Ion Beam Assisted Deposition Research Articles

Optical and stress properties of ZrO2/SiO2 and TiO2/SiO2 anti-reflective coatings deposited by ion-beam-assisted deposition on a flexible substrate

Dielectric films of ZrO2,TiO2, and SiO2 were deposited on flexible polycarbonate (PC) and polyethylene terephthalate (PET) substrates by using ion-beam-assisted deposition (IBAD). Each layer had a thickness ranging from 30 to 210 nm. The optical and anisotropic stress properties were investigated. Two anti-reflective coatings (ARCs), ZrO2/SiO2 and TiO2/SiO2, were selected and deposited on the PET flexible substrate. The anisotropic stresses of the single layer and ARCs were measured using a phase-shifting moiré interferometer. Experimental results showed that the optimal oxygen flow rates for the ZrO2,TiO2, and SiO2 films deposited with IBAD were 10, 10, and 15 sccm, respectively. The refractive index (n) was TiO2(2.37)>ZrO2(2.05)>SiO2(1.46), and the extinction coefficient (k) for all samples was below 10−3. The thermal expansion coefficient of the PC substrate was three times that of the PET substrate, and the high-refraction ZrO2 and TiO2 single-layer films presented cracks and distortions on the PC substrate. Only the low-refractive-index SiO2 sample did not present cracks. The three dielectric films did not crack or distort when deposited on the PET substrate. The anisotropic stress analysis provided the maximum principal and shear stresses for the three dielectric films on the PET substrate. Therefore, the maximum principal stress of the 210 nm single-layer film on a PET substrate is TiO2>ZrO2>SiO2. It was also discovered that the principal stress of the AR multilayer film is significantly decreased due to the damping stacking effect (DSE) of the high- and low-refractive-index materials, ZrO2/SiO2 ARC (−297.3MPa)>TiO2/SiO2ARC(−132.6MPa). Thus, the high packing density of TiO2 gives a better DSE than ZrO2.

Comprehensive study of epitaxial (Nd,Eu,Gd)Ba2Cu3O7−δ films grown on textured templates

We report the successful epitaxial growth and comprehensive study of structural and superconducting properties of (Nd,Eu,Gd)Ba2Cu3O7−δ films with a thickness of up to 1.2 μm prepared by on-axis pulsed laser deposition on SrTiO3 (STO) single crystals as well as on ion-beam-assisted deposition (IBAD) and rolling-assisted biaxially textured substrate (RABiTS)-based metal templates. X-ray diffraction demonstrates the epitaxial quality of the grown films on both single crystalline substrates and metal-based templates. In addition, no significant changes in surface morphology were found with increasing thickness for films on all types of substrates. On all substrates, a T c value of about 89 K was observed, however, significant inhomogeneities indicating small superconducting volume were found for all films on STO. In general, the best transport characteristics over a wide range of magnetic fields and temperatures were observed for thicker films on IBAD-MgO and RABiTS templates, respectively. The J c values at 77 K for the films on IBAD-MgO templates are comparable to YBCO films, but inferior in the low temperature region and high magnetic fields, whereas the films on RABiTS and especially on STO showed much lower J c over the entire temperature and magnetic field range. A maximum pinning force of about 7 GN·m−3 at 65 K was found for the 900 nm thick films on IBAD-MgO template. In addition, the pinning mechanism seems to depend on both temperature and type of substrate. In general, no correlation between local microstructure and transport characteristics was revealed for NEG films on both metal templates.

