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Ripple patterns created by sputter erosion of iron thin films induce a correlated magnetic texture of the surface near region. We investigated the magnetic anisotropy as a function of the residual film thickness and determined the thickness of the magnetically anisotropic layer as well as the magnitude of the magnetic anisotropy using by magneto-optical Kerr effect (MOKE) and Rutherford backscattering spectroscopy measurements. Ripple patterns were created by sputter erosion with 5 keV Xe ions under grazing incidence of 80° with respect to the surface normal. For ion fluences of above 1×1016 cm-2, the formation of ripples, with wavelengths between 30 and 80 nm oriented parallel to the ion beam direction, is observed. MOKE measurements reveal a pronounced uniaxial magnetic anisotropy of the surface region of the films with orientation parallel to the ripple orientation and the ion beam direction. We find a layer thickness of 12±3 nm, in accordance with the average grain size. The magnetic anisotropy within this layer varies from about 25% for thick residual films toward 100% for films with less than 30 nm thickness. The magnitude of the magnetic anisotropy is determined by the shape anisotropy of the rippled surface as well as the interface roughness. We have demonstrated that sputter erosion yields highly anisotropic magnetic thin films and can be used to fabricate nanorods and nanowires with pronounced uniaxial magnetic anisotropy. [ABSTRACT FROM AUTHOR]

Reflection-absorption infrared spectroscopy has been employed to observe Si-H bonds within a model, ultrathin silicon oxide. Upon heating a monolayer of H[sub 8]Si[sub 8]O[sub 12]/Si(100 - 2 × 1 to 700 °C, Si-H bonds as a part of HSiO[sub 3] entities are still detected within the oxide layer after cooling. These fragments appear to be stable to temperatures of at least 850 °C. Reversible hydrogen/deuterium exchange for these entities is also directly observed. [ABSTRACT FROM AUTHOR]

Considers the effects of growth parameters and substrate type on the characteristics of the metalorganic chemical vapor deposition-grown barium titanate thin films. Method used to study the surface and the cross-sectional morphology of the films; Surface morphology and microstructure of the thin films; Substrate effect on the thin film growth.

NbN x layers were deposited by reactive magnetron sputtering on MgO(001) substrates in 0.67 Pa pure N 2 at T s = 600–1000 °C. T s ≥ 800 °C leads to epitaxial layers with a cube-on-cube relationship to the substrate: (001) NbN ||(001) MgO and [100] NbN ||[100] MgO . The layers are nearly stoichiometric with x = 0.95–0.98 for T s ≤ 800 °C, but become nitrogen deficient with x = 0.81 and 0.91 for T s = 900 and 1000 °C. X-ray diffraction reciprocal space maps indicate a small in-plane compressive strain of − 0.0008 ± 0.0004 for epitaxial layers, and a relaxed lattice constant that decreases from 4.372 Å for x = 0.81 to 4.363 Å for x = 0.98. This unexpected trend is attributed to increasing Nb and decreasing N vacancy concentrations, as quantified by first-principles calculations of the lattice parameter vs. point defect concentration, and consistent with the relatively small calculated formation energies for N and Nb vacancies of 1.00 and − 0.67 eV at 0 K and − 0.53 and 0.86 eV at 1073 K, respectively. The N-deficient NbN 0.81 (001) layer exhibits the highest crystalline quality with in-plane and out-of-plane x-ray coherence lengths of 4.5 and 13.8 nm, attributed to a high Nb-adatom diffusion on an N-deficient growth front. However, it also contains inclusions of hexagonal NbN grains which lead to a relatively high measured hardness H = 28.0 ± 5.1 GPa and elastic modulus E = 406 ± 70 GPa. In contrast, the nearly stoichiometric phase-pure epitaxial cubic NbN 0.98 (001) layer has a H = 17.8 ± 0.7 GPa and E = 315 ± 13 GPa. The latter value is slightly smaller than 335 and 361 GPa, the isotropic elastic modulus and the [100]-indentation modulus, respectively, predicted for NbN from the calculated c 11 = 641 GPa, c 12 = 140 GPa, and c 44 = 78 GPa. The electrical resistivity ranges from 171 to 437 μΩ cm at room temperature and 155–646 μΩ cm at 77 K, suggesting carrier localization due to disorder from vacancies and crystalline defects. [ABSTRACT FROM AUTHOR]

