Ion-induced phase transition in the Au–In system

The Au–In equilibrium phase diagram exhibits a large number of intermetallic phases which have recently been explored via perturbed angular correlation spectroscopy, using alloyed and/or diffused ¹¹¹In probes. In the present work we report on the phase transition from Au₇In₃ (hexagonal, γ'-phase) to Au₉In₄ (γ-brass phase) induced via Xe- or Ar-ion implantations at 80 K. We compare the hyperfine parameters with those obtained in thermal equilibrium and after quenching, and argue that ion beam mixing and fast cooling in the condensation phase of thermal (local) spikes are the predominant mechanisms to interpret our findings. This revised version was published online in August 2006 with corrections to the Cover Date.     

Compound formation in Ni/In thin film systems

Interface compound formation in Ni/In film couples has been studied by means of the PAC method using radioactive¹¹¹In probe atoms. Subsequent occurrence of the compounds Ni₁₀In₂₇, Ni₂In₃, NiIn and Ni₃In has been observed after isochronal annealing. Interdiffusion was found to start at temperatures about 250K whereby Ni propagates into the In film.     

真空蒸发法制备放射源

在β谱学的研究中,经常需要薄而均匀的放射源。为此目的,我们设计了一套真空蒸发制源装置,并用它制出了In¹¹⁴,Au¹⁹⁸和Sm¹⁵³的放射源。为了说明问题,我们分别用液滴蒸发和真空蒸发法制备了In¹¹⁴的放射源,用双磁镜和双聚焦β谱仪测量了它们的内转换能谱,并对它们的结果进行了比较。可以看到,真空蒸发法制备源的优点是明显的。此外,也给出了双聚焦β谱仪测量的Sm¹⁵³69.67千电子伏γ射线的K,L_Ⅰ,L_Ⅱ和L_Ⅲ转换电子线以及Au¹⁹⁸411.84千电子伏γ射线的K转换电子线。     

Emission of quasi-thermal ions from a solid bombarded by cluster ions

Comparative studies of the emission of quasi-thermal atomic and cluster ions from V, Nb, Ta, Au, and In targets bombarded by cluster ions Au _m ⁻(m = 1–9), as well as from Si and Bi targets bombarded by cluster ions Au _m ⁻(m = 1–9) and Bi _m ⁻(m = 1–5), with energy E ₀ ranging from 6 to 21 keV are carried out. In the case of bombardment by heavy cluster ions, the fraction of the quasi-thermal component in the energy spectra of sputtered atomic ions reaches 50 (for V, In, and Au), 70 (Nb), or more than 90% (Ta). In addition, quasi-thermal ions play a considerable part in the emission of small cluster ions Au₂⁺, In₂⁺, In₃⁺, and Bi _n ⁺(n = 2–7). The results of the generalizing investigation favor the presence of thermal spike conditions at cluster bombardment and their appreciable contribution to the emission of atomic and small cluster ions.     

Pressure‐induced structural transformations in In2‐xYx(MoO4)3 systems

In this work, we report results of high‐pressure Raman experiments (P < 8 GPa) on In_2‐xY_xMo₃O₁₂ for x = 0.0 and 0.5. A crystalline to crystalline structural phase transition and pressure‐induced amorphization (PIA) have been identified. The structural phase transition takes place at 1.5 and 1.0 GPa for In₂(MoO₄)₃ and In_1.5Y_0.5(MoO₄)₃, respectively, resulting in the change of structure from monoclinic P2₁/a to a more denser structure. The PIA started at 5 and 3.4 GPa for In₂Mo₃O₁₂ and In_1.5Y_0.5Mo₃O₁₂, respectively. The amorphization process takes place in two stages in the case of In_1.5Y_0.5Mo₃O₁₂ phase, while for In₂Mo₃O₁₂, it is not complete until the pressure is as high as 7 GPa. Our results also suggest that with increase of ionic size of the A³⁺ ions, the octahedral distortion increases and consequently larger local structural disorder is introduced in the A₂(MoO₄)₃ system, where A is a trivalent ion (In, Y³⁺, Sc³⁺, Fe³⁺, etc.). Copyright © 2015 John Wiley & Sons, Ltd.     

