Electrical properties of Bi3.15Nd0.85Ti2.8-xZr0.2MnxO12 thin films with different Mn content synthesized by chemical solution deposition (CSD)

Bi_3.15Nd_0.85Ti_2.8-xZr_0.2Mn_xO₁₂ (BNTZM) thin films with various Mn content (x = 0, 0.005, 0.01, 0.03, and 0.05) have been prepared on Pt/Ti/SiO₂/Si (100) substrates by a chemical solution deposition (CSD) technique. The crystal structures of BNTZM thin film have been analyzed by X-ray diffraction (XRD). The dependence of Mn contents on the ferroelectric, dielectric properties, and leakage current of these BNTZM films have been thoroughly investigated. The XRD analysis demonstrated that all the BNTZM thin films were of typical bismuth-layer-structured ferroelectrics (BLSF) polycrystalline structure and exhibited a highly preferred (117) orientation. Among these BNTZM films, the BNTZM thin film with Mn content equal to 0.01 exhibits the maximum remnant polarization (2P_r) of 48μC/cm² and a low coercive field (2E_c) of 177 kV/cm. In addition, the BNTZM thin film with x = 0.01 (Mn) showed a fatigue-free behavior up to 1 × 10¹⁰ read/write cycles.     

Growth and microstructural features of laser ablated LiCoO2 thin films

Thin films of LiCoO₂ were prepared by pulsed laser deposition technique and the properties were studied in relation to the deposition parameters. The films deposited from a sintered composite target (LiCoO₂+Li₂O) in an oxygen partial pressure of 100 mTorr and at a substrate temperature of 300 °C exhibited preferred c-axis (0 0 3) orientation perpendicular to the substrate surface. The AFM data demonstrated that the films are composed of uniform distribution of fine grains with an average grain size of 80 nm. The grain size increased with an increase in substrate temperature. The (0 0 3) orientation decreased with increase in (1 0 4) orientation for the films deposited at higher substrate temperatures (>500 °C) indicating that the films’ growth is parallel to the substrate surface. The composition of the experimental films was analyzed using X-ray photoelectron spectroscopy (XPS). The binding energy peaks of Co(2p_3/2) and Co(2p_1/2) are, respectively, observed at 779.3 and 794.4 eV, which can be attributed to the Co³⁺ bonding state of LiCoO₂. The electrochemical measurements were carried out on Li//LiCoO₂ cells with a lithium metal foil as anode and LiCoO₂ film as cathode of 1.5 cm² active area using a Teflon home-made cell hardware. The Li//LiCoO₂ cells were tested in the potential range 2.6-4.2 V. Specific capacity as high as 205 mC/cm² μm was measured for the film grown at 700 °C. The growth of LiCoO₂ films were studied in relation to the deposition parameters for their effective utilization as cathode materials in solid-state microbattery application.     

Structure and growth morphology of Gd2O3-doped CeO2 thin films

Gd₂O₃-doped CeO₂ (Gd_0.1Ce_0.9O_1.95, GDC) thin films were synthesized on (1 0 0) Si single crystal substrates by a reactive radio frequency magnetron sputtering technique. Structures and surface morphologies were characterized by X-ray diffraction (XRD), Atomic Force Microscopy (AFM) and one-dimensional power spectral density (1DPSD) analysis. The XRD patterns indicated that, in the temperature range of 200–700 °C, f.c.c. structured GDC thin films were formed with growth orientations varying with temperature—random growth at 200 °C, (2 2 0) textures at 300–600 °C and (1 1 1) texture at 700 °C. GDC film synthesized at 200 °C had the smoothest surface with roughness of R_rms=0.973 nm. Its 1DPSD plot was characterized with a constant part at the low frequencies and a part at the high frequencies that could be fitted by the f^−2.4 power law decay. Such surface feature and scaling behavior were probably caused by the high deposition rate and random growth in the GDC film at this temperature. At higher temperatures (300–700 °C), however, an intermediate frequency slope (−γ₂≈−2) appeared in the 1DPSD plots between the low frequency constant part and the high frequency part fitted by f⁻⁴ power law decay, which indicated a roughing mechanism dominated by crystallographic orientation growth that caused much rougher surfaces in GDC films (R_rms>4 nm).     