Polycrystalline vanadium thin films of 50, 75, and 100 nm thickness were deposited by magnetron sputtering of a vanadium metal target of 2 inch diameter with 99.9% purity on native oxide covered Si substrates. One set of the fabricated samples were kept in moisture free environment and the other set was exposed to ambient air at room temperature for a long period of time that resulted in formation of native oxide prior to testing. The crystal structure and phase purity of the vanadium and the oxidized vanadium thin films were characterized by X-ray diffraction (XRD). The XRD results yield a preferential (1 1 0), and (2 0 0) orientation of the polycrystalline V films and (0 0 4) vanadium oxide (V 3 O 7 ). The vanadium films thickness were verified using field emission scanning electron microscopy and the films surface morphologies were inspected using atomic force microscopy (AFM). AFM images reveal surface roughness was observed to increase with increasing film thickness and also subsequent to oxidation at room temperature. The nanomechanical properties were measured by nanoindentation to evaluate the modulus and hardness of the vanadium and the oxidized vanadium thin films. The elastic modulus of the vanadium and the oxidized vanadium films was estimated as 150 GPa at 30% film thickness and the elastic modulus of the bulk vanadium target is estimated as 135 GPa. The measured hardness of the vanadium films at 30% film thickness varies between 9 and 14 GPa for the 100 and 50 nm films, respectively, exhibiting size effects, where the hardness increases as the film thickness decreases. The hardness of the oxidized films depicted less variation and is reported as ∼10 GPa at 30% film thickness for the three oxides. The scanning electron microscopy (SEM) imaging depicted a gradual progression of pile up as the film thickness increased from 75 to 100 nm. It is noticed that as the film thickness increases the films experience softening effect due to grain coarsening and the hardness values depict the hardness of the Si substrate at deep indents. [ABSTRACT FROM AUTHOR]

Ultra-thin Bi films show exotic electronic structure and novel quantum effects, especially the widely studied Bi (111) film. Using reflection high-energy electron diffraction and scanning tunneling microscopy, we studied the structure and morphology evolution of Bi (111) thin films grown on Bi2Se3. A strongly compressed, but quickly released in-plane lattice of Bi (111) is found in the first three bilayers. The first bilayer of Bi shows a fractal growth mode with flat surface, while the second and third bilayer show a periodic buckling due to the strong compression of the in-plane lattice. The lattice slowly changes to its bulk value with further deposition of Bi. [ABSTRACT FROM AUTHOR]

Reduction of transition metal oxides can greatly change their physical and chemical properties. Using deposition of WO3 as a case study, we demonstrate that reflection high-energy electron diffraction (RHEED), a surface-sensitive tool widely used to monitor thin-film deposition processes, can significantly affect the cation valence and physical properties of the films through electronbeam induced sample reduction. The RHEED beam is found to increase film smoothness during epitaxial growth of WO3, as well as change the electronic properties of the film through preferential removal of surface oxygen. [ABSTRACT FROM AUTHOR]

PbTe thin films on silicon substrates were prepared by an atomic layer deposition (ALD) for the first time, using lead (II) bis (2,2,6,6-tetramethyl-3,5-heptanedionato) and (trimethylsilyl) tellurid as ALD precursors, at deposition temperature as low as 170 °C. The formation of a PbTe thin film on the Si substrates was strongly dependent on the growth temperature. X-ray diffraction measurement indicated that thin films were polycrystalline and have characteristic face-centered cubic rock salt structure with a preferential (200) orientation. Scanning electron microscopy showed PbTe thin films were grown in the Volmer-Weber island mode. [ABSTRACT FROM AUTHOR]