Methods of active friction control in the presence of lubricant compositions with mesogenic additives

Purpose of research. The aim of the study is to systematize the latest literature data related to the modulation of the friction coefficient by external fields when using lubricant compositions with liquid crystal mesogens and polymer composites.Methods. The article considers the methods of tribological tests using various schemes of friction pairs (cylinder-disk, pin-on-disk). Some commonly used methods of applying coatings to the elements of friction pairs are considered: ion beam-assisted deposition, chemical and physical thermal spraying, molecular layer deposition, photopolymerization, etc. Of the discussed methods of characterizing tribosystems, the following are indicated: dielectric spectroscopy, Raman scattering, polarization optical microscopy, nuclear-physical methods (positron annihilation spectroscopy and Xray diffraction).Results. The article systematizes modern trends in the development of modulated modes of operation of tribological circuits with lubricant compositions containing liquid crystals and polymer composites. The following approaches are used to implement active control of the friction coefficient: 1) modulation of friction by an electric field, 2) modulation of friction by a temperature field, and 3) modulation of friction on optical gratings under light irradiation. These approaches take into account the changed characteristics of the lubricant associated with the use of mesogenic additives, modes of exposure to electromagnetic and thermal fields, electrical characteristics, geometry of the surface of friction pairs, and provide the values of tribological characteristics (friction coefficient and wear) that are achieved as a result of friction modulation.Conclusion. A positive effect of mesogenic additives of liquid crystals and polymers on tribological characteristics with active control of the friction coefficient has been established: a decrease in the friction coefficient is observed, which helps to reduce material wear.

Optimization of Ion Beam-Assisted Deposition Process for Y2O3 Film to Enhance Plasma Resistance

Optimization of Ion Beam-Assisted Deposition Process for Y2O3 Film to Enhance Plasma Resistance

Gas Cluster Ion Beam-Assisted Deposition for Fabricating Dry Multilayers Containing Enzyme and Substrate with On-Demand Release.

Gas cluster ion beam (GCIB)-assisted deposition is used to build multilayered protein-based structures. In this process, Ar3000-5000+ clusters bombard and sputter molecules from a reservoir (target) to a collector, an operation that can be sequentially repeated with multiple targets. The process occurs under a vacuum, making it adequate for further sample conservation in the dry state, since many proteins do not have long-term storage stability in the aqueous state. First of all, the stability in time and versatility in terms of molecule selection are demonstrated with the fabrication of peptide multilayers featuring a clear separation. Then, lysozyme and trypsin are used as protein models to show that the activity remaining on the collector after deposition is linearly proportional to the argon ion dose. The energy per atom (E/n) of the Ar clusters is a parameter that was also changed for lysozyme deposition, and its increase negatively affects activity. The intact detection of larger protein molecules by SDS-PAGE gel electrophoresis and a bioassay (trypsin at ≈25 kDa and glucose oxidase (GOx) at ≈80 kDa) is demonstrated. Finally, GOx and horseradish peroxidase, two proteins involved in the same enzymatic cascade, are successively deposited on β-d-glucose to build an on-demand release material in which the enzymes and the substrate (β-d-glucose) are combined in a dry trilayer, and the reaction occurs only upon reintroduction in aqueous medium.

Microstructural characterization of nanocrystalline hexagonal boron nitride thin films deposited by ion-beam assisted pulsed laser deposition

In recent years, hexagonal boron nitride (hBN) thin films have garnered considerable attention across various fields, including electronics, anti-corrosion coatings, tribology, and optoelectronics. Boron nitride films produced via physical vapor deposition typically result in amorphous microstructure and suffer from issues such as cracking and delamination. The synthesis of crystalline hBN thin films typically demands higher processing temperatures, toxic gas precursors, and catalytic metal substrates. Hence, this research aims to produce crystalline hBN films at relatively lower temperatures without toxic gas precursors. hBN thin films were deposited on silicon (100) substrates at 600 °C using an ion beam-assisted pulsed laser deposition. The study explores the microstructural evolution and surface morphology of deposited films under different Ar:N2 gas mixtures (ranging from 0% to 100% N2) and varying ion beam energies (from 0 to 400 eV). Microstructural analysis showed the hBN nanocrystallite formation in films deposited with N2 content of 50% and higher and an ion beam energy equal to or exceeding 200 eV, and the crystallite size was measured to be ∼24±8 nm. Raman spectra, grazing incidence X-ray diffraction, and transmission electron microscopy confirm the presence of hBN phase in as-deposited films. Films deposited with an N2 content of ≥50% and ion beam energy of ≥200 eV showed improved crystallinity, increased island size, and density of hBN nanocrystallites. The addition of ion bombardment comparatively made films rougher due to grain growth and formation of larger hBN nanoislands, and surface roughness increased with an increase in N2 content and ion beam energy. The results indicate that the ion beam bombardment facilitates nanograin formation and improves the crystallinity of hBN films even at lower deposition temperatures, offering the promise of advancing their use into practical applications across various fields.