YAl3(BO3)4: Crystal growth and characterization

The growth and characterization of YAl₃(BO₃)₄ (YAB), a potential nonlinear optical crystal for the fourth harmonic generation of Nd:YAG laser, was reported. Using top-seeded solution growth method, a YAB crystal with the dimensions of 16×16×18 mm³ was obtained from B₂O₃–Li₂O flux system. The advantages of this flux system and the growth process were discussed in detail. The as-grown YAB crystal was verified by powder X-ray diffraction. The transparency spectra indicated that the cut-off edge of the as-grown YAB was 170 nm. The fourth harmonic generation of a frequency doubled Nd:YAG laser, from 532 to 266 nm, was carried out with a YAB crystal doubler for the first time. Output pulse power obtained was 2.4 mW at 266 nm and the conversion efficiency from 532 to 266 nm was about 15.6%.     

Structural and electrical properties of lead-free perovskite ceramic: Ba(In1/2Nb1/2)O3

Lead-free perovskite Ba(In_1/2Nb_1/2)O₃ was prepared by conventional ceramic fabrication technique at 1350 °C/5 h in air atmosphere. The crystal symmetry, space group and unit cell dimensions were determined from Rietveld analysis using FullProf software whereas crystallite size and lattice strain were estimated from Williamson-Hall approach. XRD analysis of the compound indicated the formation of a single-phase cubic structure with the space group Pm3m. EDAX and SEM studies were carried out in order to evaluate the quality and purity of the compound. Complex impedance as well as electric modulus analyses suggested the dielectric relaxation to be of non-Debye type. The correlated barrier hopping (CBH) model was employed to successfully explain the mechanism of charge transport in Ba(In_1/2Nb_1/2)O₃.     

Effects of Nb2O5 Replacement by Er2O3 on elastic and structural properties of 75TeO2-(10 − x)Nb2O5-15ZnO-(x)Er2O3 glass

Tellurite 75TeO₂-(10 − x)Nb₂O₅-15ZnO-(x)Er₂O₃; (x = 0.0-2.5 mol%) glass system with concurrent reduction of Nb₂O₅ and Er₂O₃ addition have been prepared by melt-quenching method. Elastic properties together with structural properties of the glasses were investigated by measuring both longitudinal and shear velocities using the pulse-echo-overlap technique at 5 MHz and Fourier Transform Infrared (FTIR) spectroscopy, respectively. Shear velocity, shear modulus, Young's modulus and Debye temperature were observed to initially decrease at x = 0.5 mol% but remained constant between x = 1.0 mol% to x = 2.0 mol%, before increasing back with Er₂O₃ addition at x = 2.5 mol%. The initial drop in shear velocity and related elastic moduli observed at x = 0.5 mol% were suggested to be due to weakening of glass network rigidity as a result of increase in non-bridging oxygen (NBO) ions as a consequence of Nb₂O₅ reduction. The near constant values of shear velocity, elastic moduli, Debye temperature, hardness and Poisson's ratio between x = 0.5 mol% to x = 2.0 mol% were suggested to be due to competition between bridging oxygen (BO) and NBO ions in the glass network as Er₂O₃ gradually compensated for Nb₂O₅. Further addition of Er₂O₃ (x > 2.0 mol%) seems to further reduce NBO leading to improved rigidity of the glass network causing a large increase of ultrasonic velocity (v_L and v_S) and related elastic moduli at x = 2.5 mol%. FTIR analysis on NbO₆ octahedral, TeO₄ trigonal bipyramid (tbp) and TeO₃ trigonal pyramid (tp) absorption peaks confirmed the initial formation of NBO ions at x = 0.5 mol% followed by NBO/BO competition at x = 0.5-2.0 mol%. Appearance of ZnO₄ tetrahedra and increase in intensity of TeO₄ tbp absorption peaks at x = 2.0 mol% and x = 2.5 mol% indicate increase in formation of BO.     

Distorted icosahedral Ni5Nb3Zr5 clusters in the as-quenched and hydrogenated amorphous (Ni0.6Nb0.4)0.65Zr0.35 alloys