The atomic structures that develop as a function of coverage during deposition of Bi on Ag(111) have been studied using low-temperature scanning tunneling microscopy, low-energy electron diffraction, and ab initio calculations. The growth process involves two sequential stages. At low coverage, Bi atoms are incorporated into the topmost layer of Ag(111), resulting in the formation of an Ag2Bi alloy confined to the surface and ordered (√3×√3)R30° Ag2Bi islands supported on Ag(111). This mode of accommodation of Bi was found to be energetically favorable based on ab initio total-energy calculations. At coverage above a critical value of 0.55 monolayers, the Ag2Bi alloy phase gradually converts into an ordered Bi (p×√3) overlayer structure supported on Ag(111). We postulate that the dealloying transition is likely driven by compressive strain induced by incorporation of large-size Bi atoms into Ag at a high coverage and the subsequent lack of miscibility of Ag and Bi bulk phases. After completion of the dealloying process, Bi(110) thin films can be grown epitaxially on top of Ag(111) with a chemically abrupt interface. [ABSTRACT FROM AUTHOR]

Abstract: Surfactant sputtering has been applied to modify the surface structure of Si substrates and to produce ultrathin metal-silicide films with nickel and platinum surfactants, utilizing the steady state coverage of a Si-substrate surface with surfactant atoms simultaneously during sputter erosion by combined ion irradiation and surfactant atom deposition. Si (100) substrates were eroded using 5keV Xe-ions and 10–30keV Ar ions at incident angles of 65° and 70° with fluences of up to 2×1018/cm2 under continuous sputter deposition of platinum and nickel from targets irradiated simultaneously by the same ion beam. These surfactant atoms form metal-silicides in the surface near region and strongly modify the substrate sputter yield and the surface nanostructure. Atomic force microscopy and scanning electron microscopy were carried out to observe a transition of surface topography from ripple to relief patterns, granular patterns or smooth surfaces. The Si and metal sputter yield as function of the steady state metal coverage were determined by combination of Rutherford-backscattering spectroscopy (RBS) and profilometry. The composition and the depth distributions of metal-silicide films were analyzed via high-resolution RBS and transmission electron microscopy. We show that RBS results in comparison with SRIM and TRIDYN sputter yield simulations allows us to identify the silicide surface structure on the nanometer scale. [Copyright &y& Elsevier]

Abstract: Nanostructured surface layers of titanium carbide and tungsten carbide were prepared on tetrahedral amorphous carbon (ta-C) films using the surfactant sputtering technique. Surfactant sputtering is a novel ion beam erosion technique, which utilizes the steady state coverage of a substrate surface with foreign atoms simultaneously during sputter erosion by combined ion irradiation and atom deposition. These foreign atoms act as surfactants, which strongly modify the substrate sputtering yield on atomic to macroscopic length scales. The novel technique allows smoothing of surfaces, the generation of novel surface patterns and nanostructures, controlled shaping of surfaces on the nanometer scale and the formation of ultra-thin compound surface layers. We have sputter eroded ta-C films using 5keV Xe ions under continuous deposition of either tungsten or titanium surfactants. This leads to the steady state formation of a W x C or a TiC/a-C nanocomposite surface layer of few nm thickness. Depending on the ion angle of incidence the layer is either smooth or nanostructured with a ripple- or dot-like surface topography. We have analyzed the surface topography, the composition and microstructure of the metal-carbon nanocomposites, and compare coverage dependent sputtering yields with SRIM and TRIDYN simulations. [Copyright &y& Elsevier]

