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The control of magnetic properties and anisotropy in ferromagnetic thin films is of importance for many applications in spin electronics. Usually the uniaxial anisotropy in ferromagnetic alloys is set by applying a magnetic in-plane field during thin film deposition or adjusted by magnetic field annealing. In addition to temperature treatment, the alteration of magnetic properties in magnetic thin films by ion irradiation has gained increasing attention in recent years. However, most of the experiments focus on magnetic sandwiches or multilayers, where the magnetic properties depend strongly on the interface structure [1]. Here, we describe how to modify and tune the magnetic anisotropy axis and strength in single layer amorphous FeCoSiB soft magnetic films by ion irradiation with Co- and He-ions locally. Depending on the fluence and field angle during irradiation the uniaxial anisotropy can be realigned in the case of He-ion irradiation [2]. For Cobalt-implantation an increase of uniaxial anisotropy field with increasing fluence by more than a factor of two relative to the as-deposited anisotropy value (from Hk  15 Oe to Hk  40 Oe) is found. The ion treatment is used to “anneal” the films locally and thus to tailor the magnetic properties laterally. Periodic magnetic structures, consisting of regions of alternating anisotropy axis and strength, are generated using photo-lithographic processing. For that reason the films are partially masked with photo resist, patterned by optical lithography, and then irradiated with ions. Depending on the processing conditions and the size of the magnetic patterning, varying from mm in size down to sub-micrometer patterns, different kind of magnetic structures develop. The magnetization is modulated in accordance with the induced lateral anisotropy distribution. However, the domain walls do not align with the boundaries of the structures. Different types of periodic but rather complicated domain patterns are generated under different applied field conditions. The local change of magnetic properties due to the mixed anisotropy is limited by the micromagnetic feature size, not by the structural feature size. By structuring with a feature size smaller than the magnetic length scales, materials with novel magnetic properties are designed. References [1] J. Fassbender, D. Ravelosona, and Y. Samson, J. Phys. D: Appl. Phys. 37, R179 (2004). [2] J. McCord, T. Gemming, L. Schultz, J. Fassbender, M.O. Liedke, M. Frommberger, E. Quandt, Appl. Phys. Lett. 86, 162502 (2005).

The alteration of magnetic properties in magnetic thin films by ion radiation has gained increasing attention in recent years. Here, we present data on the local alteration of the magnetic anisotropy axis in amorphous soft magnetic FeCoBSi films by He-ion irradiation in an applied magnetic in-plane field. Sputtered CoFeSiB (thickness 30 nm) were irradiated with 5 keV He-ions. A magnetic field of 600 Oe was applied during irradiation aligned orthogonal to the initial easy axis of anisotropy. Above a critical fluence an alignment of anisotropy in the applied field direction is observed by MOKE magnetometry and complementary domain observation by Kerr microscopy. Using irradiation together with photolithography the films were irradiated locally, thus resulting in anisotropypatterned structures. Domain patterns in different elements with varying angles of anisotropy and edge orientation, separating regions of different anisotropy alignment, are shown. The influence of the patterning on the (still) full film reversal is discussed in detail.

Six new side-chain polyurethanes with large molecular hyperpolarizabilities were synthesized by reaction of ethylenic and/or azo bridged push-pull chromophoric monomers with tolylene 2,4-diisocyanate. The NLO-phores show different conjugation pathway but analogous donor/withdrawing substituents. The chemical and thermal properties of the chromophores and of the polymers were examined. Evaluation of the second order NLO properties was performed by EFISH determination of mu beta on the monomers, and by SHG measurements on some amorphous thin films obtained from polymers through spin-coating technique. (c) 2004 Elsevier B.V. All rights reserved.

Köçkar, Hakan (Balikesir Author), Production parameters are important for the production of desirable type of magnetic materials. The feasibility of low coercivity amorphous films production using a novel rotating cryostat (RC) technique for sensor application was investigated. Fe81Co13.5Si3.5C2 and Fe67Co18Si1B14 amorphous films was vaporised using a resistively heated furnace on to a liquid nitrogen cooled polyimide Kapton(TM) substrate rotated at the speed of 1300 rpm. The Orthogonal design process was applied in order to systematically optimise the deposition process and parameters over the output functions for the production of low coercivity films. The results indicate that the process can be easily optimised at these level settings with the goal of having the low coercivity amorhous films. By comparing the output function differences with standard deviation for coercivity, the effects of all input parameters (furnace shape, furnace power, mass of material and the gap between substrate and source) on coercivity values of films were analysed. Furthermore, the amorphous nature of these films was confirmed by X-ray measurement.