Optical, Electrical, Structural, and Thermo-Mechanical Properties of Undoped and Tungsten-Doped Vanadium Dioxide Thin Films.

The undoped and tungsten (W)-doped vanadium dioxide (VO2) thin films were prepared by electron beam evaporation associated with ion-beam-assisted deposition (IAD). The influence of different W-doped contents (3-5%) on the electrical, optical, structural, and thermo-mechanical properties of VO2 thin films was investigated experimentally. Spectral transmittance results showed that with the increase in W-doped contents, the transmittance in the visible light range (400-750 nm) decreases from 60.2% to 53.9%, and the transmittance in the infrared wavelength range (2.5 μm to 5.5 μm) drops from 55.8% to 15.4%. As the W-doped content increases, the residual stress in the VO2 thin film decreases from -0.276 GPa to -0.238 GPa, but the surface roughness increases. For temperature-dependent spectroscopic measurements, heating the VO2 thin films from 30 °C to 100 °C showed the most significant change in transmittance for the 5% W-doped VO2 thin film. When the heating temperature exceeds 55 °C, the optical transmittance drops significantly, and the visible light transmittance drops by about 11%. Finally, X-ray diffraction (XRD) and scanning electron microscope (SEM) were used to evaluate the microstructure characteristics of VO2 thin films.

Optimization of Ion Beam-Assisted Deposition Process for Y<sub>2</sub>O<sub>3</sub> Film to Enhance Plasma Resistance

A ceramic-based plasma etcher window (Lid) requires robust resistance to plasma, especially when exposed to harsh fluorine-based plasma conditions. In this study, a Y<sub>2</sub>O<sub>4</sub> film was deposited using e-beam evaporation with ion beam-assisted deposition (IBAD), and the physical properties of the IBAD-based Y<sub>2</sub>O<sub>4</sub> coating film were thoroughly examined to enhance the mechanical and chemical resistance of the ceramic part, including the Y<sub>2</sub>O<sub>4</sub> film, against etching plasma. The hardness and surface morphology of the IBADbased Y<sub>2</sub>O<sub>4</sub> could be precisely controlled by various deposition processing parameters, such as beam voltage, beam current, and Ar/O2 gas ratio. Following the IBAD deposition of the Y<sub>2</sub>O<sub>4</sub> film, a plasma etching process (Ar/CF<sub>4</sub> mixture gases with 150 W RF power for 60 minutes) was applied to evaluate the plasma resistance of the deposited Y<sub>2</sub>O<sub>4</sub> coating film. The surface morphology characteristics of the Y<sub>2</sub>O<sub>4</sub> films were compared using atomic force microscopy, and their grain size was studied through scanning electron microscopy image analysis. Furthermore, a nanoindenter was used to determine the hardness of the Y<sub>2</sub>O<sub>4</sub> film. These results suggest that optimizing the IBAD coating process requires an in-depth study that fully considers the correlation between deposition processing parameters and physical properties. This optimization can be instrumental for enhancing the durability of the ceramic part.