Abstract: Pulsed laser deposition (PLD) was used to deposit FePt films onto single crystalline MgO substrates. When deposited at room temperature, films grow epitaxial within the A1 phase. Structure and magnetic properties were examined by X-ray diffraction, Rutherford Backscattering Spectrometry (RBS), magneto-optic Kerr effect, Mössbauer spectroscopy, and Magnetic Orientation Mössbauer Spectroscopy (MOMS). These measurements allow to exclude local ordering and reveal the anisotropic intrinsic and extrinsic magnetic properties. These results are discussed with respect to the texture and microstructure of these films. [Copyright &y& Elsevier]

Abstract: Ion-irradiation of ferromagnetic films induces pronounced changes of their microstructure and micromagnetism. The present study is devoted to the changes in the domain structure in 65–75nm electron-evaporated polycrystalline Ni films due to 200-keV Xe+ or 100-keV Ni+ implantation. For magnetic analysis, we combined magnetic force microscopy (MFM) and magneto-optical Kerr effect (MOKE); X-ray diffraction and Rutherford back-scattering spectroscopy served to characterize the microstructure of the films. After deposition, MFM indicated a pattern of magnetic ripples (with in-plane and perpendicular components of the magnetization). After ion irradiation, MOKE showed almost total in-plane remanence, and MFM confirmed the disappearance of the ripples at room temperature. The magnetic properties were correlated with the ion-induced changes in the strain in the as-deposited and ion-irradiated films. [Copyright &y& Elsevier]

Abstract: The mechanism of oxidation protection of NiCoCrAlY overlay coatings on the orthorhombic Ti2AlNb-based alloy (O alloy) Ti–22Al–26Nb (at.%) is described. While the bare alloy exhibited poor oxidation resistance at 800°C, adding NiCoCrAlY coatings significantly improved the oxidation resistance. However, serious interdiffusion between the coatings and the substrate resulted in rapid degradation of the coating system. Several reaction layers were formed at the coating/substrate interface by interdiffusion, and non-protective scales mainly of Cr2O3 and TiO2 were formed due to the degradation of the coating. In order to solve this problem, an Al2O3/Al interlayer was sandwiched into the coating system as a diffusion barrier. The isothermal and cyclic oxidation protection of the multilayer coating system on the Ti–22Al–26Nb substrate was evaluated at 800 and 900°C. The results indicated that the interdiffusion was much suppressed, and the duplex coating system demonstrated improved oxidation resistance on the Ti–22Al–26Nb substrate, with a thin and adherent protective α-Al2O3 scale forming on the surface. [Copyright &y& Elsevier]

We have investigated the correlation between nanoscale surface ripple patterns and the magnetic texture of polycrystalline iron and nickel thin films. The ripple patterns were created by ion beam sputter erosion of films evaporated on Si substrates with 5 keV Xe ions under grazing incidence and fluences between 1015 and 1017 cm-2. The as-deposited films with an rms roughness of about 1 nm are magnetically isotropic. Sputter erosion reduced the coercive field of the films for all erosion conditions investigated. Sputter erosion at an incidence angle of 80? with respect to the surface normal produces rather smooth films and for ion fluences exceeding 1 x1016 cm-2 formation of ripples parallel to the ion beam direction with wavelength between 30 and 80 nm is observed. MagnetoopticalKerr effect (MOKE) measurements reveal a pronounced uniaxial magnetic anisotropy of the only 1-2 nm thin irradiated surface region of the films with orientation parallel to the ripple orientation and also parallel to the ion beam direction. Almost complete sputter erosion of Fe films resulted in the formation of Fe nanorods oriented parallel to the ion beam direction with 100% uniaxial magnetic texture. [ABSTRACT FROM AUTHOR]