Local structures of the hydrogenated (Ni_0.6Nb_0.4)_1-xZr_x (x = 0.3-0.4) amorphous alloys attract much attention for the sake of their epoch-making electronic transport behaviors. We investigated the local structures by XAFS for the as-quenched (Ni_0.6Nb_0.4)_0.65Zr_0.35 and hydrogenated [(Ni_0.6Nb_0.4)_0.65Zr_0.35]_0.922H_0.078 amorphous alloys, in which ballistic conductivity has been observed. XAFS results of the Ni K-edge are analyzed based on the structure model deduced by the first principle calculation. The analysis suggests that highly distorted icosahedral Ni₅Nb₃Zr₅ cluster, which has a centered-Ni and a surrounding Nb triangle, is a main structural unit of (Ni_0.6Nb_0.4)_0.65Zr_0.35 and the [(Ni_0.6Nb_0.4)_0.65Zr_0.35]_0.922H_0.078 amorphous alloys. This distorted icosahedral Ni₅Nb₃Zr₅ cluster can be associated with the occurrence of the singular electronic transport behaviors of the hydrogenated (Ni_0.6Nb_0.4)_0.65Zr_0.35 alloy.     

Electrical and corrosion properties of the Ti5Si3 thin films coated on glass substrate by APCVD method

Ti₅Si₃ thin films were coated on glass substrate by atmospheric pressure chemical vapor deposition method at different temperatures. Electrical and corrosion properties of the thin films were investigated. The results show that the electrical resistivity of the thin films decreases initially with the increase in deposition temperature. However, it increases with the further increase of the temperature. The lowest electrical resistivity of 107 μΩ⋅cm is obtained at 710 °C. The least corrosion rates of the thin films at 95 °C of 0.10 nm/min and 0.13 nm/min in 1 N and 10 N acid solution and of 0.33 nm/min and 6.55 nm/min in 1 N and 10 N alkali solution, respectively, are obtained by weight-loss measurement method. The corrosion mechanisms of the thin films were also discussed in detail.     

Potentiodynamic polarization studies on amorphous Zr46.75Ti8.25Cu7.5Ni10Be27.5, Zr65Cu17.5Ni10Al7.5, Zr67Ni33 and Ti60Ni40 in aqueous HNO3 solutions

Potentiodynamic polarization studies were carried out on virgin specimens of Zr-based bulk amorphous alloys Zr_46.75Ti_8.25Cu_7.5Ni₁₀Be_27.5 and Zr₆₅Cu_17.5Ni₁₀Al_7.5, and conventional-type binary amorphous alloys Zr₆₇Ni₃₃ and Ti₆₀Ni₄₀ in solutions of 0.2 M, 0.5 M and 1.0 M HNO₃ at room temperature. The values of the corrosion current density (I_corr) for the bulk amorphous alloy Zr_46.75Ti_8.25Cu_7.5Ni₁₀Be_27.5 were found to be comparable with those of Zr₆₅Cu_17.5Ni₁₀Al_7.5 in 0.2 M and 0.5 M HNO₃, but the value of I_corr for the former was almost three times more than that of the latter in 1.0 M HNO₃. In the case of conventional binary amorphous alloys, Ti₆₀Ni₄₀ showed lower value of I_corr as compared to Zr₆₇Ni₃₃ in 0.5 M and 1.0 M HNO₃ and a comparable value of I_corr in 0.2 M HNO₃. In general, the binary Ti₆₀Ni₄₀ displayed the best corrosion resistance among all the alloys in all the cases and the corrosion current density (I_corr) for all the alloys was found to increase with the increasing concentration of nitric acid. It is noticed that the bulk amorphous alloys do not possess superior corrosion resistance as compared to conventional binary amorphous alloys in aqueous HNO₃ solutions. The observed differences in their corrosion behavior are attributed to different alloy constituents and composition of the alloys investigated.     

Growth of epitaxial TmFeCuO4 thin films by pulsed laser deposition

Epitaxial thin films of TmFeCuO₄ with a two-dimensional triangular lattice structure were successfully grown on yttria-stabilized-zirconia substrates by pulsed laser deposition and ex situ annealing in air. The films as-deposited below 500 °C showed no TmFeCuO₄ phase and the subsequent annealing resulted in the decomposition of film components. On the other hand, as-grown films deposited at 800 °C showed an amorphous nature. Thermal annealing converted the amorphous films into highly (0 0 1)-oriented epitaxial films. The results of scanning electron microscopic analysis suggest that the crystal growth process during thermal annealing is dominated by the regrowth of non-uniformly shaped islands to the distinct uniform islands of hexagonal base.     