Effect of PVD deposition method on indentation and friction wear characteristics with hydrogen embrittlement of CrN coated stainless steel for electric vehicle hydrogen valves

In this investigation, a chromium nitride layer was deposited on general austenite stainless steel (UNS S31603) by means of the physical vapor deposition coating method to improve the hardness, wear resistance, and hydrogen embrittlement resistance. Accordingly, the purpose of this investigation is to study the effect of different physical deposition methods on mechanical characteristics due to hydrogen embrittlement. Both the indentation and friction characteristics of the chromium nitride layer with in response to hydrogen embrittlement were examined. The ion beam-assisted deposition (IBAD) and arc ion plating (AIP) methods were used to densely deposit the coating layer with a thickness of approximately 2.0∼2.5 μm, and the hardness increased by around 1180.9 HV and 1638.6 HV, respectively, when compared with the base material (292.6 HV). In terms of the coating layer deposited using the IBAD method, all the base material was exposed after hydrogen embrittlement for 3 h, whereas in the case of the coating deposited using the AIP method, the base material began to be exposed locally following hydrogen embrittlement for 12 h. For the IBAD- and AIP-deposited coatings, the average friction coefficient was calculated as 0.52 and 0.34, respectively. In the case of the coating layer deposited using the IBAD method, the average friction coefficient increased by 0.29 after hydrogen embrittlement for 3 h, whereas the average friction coefficient of the coating layer deposited using the AIP method increased by 0.04 after hydrogen embrittlement for 48 h. Therefore, it can be seen that the AIP method is significantly better than IBAD in terms of mechanical characteristics with hydrogen embrittlement.

Stress mechanism analysis by finite element method for different dielectric films deposited with ion-beam assisted deposition on flexible substrates

In this study, an investigation was made into the optical and stress properties of four dielectric films: silicon dioxide (SiO2), titanium dioxide (TiO2), tantalum pentoxide (Ta2O5) and niobium pentoxide (Nb2O5). This was because they are commonly used in the optoelectronic and semiconductor devices. The classification of these stress properties includes tensor & compressive, thermal & intrinsic, and principal & shearing. The stress mechanism of these dielectric films deposited on polyethylene terephthalate (PET) and polycarbonate (PC) flexible substrates with ion-beam assisted deposition (IBAD) was investigated by the finite element method (FEM). Meanwhile, the equivalent room temperature (ERT) of FEM was used for the analysis of the intrinsic stresses, and then the methods of home-made phase-shifting shadow moiré interferometer and Mohr circle were employed to analyze the anisotropic principal and shearing stresses. The results demonstrated that the residual stress of these dielectric films could get broken on the PC flexible substrate. However, only all of the SiO2/PC films were measured. Also, the residual stress on PET flexible substrate could change from the tensile stress to the compressive one when the thickness of the film increased. However, only all of the Ta2O5/PET films got compressed when the film thickness increased. Therefore, the anisotropic stress of the four dielectric films on the PET substrate suggests that both the maximum principal and shearing stresses should be Ta2O5>TiO2≥Nb2O5>SiO2. They are proportion to Q (elastic-energy/mole). The FEM method combined with the high-order polynomial fitting curvature could obtain the intrinsic stress and yield the error within 2.47 %.

Edge cracking behavior of Y2O3 films based on the stress intensity factor

Hastelloy C-276 alloy is the preferred substrate for YBa2Cu3O7-δ (YBCO) coated conductors prepared by Ion-beam-assisted deposition (IBAD) route, but its surface is too rough to meet application requirements. Y(CH3COO)3·4H2O precursor solution has a low flattening efficiency, and its film edges are prone to crack formations. In this paper, a model for the stress intensity factor was established to study the effect of the presence of cracks on film stress. The simulation results showed that increasing the coating thickness reduced the overall stress, but increased the stress concentration at the crack. The larger bottom layer defects also made it easier for cracks to be generated. Then, 10-m long Hastelloy C-276/Y2O3 strips were prepared by colloidal-solution deposition planarization (CSDP), with an average surface roughness Rq of 0.427 and only 10 coating layers. This improved the flattening efficiency by 40 %, and a CeO2 layer with a good biaxial texture was finally prepared.