Thin films of Al and Mn multilayers were synthesized using thermal evaporation under high vacuum conditions. The whole film thickness containing three bilayers of Al and Mn is about 120 nm. The global concentration of the samples was varied between 10 and 46.5 at.% Mn, by changing the thickness of the bilayer. The as-evaporated samples were heat treated at different temperatures (473, 623, 823 and 873 K) for 2 and 8 h to investigate the interfacial diffusion induced phase transformations in the multilayered thin films. Transmission electron microscopy (TEM) has been mainly used to characterize the crystalline structure of a variety of phases revealed on annealing, such as μ, λ and φ phases up to 823 K, δ phase at 823 K and T6 phase at 873 K. The occurrence of a variety of structures on annealing has been attributed to the interfacial reactions at the Al–Mn bilayers, and, therefore, the global composition of the composite films is not significant during the process of phase transformations. The crystallographic relationships of Al–Mn approximant structures of the decagonal quasicrystal are discussed to understand the evolution and stability of the T6 phase at high temperature. [ABSTRACT FROM AUTHOR]

The microstructure of lanthanum manganite (La1-xMnO3-delta) thin film on strontium titanate (SrTiO3) substrate fabricated by liquid chemical vapour deposition has been studied by transmission electron microscopy. Both La1-xMnO3-delta and SrTiO3 have a perovskite structure with lattice misfit about 1% but there is no evidence for correlation of the density of the misfit dislocation and misfit. In the vicinity of the interface between La1-xMnO3-delta and SrTiO3, the misfit is accommodated by a distortion of the lattice of La1-xMnO3-delta. At the areas not adjacent to the interface of La1-xMnO3-delta-SrTiO3, small particles, which can be identified as MnO, are found to be associated with the misfit between La1-xMnO3-delta and SrTiO3. The MnO phase is unstable with respect to La1-xMnO3-delta. The growth of a thin film of La1-xMnO3-delta on SrTiO3 is epitaxial and an orientation relationship is (100)La1-xMnO3-delta//(100)SrTiO3//(100)MnO and [010]La1-xMn03-delta//[010]SrTi03//[010]Mn0. The interface of La1-xMnO3-delta-SrTiO3 is composed of Ti and Mn atoms plus oxygen. [ABSTRACT FROM AUTHOR]

β-Ga2O3 is attracting considerable attention for applications in power electronics and deep ultraviolet (DUV) optoelectronics owing to the ultra-wide bandgap of 4.85 eV and amendable n-type conductivity. In this work, we report the achievement of Si-doped β-Ga2O3 (Si:β-Ga2O3) thin films grown on vicinal α-Al2O3 (0001) substrates with high electrical conductivity and DUV transparency of promising potential as transparent electrodes. The use of Al2O3 substrates with miscut angles promotes step-flow growth mode, leading to substantial improvement of crystalline quality and electrical properties of the Si:β-Ga2O3 films. A high conductivity of 37 S·cm−1 and average DUV transparency of 85% have been achieved for 0.5% Si-doped film grown on a 6° miscut substrate. High-resolution x-ray and ultraviolet photoemission spectroscopy were further used to elucidate the surface electronic properties of the grown Si:β-Ga2O3 films. An upward surface band bending was found at the surface region of Si:β-Ga2O3 films. Interestingly, all the Si:β-Ga2O3 films have a very low work function of approximately 3.3 eV, which makes Si:β-Ga2O3 suitable materials for efficient electron injection. The present Si:β-Ga2O3 films with high conductivity, DUV transparency, and low work function would be useful as the DUV transparent electrode to develop advanced DUV optoelectronic devices. [ABSTRACT FROM AUTHOR]

We report on the optoelectronic properties of the hydrogenated nanocrystalline silicon (nc-Si:H) thin film containing large density of nanometer grains and voids. By comparison with the bulk silicon, strong optical absorption and high photocurrent are found in the nc-Si:H thin film and attributed to the enhancement of the optical absorption cross section and good carrier conductivity in the nanometer grains and voids. The observed strong photocurrent signals can be well described by the extended diffusion-recombination model. The high photocurrent response may facilitate the fabrication of infrared photodetector by a single layer of nc-Si:H thin film on a glass substrate, which shows superiority to the traditional amorphous Si photodetector with a diode or Schottky-barrier structure constructed by multilayer films on the crystalline Si substrate. [ABSTRACT FROM AUTHOR]