Co-doping effect of SnO2 and ZnO in In2O3 ceramics: Change in solubility limit and electrical properties

In this study, SnO₂ and ZnO were co-doped in In₂O₃, and the phase development and electrical characteristics were examined. When Zn²⁺ was added to 20 at.% Sn⁴⁺ contained In₂O₃, in which a large amount of In₄Sn₃O₁₂ second phase exists, the amount of the second phase decreased as the content of Zn²⁺ increased, which promoted grain growth and increased carrier mobility. In the case of a simultaneous substitution of Sn⁴⁺ and Zn²⁺ into In₂O₃ with almost the same atomic ratio, a large grain size without second phase was observed, while small grain sizes with many second phases were developed when Sn⁴⁺ and Zn²⁺ were added with different atomic ratios. The electrical characteristics analyzed by Hall effect measurement showed that the electron mobility and conductivity showed a close relationship with the microstructure, while the carrier concentration was almost constant regardless of the Zn²⁺ content.     

High‐temperature thermoelectric properties of Cu2In4Te7

Cu₂Ga₄Te₇ has recently been reported to have a relatively high thermoelectric (TE) figure of merit (ZT). However, the TE properties of Cu₂In₄Te₇, which has the same defect zinc‐blende structure as Cu₂Ga₄Te₇, have been hardly investigated. Here, we demonstrate that Cu₂In₄Te₇ has relatively high ZT values that are similar to those of Cu₂Ga₄Te₇. High‐density polycrystalline bulk samples of Cu₂In₄Te₇ were prepared and their electrical resistivity (?), Seebeck coefficient (S), and thermal conductivity (κ) were measured. Cu₂In₄Te₇ has a maximum ZT of 0.3 at 700 K, with ?, S, and κ values of 62.1 × 10^–5 Ω m, 394 μV K^–1, and 0.61 W m^–1 K^–1, respectively. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Site Occupation of In in RAg6In6 Studied Using PAC Spectroscopy

PAC measurements were performed for ¹¹¹In in LaAg₆In₆, PrAg₆In₆ and NdAg₆In₆. It appears that the probe atom occupy three available sites in the crystal lattice with quite a similar probability. There is a small preference for In atoms to occupy a selected lattice site which is not the same in different compounds.     

Ionic and electronic transport in In2S3 studied via perturbed angular correlation spectroscopy

We report on Perturbed Angular Correlation measurements in polycrystalline In₂S₃ samples in the temperature range from 8 K to 1000 K where two different crystallographic phases β and α occur. As probes, implanted ¹¹¹In nuclei have been used. The three observed EFGs are attributed to probes residing substitutionally in the different sulfur-octahedra and -tetrahedra of β-In₂S₃. A strong damping between 150 K and 300 K has been attributed to EFG fluctuations following the ¹¹¹In(EC)¹¹¹Cd decay. The α-phase (above 680 K) is characterized by a different dynamical damping of the perturbation functions, caused by mobile In atoms. Therefore, the semiconductor In₂S₃ shows, in two different temperature ranges, dynamical PAC-spectra which correspond to different types of mobile charge carriers. Since ¹¹¹In is a self atom in In₂S₃, this compound is an ideal substance to study the charge transport phenomena by the PAC technique. This revised version was published online in August 2006 with corrections to the Cover Date.     

Nuclear magnetic resonance on oriented109In(4.2h) and110In(4.9h) after recoil implantation into Fe

Radioactive¹⁰⁹In(j ^π=9/2⁺;T _1/2=4.2h) and¹¹⁰In(j ^π=7⁺;T _1/2=4.9h) were produced via the¹⁰⁹Ag (α, xn) reactions and recoil-implanted into Fe foils. With the technique of nuclear magnetic resonance on oriented nuclei the magnetic hyperfine splittings were investigated in external magnetic fieldsB ₀=0.5...4.2 kG. The zero-field splitting were measured as 268.9(2)MHz and 147.3(3)MHz for¹⁰⁹InFe and¹¹⁰InFe, respectively. With the known hyperfine fieldB _HF(InFe)=?286.6(5) kG the nuclearg-factors are deduced asg(¹⁰⁹In)=1.231(3) andg(¹¹⁰In)=0.674(2). Our result for¹⁰⁹In shows that theπ g _9/2 g-factors vary by only ～0.1% betweenA=109 and 115. For the |π _9/2 vd _5/2〉₇₊ of¹¹⁰In the additivity relation of magnetic moments is fulfilled to on accuracy of 0.3(3)%.     