Preparation of MgO Self-Epitaxial Films for YBCO High-Temperature Coated Conductors.

Ion beam-assisted deposition (IBAD) has been proposed as a promising texturing technology that uses the film epitaxy method to obtain biaxial texture on a non-textured metal or compound substrate. Magnesium oxide (MgO) is the most well explored texturing material. In order to obtain the optimal biaxial texture, the actual thickness of the IBAD-MgO film must be controlled within 12nm. Due to the bombardment of ion beams, IBAD-MgO has large lattice deformation, poor texture, and many defects in the films. In this work, the solution deposition planarization (SDP) method was used to deposit oxide amorphous Y2O3 films on the surface of Hastelloy C276 tapes instead of the electrochemical polishing, sputtering-Al2O3 and sputtering-Y2O3 in the commercialized buffer layer. An additional homogeneous epitaxy MgO (epi-MgO) layer, which was used to improve the biaxial texture in the IBAD-MgO layer, was deposited on the IBAD-MgO layer by electron-beam evaporation. The effects of growth temperature, film thickness, deposition rate, and oxygen pressure on the texture and morphology of the epi-MgO film were systematically studied. The best full width at half maximum (FWHM) values were 2.2° for the out-of-plane texture and 4.8° for the in-plane texture for epi-MgO films, respectively. Subsequently, the LaMnO3 cap layer and YBa2Cu3O7-x (YBCO) functional layer were deposited on the epi-MgO layer to test the quality of the MgO layer. Finally, the critical current density of the YBCO films was 6 MA/cm2 (77 K, 500 nm, self-field), indicating that this research provides a high-quality MgO substrate for the YBCO layer.

Anisotropic stress mechanisms for different dielectric multi-layer films deposited by ion-beam assisted deposition on flexible substrates

This study simulates and tests various prototype multi-layer films on polyethylene terephthalate (PET) and polycarbonate (PC) substrates. The optical and stress response properties of three commonly used optoelectronic anti-reflector (AR) coatings (TiO2/SiO2)2, (Ta2O5/SiO2)2 and (Nb2O5/SiO2)2 were determined. A lab-designed phase-shifting shadow moiré interferometer and Mohr circle approach were used to collect and interpret data. Results showed that the refractive indices of the four different dielectric films were 2.24(TiO2) > 2.23(Nb2O5) > 2.1(Ta2O5) > 1.44(SiO2). The transmittances of the three different AR coatings, in decreasing order, were 95.28%(Ta2O5/SiO2)2 > 94.86%(TiO2/SiO2)2 > 94.03%(Nb2O5/SiO2)2. The maximum shear stress of three different AR coatings, in decreasing size, were (Nb2O5/SiO2)2 > (Ta2O5/SiO2)2 > (TiO2/SiO2)2, for both the PET and PC substrate; however, the maximum principal stresses of three different AR coatings were tensors for the PET substrate, and compressive for the PC substrate. The principal stresses recorded were -916 MPa (Nb2O5/SiO2)2 > 438 MPa (Ta2O5/SiO2)2 > 346 MPa (TiO2/SiO2)2 for PET, and -951 MPa (Nb2O5/SiO2)2 > -838 MPa (Ta2O5/SiO2)2 > -766 MPa (TiO2/SiO2)2 for PC. The different elasticity moduli (ΔE) and relative elasticity between the different film layers may potentially be used to mitigate stress relief in multilayer coatings.

Scalable High-Mobility Graphene/hBN Heterostructures.