In combination with dephasing and weak localization theories, we have presented a detailed magnetotransport investigation for the electron dephasing characteristics in hydrogenated nanocrystalline silicon thin films. It is found that the experimental magnetoconductivity can be well fitted by an integration of diffusive Fermi surface and scaling models, taking into account both the two-dimensional quasielastic small energy transfer via scattering of localized electrons on potential barriers of several different dots (Nyquist mechanism) and three-dimensional inelastic phonon scattering contribution. The dephasing time and length have also been extracted with a temperature exponent p≈1.2 for the natural semiconductor quantum dot system. [ABSTRACT FROM AUTHOR]

To prolong the service lifetime of artificial joint, it is imperative to improve mechanical and tribological properties of the prosthetic materials, which could be achieved by adding a surface protective layer. The TiCuN solid-solution coating is highlighted in this work for this application. Higher hardness, lower friction coefficient, and enhanced wear resistance are demonstrated with TiCuN solid-solution coating with 5.2 at% Cu dopant, comparing to pure TiN and TiN/Cu nano-composite coatings. In addition, the live/dead staining and morphology of cells cultured on the surface of TiCuN solid-solution coating point out that the TiCuN coating exhibits excellent biocompatibility, which could be potentially applied as the artificial joint protective coating in human body. [ABSTRACT FROM AUTHOR]

Superconducting Tl2CaBa2Cu2Oy thin films have been successfully grown on the single-crystal sapphire (1102) substrate by using the metalorganic chemical vapor deposition technique. The growth rate of the films was about 5 μm/h. The as-deposited film was post-annealed in a partially sealed ceramic crucible in the presence of a Tl2Ca2Ba2Cu3Oy pellet to achieve the superconducting phase. The x-ray data show strong diffraction from the Tl2CaBa2Cu2Oy superconducting phase in addition to the trace amounts of Ca2CuO3 and BaCO3. Superconducting transition temperatures with onset above 100 K and zero resistance at 94 K can be obtained by further heat treatment at 500 °C in oxygen. [ABSTRACT FROM AUTHOR]

A model for calculation of thermal conductivity of thin films of silicon and germanium is presented on the basis of solving the Boltzmann equation in the time relaxation approximation. The unique feature of this model is the application of recent achievements in determination of the time of phonon–phonon interactions obtained from "first principles" and also the use of real dispersion curves and the propagation velocities of phonons with different polarization. The proposed approach contains no averaging and fitting parameters, which already for more than half a century and until now have been common in calculations of thermal conductivity of macroscopic bodies and nanostructures. A detailed qualitative and quantitative comparison of results of calculations by the "classical" and "updated" models is carried out. Problems in the methods for calculating thermal conductivity for simulation of new structures in advanced semiconductor devices and ways of their further development are set forth. [ABSTRACT FROM AUTHOR]

Highlights: [•] Silicide phases formation in Co/Si system during annealing was investigated. [•] Thin Co films were deposited on crystalline or pre-amorphized Si wafers. [•] Argon ions generate damage region which represents diffusion barrier. [•] The phase sequence depends on the concentration of the reacting species. [•] The observed phase transitions are consistent with predictions of EHF model. [ABSTRACT FROM AUTHOR]