The EFG of the In-O-Bond In2O3, AgO and Ag2O

PAC measurements on¹¹¹In in In₂O₃, AgO and Ag₂O were performed to study the influence of different oxygen coordinations to the EFG.¹¹¹In was implanted at 500keV; in addition, AgO and Ag₂O were irradiated in the cyclotron to produce¹¹¹In via the (α, 2n) reaction. Using the point charge model and the known lattice structure of the oxides, the antishielding factor was calculated; it shows a strong dependence on the In-O bondlength.     

Kinetic energy distributions of neutral In and In2 sputtered by polyatomic ion bombardment

Kinetic energy distributions of neutral In monomers and In₂ dimers sputtered from a polycrystalline indium surface under bombardment with 5 keV/atom Au₁⁻ and Au₂⁻ projectiles have been investigated by means of laser postionization time-of-flight mass spectrometry. Results show that 5 keV Au₁ bombardment leads to results in full compliance with linear cascade sputtering theory. For polyatomic ion bombardment, we find a clear transition to a collisional spike dominated emission process. The spike contribution appears as a low-energy part in the sputtered flux which increases with increasing projectile nuclearity and energy. We show that, the velocity spectrum associated with the low-energy contribution is virtually identical for sputtered monomers and dimers. This finding has important implications with respect to the particle emission mechanism under polyatomic projectile bombardment.     

Ferromagnetism in carbon-doped In2O3 thin films

Carbon-doped In₂O₃ thin films exhibiting ferromagnetism at room temperature were prepared on Si (100) substrates by the rf-magnetron co-sputtering technique. The effects of carbon concentration as well as oxygen atmosphere on the ferromagnetic property of the thin films were investigated. The saturated magnetizations of thin films varied from 1.23 to 4.86 emu/cm³ with different carbon concentrations. The ferromagnetic signal was found stronger in samples with higher oxygen vacancy concentrations. In addition, deposition temperature and different types of substrates also affect the ferromagnetic properties of carbon-doped In₂O₃ thin films. This may be related to the oxygen vacancies in the thin film system. The experiment suggests that oxygen vacancies play an important role in introducing ferromagnetism in thin films.     

Photoelectric Phenomena in Au3In5Se9 and Au3Ga5Se9 Compounds

The anisotropy of photoconductivity in Au₃In₅Se₉ and Au₃Ga₅Se₉ crystals grown by the Bridgman method have been investigated as a function of temperature in the temperature range of 100 - 420 K. It is shown that the crystals have a wide range of spectral sensitivity of 0.9 - 1.8 eV. The width of the band gaps and their temperature coefficient are determined. The life time of the current carriers are determined at different levels of excitations.     

The Ag−In intermetallic compound formation from Ag and In electrodeposited layers observed by PAC

The PAC method was applied to study the intermetallic compound formation at Ag−In interfaces. The electrodeposited Ag−In layers of different Ag: In atomic ratios were prepared and isochronal annealing program was performed. For the comparison the bulk Ag₇₅In₂₅ and Ag₆₆In₃₄ specimens were examined. The Ag₂In and AgIn₂ compounds were detected and the quadrupole hyperfine interaction parameters for¹¹¹In in Ag₂In were measured as υ_Q107.9(3) MHz and η=0.48 (2).     