Bu çalışma, 12-15 Mayıs 2011 tarihleri arasında Antalya[Türkiye]’da düzenlenen 1st International Congress on Advances in Applied Physics and Materials Science (APMAS)'da bildiri olarak sunulmuştur. Fe36Co36B19.2Si4.8Mo2W2 amorphous thin films have been produced by thermionic vacuum arc with thickness varying from 200 nm to 260 mn. X-ray diffraction has been employed to reveal a predominant amorphous phase in the as-prepared samples, although a small crystalline fraction cannot be excluded. The bulk magnetic properties of thin films were examined at room temperature using an ADE Magnetics EV9 vibrating sample magnetometer with maximum magnetic field strength of 1750 kA/m, real-time field control and dynamic gauss range capable of reaching a resolution of 0.08 A/m at low fields. The minimum value of the coercivity for the as-prepared samples was about 7 kA/m. İstanbul Kültür Üniversitesi Gebze Teknoloji Enstitüsü Doğa Nanobiyoteknoloji Terra Labaratuarı Delta Elektrik LOT Oriel Group PHYWE NKUBAP.00.10.YL.10.05

Ga2O3 dielectric thin films were deposited on (111)-oriented p-type silicon wafers by plasma-enhanced atomic layer deposition using trimethylgallium and oxygen plasma. Structural analysis of the Ga 2O3 thin films was carried out using grazing-incidence x-ray diffraction. As-deposited films were amorphous. Upon postdeposition annealing at 700, 800, and 900°C for 30min under N2 ambient, films crystallized into β-form monoclinic structure. Electrical properties of the β-Ga2O3 thin films were then investigated by fabricating and characterizing Al/β-Ga2O3/p-Si metal-oxide-semiconductor capacitors. The effect of postdeposition annealing on the leakage current densities, leakage current conduction mechanisms, dielectric constants, flat-band voltages, reverse breakdown voltages, threshold voltages, and effective oxide charges of the capacitors were presented. The effective oxide charges (Qeff) were calculated from the capacitance-voltage (C-V) curves using the flat-band voltage shift and were found as 2.6×1012, 1.9×1012, and 2.5×10 12 cm-2 for samples annealed at 700, 800, and 900°C, respectively. Effective dielectric constants of the films decreased with increasing annealing temperature. This situation was attributed to the formation of an interfacial SiO2 layer during annealing process. Leakage mechanisms in the regions where current increases gradually with voltage were well fitted by the Schottky emission model for films annealed at 700 and 900°C, and by the Frenkel-Poole emission model for film annealed at 800°C. Leakage current density was found to improve with annealing temperature. β-Ga2O3 thin film annealed at 800°C exhibited the highest reverse breakdown field value. © 2014 American Vacuum Society.

Thin films of Al-W alloys were prepared on sapphire substrates by magnetron co-sputtering. The results of X-ray diffraction analysis proved that the as-prepared samples, within a composition range Al80W20 to Al67W33, were amorphous. The increase of tungsten content in the films (Al60W40 and Al50W50 ) resulted in the appearance in a mixture of two or three metastable crystalline phases. The thermal stability of films was investigated after isochronal annealing the samples for one hour in a temperature range from 293 to 1273 K. It was revealed that there was slight increase in the microhardness during annealing up to a temperature chosen within the interval ~(773-848) K, and such annealing has a small influence on the XRD patterns. In contrast, the annealing above this temperature interval induced detectable changes in the microhardness and significant changes in X-ray diffraction patterns. The results of analysis of XRD patterns demonstrated that amorphous thin films do not disintegrate directly into the ordered equilibrium (a-W, Al4W, and Al5 W) co-existing phases, but the metastable (a-W(Al), b-W(Al), and Al(W)) intermediary phases were observed to appear in the films before the former phases were observed. Thus, for the microhardess behaviour during isochronal annealing of Al-W thin films an explanation given for the metallic glasses investigated earlier can be offered, and this explanation is based also on the results of the XRD investigation we performed. All our microhardness isochronal curves obtained for the both types of annealed samples indicate that mechanisms influencing microhardness change during annealing are similar for amorphous and crystalline states.