Fe70Ga30 magnetic nano thin films of different thicknesses were successfully fabricated by ion beam deposition coating on Si/SiO2 substrates. The crystal structure of Fe70Ga30 magnetic nano thin films were characterized by Grazing incidence X-ray diffraction (GIXRD). Surface morphology is studied using Atomic Force Microscopy (AFM). The magnetic properties of nano thin films have been measured by Vibrating Sample Magnetometer (VSM). The result reveals that the nano thin films have good soft magnetic properties. We measured the current-voltage (I-V) curves of Fe70Ga30 nano thin films, the behavior of resistance switching by more than an order of magnitude was obtained. The measurement performed on Fe70Ga30 nano thin films reveal that the resistant switching behavior is reversible and the transformation occurs between high (low) resistance states. The manipulation could be attributed to the Coulomb blockade effect. The existence of anomalous Hall effect was found during the Hall effect test on the nano thin films surface. The surface carrier density of Fe70Ga30 nano thin films changed when Hall effect test was performed resulting in magnetic switching. [ABSTRACT FROM AUTHOR]

Molecular dynamics simulation has been performed to study the splitting of the second peak in pair correlation functions of quasi-two-dimensional disordered film. A quasi-two-dimensional inhomogeneous structural model, which contains both crystal-like and disordered regions, supports the hypothesis that the splitting of the second peak is result of a statistical average of crystal-like and disordered structural regions in the system, not just the amorphous structure. The second-peak splitting can be viewed as a prototype of the crystal-like peak exhibiting distorted and vestigial features. [ABSTRACT FROM AUTHOR]

The present study deals with irradiation effects induced by xenon ions (Xe + ) on titanium nitride (TiN) thin films. TiN films thickness of 260 nm obtained by using dc reactive sputtering were irradiated with 400 keV Xe ions. The irradiation doses were 5 × 10 15 , 10 × 10 15 , 15 × 10 15 and 20 × 10 15 ions/cm 2 . The properties of irradiated films varying with ion fluence are investigated by means of Rutherford backscattering spectrometry, X-ray diffraction, transmission electron microscopy and spectroscopic ellipsometry. It was found that the Xe ions induce contraction and rhombohedral distortion of TiN lattice. The columnar structure was partially destroyed after irradiation, which introduce up to 1.5 at.% of Xe within the structure mostly concentrated around the projected ion range. The generation of defects due to the presence of heavy ions changes the optical constants of implanted films. It was found that the optical band gap of TiN films was reduced after xenon ion implantation. [ABSTRACT FROM AUTHOR]

Abstract: The morphological, elemental distribution and electrical performance effects of increasing the Cu(In,Ga)Se2 (CIGS) growth substrate temperature are studied. While the increased substrate growth temperature with no other modifications led to increased CIGS grain size, it also resulted in depth profile flattening of the [Ga]/([Ga]+[In]) ratio. Tuning the Ga profile in the high temperature process led to a more desirable [Ga]/([Ga]+[In]) depth profile and allowed a comparison between high and standard temperature. Devices prepared at higher temperature showed an improved grain size and the electrical performance is very similar to that of the reference sample prepared at a standard temperature. [Copyright &y& Elsevier]

The application of pure molybdenum disulfide (MoS 2) film as solid lubricant is limited due to its low hardness and high friction coefficient in the atmosphere. It is reported that the hardness can be improved by doping metal elements into MoS 2 , while the friction coefficient can be reduced by the formation of curved micro-nano structure of MoS 2. Thus, doping metal atoms with catalytic properties such as Cu into MoS 2 , to form turbulence-like micro-nano structure has the potential to simultaneously increase hardness and decrease friction coefficient. In our work, we deposit Cu/MoS 2 films with turbulence-like structure (TL-MoS 2) using magnetron sputtering technology, which exhibit higher hardness and lower friction coefficient in the atmosphere than pure MoS 2. When the Cu content reaches 15.9 at.%, Cu atoms with catalytic properties induce the formation of curved S-Mo-S layers and forms TL-MoS 2. Cu incorporation results in the change of preferred orientation of film from (100) plane for pure MoS 2 to (002) plane for Cu/MoS 2 , accompanied by the densification of the structure. The hardness of Cu/MoS 2 is approximately 10 times higher than that of pure MoS 2 due to the denser structure and TL-MoS 2. It is worth mentioning that TL-MoS 2 contributes to the improvement of the hardness by extending the strength of the planar network into a three-dimension space network. Moreover, TL-MoS 2 prevents oxidation and promotes the formation of MoS 2 tribofilm during sliding, leading to a significant reduction of the friction coefficient to 0.07 ± 0.01 in the atmosphere, which is 3 times lower than that of pure MoS 2 film. Our strategy provides guidance for preparing metal doped MoS 2 films with excellent mechanical and tribological properties for application in the atmosphere. • Doping Cu into MoS 2 induces the formation of turbulence-like MoS 2. • The hardness of Cu/MoS 2 film is 10 times higher than that of pure MoS 2 film. • The COF of Cu/MoS 2 film in the atmosphere is much lower than that of pure MoS 2 film. • The Cu/MoS 2 film has the potential as lubricious and protective coating in the atmosphere. [ABSTRACT FROM AUTHOR]