Graphene-hexagonal boron nitride (hBN) scalable heterostructures are pivotal for the development of graphene-based high-tech applications. In this work, we demonstrate the realization of high-quality graphene-hBN heterostructures entirely obtained with scalable approaches. hBN continuous films were grown via ion beam-assisted physical vapor deposition directly on commercially available SiO2/Si and used as receiving substrates for graphene single-crystal matrixes grown by chemical vapor deposition on copper. The structural, chemical, and electronic properties of the heterostructure were investigated by atomic force microscopy, Raman spectroscopy, and electrical transport measurements. We demonstrate graphene carrier mobilities exceeding 10,000 cm2/Vs in ambient conditions, 30% higher than those directly measured on SiO2/Si. We prove the scalability of our approach by measuring more than 100 transfer length method devices over a centimeter scale, which present an average carrier mobility of 7500 ± 850 cm2/Vs. The reported high-quality all-scalable heterostructures are of relevance for the development of graphene-based high-performing electronic and optoelectronic applications.

Biaxial texture establishment and evolution in IBAD-MgO films under different ion-to-atom ratios

MgO is a critical layer for the high-temperature superconducting coated conductor whose quality and performance greatly depend on the texturization of the MgO layer. In this paper, we have successfully grown MgO thin films on Y2O3 seed layers by the ion beam-assisted deposition (IBAD) method and systematically investigated the effects of ion-to-atom ratios (IARs) on the texture evolution of MgO films. It was found that better textured IBAD-MgO films could be obtained at thinner thickness with the increase of IAR. At low IARs of 0.2, 0.34, and 0.47, biaxial texture without c-axis tilting features could be observed in MgO films with thicknesses up to 50–60 nm, which is the highest value in our study. On the other hand, for high IARs of 0.66 and 0.79, the biaxial texture of MgO films was optimized at 13 nm and 7 nm, but completely disappeared at 26 nm and 12 nm, respectively. The differentiation in the texture evolution process under different IARs provides a crucial reference for elucidating the growth mechanism of IBAD-MgO. Moreover, these unambiguous experimental results also provide an excellent reference for the industrial production of HTS-coated conductors.

Insights into protective performance of CoCrNi medium entropy alloy coating subjected to supersonic micro-ballistic impact

Medium- and high-entropy alloys (MEAs and HEAs) coatings have attracted increasing attention owing to their exceptional mechanical properties and potential applications in structures protective from supersonic microparticle impact. However, there are no experimental insights into their protective performance. In this study, we fabricated high-quality amorphous CoCrNi MEA coatings with a thickness of 4.5 μm on the rigid and flexible substrates through ion beam-assisted deposition. Based on nanoindentation and laser-induced supersonic microparticle impact experiments, the mechanical properties and protective performance of the CoCrNi MEA coating were characterized and compared with those of the aluminum and copper coating. The results show that the CoCrNi MEA coating exhibits a high hardness of 9.7 GPa and an elastic modulus of 146.8 GPa. Under the supersonic impact, the CoCrNi MEA coating shows high coefficient of restitution, low rebound-to-fracture transition velocity, and small impact-mode ratios. The impact-mode ratios of the CoCrNi MEA coating subjected to microparticles of different materials further indicate that the CoCrNi MEA coating can efficiently withstand the high-velocity impact of most metallic particles except tungsten ones. Our work provides direct experimental insights into the excellent impact resistance of CoCrNi MEA coatings, which holds a great promise for improving the reliability and durability of equipment subjected to high-speed collisions of solid particles entrained within the air such as ice and sand dust.

Effects of PVD deposition method on electrochemical properties and interfacial contact resistance of CrN coated titanium as PEMFC bipolar plate

ABSTRACT In this research, CrN coating was applied to grade 1 titanium as a bipolar plate for PEMFC. The CrN was deposited by ion beam assisted deposition (IBAD) and the arc ion plating method (AIP). The thickness of the coating layer was about 2.5∼3 μm and it was densely deposited on the titanium substrate. The electrochemical experiments were conducted in an aqueous solution of pH 3 (H2SO4 + 0.1 ppm HF, 80°C) determined by DoE. Hydrogen gas and air were bubbled to simulate the anode and cathode environments, respectively. Various analyses (XRD, EDS, FE-SEM), electrochemical experiments (EIS, potentiodynamic polarisation, potentiostatic experiment), and interfacial contact resistance measurement were performed to evaluate the effects of the PVD deposition method. Due to the difference in the PVD method, CrN and Cr2N were formed in the IBAD specimen, whereas CrN phase was observed in the AIP specimen. The CrN coated specimens presented improved interfacial contact resistance compared to the titanium substrate.