Recombination measurements at low energies with Au49+,50+,51+ at the TSR

Recombination of Au⁴⁹⁺, Au⁵⁰⁺, and Au⁵¹⁺ ions has been studied at the TSR. With Au⁵⁰⁺ ions a storage lifetime of only 2 to 4 s was observed with the magnetically expanded electron beam of the cooler at a density of n_e = 10⁷ cm^-3. This short storage time is a consequence of the highest recombination rate coefficient ever observed with an atomic ion (1.8·10^-6 cm³ s^-1 at zero relative energy E_rel = 0 between electrons and ions). At about 30 meV a huge dielectronic recombination resonance is found with a record small width of only about 15 meV. Such resonances fortuitously occurring near E_rel=0 are probably the main reason for the enhanced recombination rates observed with Au⁵⁰⁺, with Pb⁵³⁺ (in a recent experiment at LEAR) as well as with other complex ions. For Au⁴⁹⁺ and Au⁵¹⁺ the recombination rates are smaller by an order of magnitude. This revised version was published online in August 2006 with corrections to the Cover Date.     

Anisotroper β-Zerfall nach Absorption polarisierter Neutronen an Indium

The anisotropicβ-decay of In¹¹⁶(14 sec)-nuclei, which were polarized by means of polarized neutron absorption, is described. The anisotropy on InF₃, In₂O₃, InP and In-metal at room temperature, 77 °K, 4,2 °K and different magnetic field strengths was measured. Based on the magnitude of the anisotropy and its time dependence it was possible to make predictions concerning nuclear spins, nuclear moments and relaxation phenomena of In¹¹⁶. It was possible to measure by means of this method the nuclear lattice relaxation time of the short-livingβ-active In¹¹⁶(14sec)-nuclei in the different compounds with a great sensitivity.     

Resistance switching properties of In2O3 nanocrystals memory device with organic and inorganic hybrid structure

A memory device with In₂O₃ nanocrystals embedded in a biphenyl-tertracarboxylic dianhydride-phenylen diamine (BPDA-PDA) polyimide layer on a ZnO layer was fabricated, and its electrical properties were evaluated. Then, the transmittance efficiency in the structure of the BPDA-PDA polyimide/In₂O₃ nanocrystals/ZnO/ITO/double polishing sapphire substrate was measured to be about 80% between 440 to 800 nm by ultraviolet-visible transmittance spectroscopy. A bipolar switching current bistability by difference resistance appeared in the sweep voltage rage from −7 to 7 V. It was considered that the bipolar behavior of current-voltage may originate from a resistance fluctuation because of the electron charging effect in In₂O₃ nanocrystals by voltage sweeping, Fowler–Nordheim tunneling, space-charge-limited current, and the migration of O²⁻ ions.     

Structural features of liquid metallic glass former

The structural parameters of Au₇₅Si₂₅ alloy, pure Au, Al₈₈Si₁₂, Cu₈₇Sn₁₃, In₉₈Al₂ and Al₉₃Ni₇ alloys have been measured by X-ray diffractometer. It is found that there are subpeaks in the pair correlation functions in liquid Au₇₅Si₂₅ alloy. The addition of Si in liquid Au results in a decrease in both the correlation radius and the coordination number of the nearest atomic neighbors. The Au₇₅Si₂₅ alloy nearest atomic distance has a more stable dependence on temperature compared to In₉₈Al₂, Al₉₃Ni₇ and Cu₈₇Sn₁₃ alloys. The atomic density change of liquid Au₇₅Si₂₅ alloy is less dependent on temperature than the liquid Au and Al₈₈Si₁₂ alloy. The liquid metallic good glass former Au₇₅Si₂₅ alloy possesses a more stable liquid structure than that of poor glass formers, indicating the essential of the fragility of the superheated melts.     

Synthesis and Growth of New Compounds Au3In5Se9 and Au3Ga5Se9

The phase analysis was performed and a character of interaction in AuInSe₂ - In₂Se₃ and AuGaSe₂ -Ga₂Se₃ quasi-binary systems were considered. The technology of synthesis and growth of single crystals of new semiconducting compounds Au₃In₅Se₉ and Au₃Ga₅Se₉ were developed. The materials for ohmic contacts were chosen and the electrical, optical and thermal properties of obtained compounds have been investigated. The forbidden band gap, its temperature coefficient, the type of the optical transitions and heat capacity of Au₃In₅Se₉ and Au₃Ga₅Se₉ compounds were determined. The charge of entropy and enthalpy has been estimated by numerical integration.