Abstract: We investigated the effects of sputter erosion of iron thin films grown on silica and silicon substrates by electron beam evaporation. Iron thin films with typical thickness of 100 nm were sputter eroded using Xe ions with energies of 4 keV up to 450 keV, substrate temperatures of 100 K and 300 K, ion fluences up to 1×1017 ions /cm2 and angles of incidence to the surface normal varied between 0° and 80°. The surface topography was monitored by atomic force microscopy and the magnetic properties of the near-surface region were monitored using magneto optical Kerr effect. The as-deposited nanocrystalline films have an rms roughness of 1 nm and are magnetically almost isotropic. After sputter erosion the rms roughness increases up to 3 nm, depending on the irradiation parameters, and the films become magnetically softer. We observe ripple formation with orientation parallel to the direction of the incident ion beam, as well as uniaxial magnetic anisotropy, for ion irradiation at incidence angles of 80°. [Copyright &y& Elsevier]

Thin polycrystalline films of permalloy (Ni79Fe21) and permendur (Co50Fe50) have been irradiated with Xe-ions to fluences of 1014–1016 ions/cm2. Ion-induced structural and magnetic modifications have been measured by grazing angle X-ray diffraction, Rutherford backscattering and magneto-optical Kerr effect. In the case of permendur, the Xe-ion implantation first reduced the coercivity, because of stress relaxation, while higher ion fluences increased the coercivity due to pinning centers generated in the film. The ion irradiation aligned the in-plane easy axis of the magnetization along the direction of the external magnetic field during implantation. Phase shifts obtained from magnetic force microscopy confirmed these modifications. The effects of Xe-ion irradiation in permalloy films are much weaker and underline the importance of magnetostriction in the variation of the coercivity and anisotropy. [ABSTRACT FROM AUTHOR]

By using first principles total energy calculations, the surface energies of (100), (110), (111) and (211) surfaces of Mo before and after adsorbing ultrathin films of Rh have been presented. The results show that in the case of clean Mo surfaces Mo(111) is stable against faceting to Mo(211), Mo(110) and Mo(100), while after adsorbing one physical monolayer of Rh, the surface energies of all the four surfaces decrease, and Mo(111) can facet to {211}, but not to {110} and {100} surfaces. [ABSTRACT FROM AUTHOR]

We report the synthesis of epitaxial As-doped ZnO and Mn-doped (ZnAs)O films by pulsed-laser deposition technique. The grain size in (ZnAs)O films decreases from 40 to less than 10 nm upon Mn doping, illustrating that Mn acts as a potential catalyst to create nanosize grains. Temperature dependent electrical resistance shows metal-insulator transition and metal-semiconductor transition (MST) at 165 and 115 K, respectively, in (ZnAs)O, although Mn doping suppresses MST completely. Both ionization efficiency on oxygen vacancies and percolation of charge carriers may be responsible for such transitions. In addition, electrical conduction in these films shows strong aging effects. [ABSTRACT FROM AUTHOR]