Structural,electrical and optical properties of SnO2 films deposited on Y-stabilized ZrO2 (1 0 0) substrates by MOCVD

SnO₂ films have been deposited on Y-stabilized ZrO₂ (YSZ) (1 0 0) substrates at different substrate temperatures (500–800 °C) by metalorganic chemical vapor deposition (MOCVD). Structural, electrical and optical properties of the films have been investigated. The films deposited at 500 and 600 °C are epitaxial SnO₂ films with orthorhombic columbite structure, and the HRTEM analysis shows a clear epitaxial relationship of columbite SnO₂(1 0 0)||YSZ(1 0 0). The films deposited at 700 and 800 °C have mixed-phase structures of rutile and columbite SnO₂. The carrier concentration of the films is in the range from 1.15×10¹⁹ to 2.68×10¹⁹ cm⁻³, and the resistivity is from 2.48×10⁻² to 1.16×10⁻² Ω cm. The absolute average transmittance of the films in the visible range exceeds 90%. The band gap of the obtained SnO₂ films is about 3.75–3.87 eV.     

Crystal growth and luminescent properties of Pr-doped K(Y,Lu)3F10 single crystal for scintillator application

Pr1%:K(Y_1−xLu_x)₃F₁₀ (x=0, 0.2, 0.4) single crystals were grown by the μ-PD method. All the grown crystals were greenish and perfectly transparent without any inclusions or cracks. Radioluminescence spectra and decay kinetics of the Pr1%:K(Y,Lu)₃F₁₀ crystals were measured. Emission from the Pr³⁺ 5d–4f transition, peaking around 260 nm and of the decay time of around 22 ns were observed. The 5d–4f emission intensities of the Pr1%:K(Y,Lu)₃F₁₀ crystals were higher than that of the standard BGO scintillator.     

Growth and Raman spectroscopic characterization of As4S4 (II) single crystals

As described by Kutoglu (1976 [16]), single crystals of As₄S₄ (II) phase have been grown using a new two-step synthesis that drastically increases the reproducibility that is attainable in synthetic experiments. First, through photo-induced phase transformation, pararealgar powder is prepared as a precursor instead of AsS melt. Then it is dissolved and recrystallized from CS₂ solvent. Results show that single crystals of the As₄S₄ (II) phase were obtained reproducibly through the dissolution–recrystallization process. Single crystals of As₄S₄ (II) obtained using this method were translucent and showed a uniform yellow-orange color. The crystal exhibits a platelet-like shape as a thin film with well-developed faces (0 1 0) and (0 1¯ 0). The grown crystals are as large as 0.50×0.50×0.01 mm. They were characterized using powder and single crystal X-ray diffraction techniques to confirm the phase identification and the lattice parameters. The As₄S₄ (II) phase crystallizes in monoclinic system with cell parameters a=11.202(4) Å, b=9.954(4) Å, c=7.142(4) Å, β=92.81(4)°, V=795.4(6) Å³, which shows good agreement with the former value. Raman spectroscopic studies elucidated the behavior of the substance and the relation among phases of tetra-arsenic tetrasulfide.     

Influence of outphase Cu50Ti50 amorphous alloy addition on microstructural evolution of mechanically alloyed Zr66.7Ni33.3 amorphous alloy

The influence of outphase Cu₅₀Ti₅₀ amorphous alloy addition on microstructural evolution of Zr_66.7Ni_33.3 amorphous alloy has been investigated using a mechanical alloying method. It has been found that the milling induced microstructural evolution is related to the change of peak positions of the first maximum on X-ray diffraction patterns of the as-obtained amorphous alloys. With increasing milling time, the 3 wt.% Cu₅₀Ti₅₀ addition can give rise to the cyclic amorphization transformation of the as-milled alloy. The mechanical stability of the mixing amorphous phase can be greatly enhanced with increasing Cu₅₀Ti₅₀ addition up to 10 wt.%. Moreover, the addition of outphase Cu₅₀Ti₅₀ amorphous alloy not only increases the onset crystallization temperature of Zr_66.7Ni_33.3 amorphous alloy but also alters its crystallization mode. The effect of outphase amorphous addition on the mechanical stability of the Zr_66.7Ni_33.3 amorphous phase has been discussed based upon the bond order theory.     

Crystal growth of KInO2 from a hydroxide flux

Single crystals of KInO₂ were obtained from a reactive potassium hydroxide flux at 700 °C. KInO₂ crystallizes in the R-3m crystal system with a=3.2998(10) Å, c=18.322(10) Å and V=172.78(12) Å³. The crystal structure is isotypic with that of α-NaFeO₂ and consists of the (1 1 1) layers being occupied alternately by KO₆ and InO₆ octahedra. Three different AInO₂ structure types are discussed.     