Optical Interference Filters Combined with Thin Film Residual Stress Compensation for Image Contrast Enhancement

We propose two single-wavelength notch filters and one dual-wavelength (480 and 620 nm) notch filter to enhance image contrast. The stack structure of the notch filters was designed as (Ta2O5/SiO2)4Ta2O5 in Essential Macleod thin film simulation software. Dual-electron-beam evaporation with ion beam-assisted deposition was used to prepare optical interference filters with different center wavelengths. A multilayer notch filter with a center wavelength of 620 nm was deposited on the front surface of the glass, and then a notch filter with a center wavelength of 480 nm was coated on the rear surface of the same glass. The proposed dual-wavelength (480 and 620 nm) notch filter is a combination of two single-wavelength notch filters coated on a double-sided glass substrate to compensate for residual stress. The transmittance, residual stress, and surface roughness of the proposed notch filter were evaluated using different measuring instruments. The experimental results show that the residual stress of the dual-wavelength notch filter could be reduced to 10.8 MPa by using a double-sided coating technique. The root-mean-square (RMS) surface roughness of the notch filters was measured by using a Linnik microscopic interferometer. The RMS surface roughness was 1.80 for the 620 nm notch filter and 2.09 for the 480 nm notch filter. The image contrast obtained with the three different notch filters was measured using an optical microscope and a CMOS camera. The contrast value could be increased from 0.328 (without a filter) to 0.696 (dual-wavelength notch filter).

The Effects of Hemisphere Dome Orientation on the Structure of Diamond-like Carbon Film Prepared Using Ion Beam Assisted Deposition

Diamond-like carbon (DLC) has attracted significant attention in the recent decades because of its unique properties and applications. Ion beam assisted deposition (IBAD) has been widely established in industry due to the advantages of easy handling and scalability. In this work, a hemisphere dome model is specially designed as a substrate. The influence of the surface orientation on the coating thickness, Raman ID/IG ratio, surface roughness and the stress of the DLC films are examined. The reduction in the stress in the DLC films reflects the lower energy-dependence in diamond due to the varied sp3/sp2 fraction and columnar growth pattern. The variation of the surface orientation provides an efficient means of tailoring the properties and microstructure of the DLC films.

Effect of Silver Doping on the Superconducting and Structural Properties of YBCO Films Grown by PLD on Different Templates.

We report the local structural and superconducting properties of undoped and Ag-doped YBa2Cu3O6+x (YBCO) films with a thickness of up to 1 µm prepared by pulsed laser deposition on SrTiO3 (STO) single crystals and on ion-beam-assisted deposition (IBAD) and rolling-assisted biaxially textured substrate (RABiTS)-based metal templates. X-ray diffraction demonstrates the high crystalline quality of the films on both single crystalline substrates and metal-based templates, respectively. Although there was only a slight decrease in Tc of up to 1.5 K for the Ag-doped YBCO films on all substrates, we found significant changes in their transport characteristics. The effect of the silver doping mainly depended on the concentration of silver, the type of substrate, and the temperature and magnetic field. In general, the greatest improvement in Jc over a wide range of magnetic fields and temperatures was observed for the 5%Ag-doped YBCO films on STO substrates, showing a significant increase compared to undoped films. Furthermore, a slight Jc improvement was observed for the 2%Ag-doped YBCO films on the RABiTS templates at temperatures below 65 K, whereas Jc decreased for the Ag-doped films on IBAD-MgO-based templates compared to undoped YBCO films. Using detailed electron microscopy studies, small changes in the local microstructure of the Ag-doped YBCO films were revealed; however, no clear correlation was found with the transport properties of the films.