motion by the same viscous force which is held to account for the d. c. resistivity when the current is large enough to overcome the pinning. The microwave surface resistance should therefore be closely related to the d. c. resistivity of an ideal type II superconductor with no pinning centres. In this way most of the features of the microwave data are explained qualitatively but a surface resistance is predicted which in fields much weaker than the upper critical field is larger than the experimental value.

Magnetic properties of thin films of soft superconductors

The torque method of measuring the magnetic properties of thin superconducting layers is discussed, and some results reported for experiments in which magnetic fields are applied parallel and perpendicular to the plane of evaporated films of tin, indium and indium-tin alloy. For the parallel case critical fields and supercooling fields can be measured. For the perpendicular case magnetization curves can be derived from the torque curves. The magnetization curves have been studied in some detail and comparison made with the properties of bulk type 2 superconductors.

The effect of high pressure on the lattice parameters of indium and its alloys

The effect of pressure to several hundred kbars has been measured on the lattice parameters of indium of an indium-tin alloy, and of two indium-thallium alloys. All four systems crystallize in the face centered tetragonal structure. All showed a maximum in c a in the region V V 0 = 0·88–0·84 . Pure indium and the thallium alloys behaved very much alike, while the tin alloy has a considerably lower maximum for c/a/( c/a) 0 at a lower V V 0 .

Superconducting and Normal State Properties of Dilute Indium-Tin Alloys: Bulk and Thin Film

Superconducting and Normal State Properties of Dilute Indium-Tin Alloys: Bulk and Thin Film

Untersuchungen an Zinn und Indium-Zinn-Legierungen im supraleitenden Zustand mit Hilfe des M�ssbauer-Effekts

The recoilless nuclear resonance absorption of the 23.8 keV-γ-line of119Sn was measured in a transmission experiment. The measurements were performed with tin and tin-indium alloys, as a function of temperature above and below the transition points of superconductivity (2 ‡K<T<6 ‡K). The Lamb-Moessbauer-factors, the Debye-temperatures, and an upper limit of the quadrupol interaction were calculated from the data. Within the experimental accuracy there is no evidence for a difference of the quantities mentioned above in the normal and super-conducting state down toT=0.6T c . The data for the isomeric shift yield a constants-electron density within the nucleus in the two states within 2·10−4 down toT=0.8T c .