Growth and property of Zn-doped near-stoichiometric LiTaO3 crystal

Near-stoichiometric LiTaO₃ (SLT) and Zn-doped near-stoichiometric LiTaO₃ (Zn:SLT) crystals with 10–15 mm in diameter and 10 mm in length were grown by using TSSG technique with K₂O as the flux. The effect of adding amount of K₂O was discussed in the growing process. The crystals were characterized by inductively coupled plasma-optical emission (ICP-OES), X-ray diffraction (XRD) and differential thermal analysis (DTA). The lattice constants of Zn:SLT were smaller than those of SLT and Curie temperature was higher than that of SLT. It was found that Zn doping is an efficient way to improve the optical damage resistance ability of SLT crystal. Compared with SLT crystal, Zn:SLT exhibited a much higher optical damage threshold, more than 500 MW/cm², which was attributed to Zn self-compensated effect that formed the charge compensated complexes, (Zn_Ta)³⁻–3(Zn_Li)⁺ in SLT crystal.     

Lu5Ir4Si10 whiskers: Morphology,crystal structure,superconducting and charge density wave transition studies

Highly perfect single crystal whiskers of Lu₅Ir₄Si₁₀ were successfully grown out of the melt. Details of the surface and morphology of the whiskers are presented. X-ray diffraction data confirmed that the whisker structure has the same tetragonal P4/mbm space group symmetry as bulk single crystals with lattice parameters a=12.484(1) and c=4.190(2) Å. By means of field emission scanning electron microscopy, the morphology of the whiskers has been studied. Using a 4-circle X-ray diffractometer we found that whiskers grow along the c-axis direction and all side faces are oriented along the [1 1 0] direction. The mosaicity has been measured and is found to be almost perfect: below 0.15° along the c-axis. According to our transport measurements performed along the c-axis, the whiskers present a sharp superconducting transition at T_c=4.1 K and show a charge density wave (CDW) transition at 77 K. From the hysteresis of the temperature dependance of the electrical resistivity study, the CDW transition is found to be of first order.     

Crystallization kinetics in Cu46Zr45Al7Y2 bulk metallic glass by differential scanning calorimetry (DSC)

Crystallization transformation kinetics in isothermal and non-isothermal (continuous heating) modes were investigated in Cu₄₆Zr₄₅Al₇Y₂ bulk metallic glass by differential scanning calorimetry (DSC). In isochronal heating process, activation energy for crystallization at different crystallized volume fraction is analyzed by Kissinger method. Average value for crystallization in Cu₄₆Zr₄₅Al₇Y₂ bulk metallic glass is 361 kJ/mol in isochronal process. Isothermal transformation kinetics was described by the Johnson-Mehl-Avrami (JMA) model. Avrami exponent n ranges from 2.4 to 2.8. The average value, around 2.5, indicates that crystallization mechanism is mainly three-dimensional diffusion-controlled. Activation energy is 484 kJ/mol in isothermal transformation for Cu₄₆Zr₄₅Al₇Y₂ bulk metallic glass. These different results were discussed using kinetic models. In addition, average activation energy of Cu₄₆Zr₄₅Al₇Y₂ bulk metallic glass calculated using Arrhenius equation is larger than the value calculated by the Kissinger method in non-isothermal conditions. The reason lies in the nucleation determinant in the non-isothermal mode, since crystallization begins at low temperature. Moreover, both nucleation and growth are involved with the same significance during isothermal crystallization. Therefore, the energy barrier in isothermal annealing mode is higher than that of isochronal conditions.     

Fabrication and characteristics of CeO2 films on Si(1 0 0) substrates by pulsed laser deposition

A detailed investigation about the dependence of film orientation on deposition temperature and ambient oxygen pressure has been carried out for CeO₂ films on Si(1 0 0) substrates using pulsed laser deposition. It has been found that the CeO₂ film orientation varies with increasing oxygen pressure at 750°C deposition temperature. In addition, the recovery of preferential orientation of CeO₂ films grown at 20 Pa ambient oxygen pressure with increasing deposition temperature has also been found for the first time. X-ray photoelectron spectroscopy (XPS) measurements confirm that stoichiometric CeO₂ films can be grown at lower oxygen pressure (5×10⁻³ Pa). HRTEM result also indicates that the CeO₂ films grown at low oxygen pressure are of high crystallinity.