Deposition temperature and annealing conditions have pronounced effects on the structure and electrical properties of LPCVD silicon thin films. Films grown at 580 �C are amorphous whereas those grown at 620 �C are microcrystalline. All thin films are subjected to phosphorous diffusion followed by different annealing treatments. Annealing of amorphous films at 1000 �C results in large grains with no favoured orientation and with a relatively high mobility value. Annealing treatment at 1000 �C of the microcrystalline sample results in moderate grain growth with a relatively low mobility which presumably is due to some favoured grain orientation.

DLC films have been coated by PVD on WC-Co substrate with and without Si interface. They have been tested under low (approximately 20%) and high (approximately 80%) humidity conditions by reciprocating friction and wear apparatus. For ascertaining the wear mechanism from the topographies of DLC films, optical and SEM images of wear tracks have been taken. Wear debris particles behave as an abrasive agent, depositing into the film and causing the start of failure. There are multiple wear mechanisms, such as fatigue, abrasion, etc., existing simultaneously in the wear of DLC film in both cases. Wear rate decreases as the total wear way increases. For the case of DLC coating without Si interface there is a good correlation between wear rate and friction coefficient. However, this harmony disappears for DLC/Si coating. A chemically activated process may be assumed as the controlling step in the micro crack propagation during the generation of a wear debris particle. The different tribological behaviors of the DLC coatings under different environmental conditions are explained.

N+ ion beam induced effects on the spin coated amorphous poly(2,6-dimethyl phenylene oxide) (PPO) films in terms of chemical structure and electronic and vibrational properties were investigated using Fourier Transform Infrared spectroscopy (FTIR) and Ultraviolet-Visible (UV-VIS) spectroscopy. Both techniques revealed that the stability of PPO was very weak towards 100 keV N+ ions revealing the threshold fluence to be 1014 ions/cm2 for fragmentation of the polymer. FTIR analysis showed disappearance of all characteristic IR bands at a total fluence of 1014 ions/cm2 except for the band CC at 1608 cm-1 which was found to shift to a lower wave number along with an enhancement in the full width half maximum (FWHM) value with increasing fluence. A new bond appeared due to oxidation as a shoulder at 1680 cm-1 in FTIR spectra indicating the presence of CO type bond as a result of N+ implantation on PPO films. The optical band gap (Eg) deduced from absorption spectra, was observed to decrease from 4.4 to 0.5 eV with fluence. The implantation induced carbonaceous clusters, determined using Robertson's formula for the optical band gap, were found to consist of ~160 fused hexagonal aromatic rings at the maximum energy fluence. An enhanced absorption coefficient as a function of fluence indicated incorporation of either much larger concentration of charge carriers or their mobility than that of the pristine sample. Calculated band tail width from Urbach band tail region for the implanted samples pointed the band edge sharpness to be strongly dependent on fluence indicating an increased disorder with increasing fluence. ? 1999 Elsevier Science B.V.

We report the energetic N+ (100 keV) implantation effect on the spin cast film of poly(2,6-dimethyl phenylene oxide) [PPO] and formation of ion beam induced crystalline nano-clusters, for the first time. Evidence for the formation of highly oriented clusters of ? 22 nm size is obtained from grazing incidence XRD (GIXRD) analysis of the implanted PPO films with a fluence of 6 ? 1016 ions/cm2 whereas the as-deposited film is found amorphous. All the characteristic Raman peaks of PPO film disappears and subsequently a broad peak at 1500 cm-1 in the FT-Raman spectrum appears implying the presence of graphite like carbon (GLC) in the implanted polymer. DC conductivity behaviour in the implanted sample has shown the dominant role of three dimensional (3-D) variable range hopping (VRH) mechanism in the temperature range of 303-500 K. The role of clusters is discussed in analysing the current transport mechanism in the implanted polymer. ? 1999 Elsevier Science B.V. All rights reserved.

Al2O3-TiO2 thin films were prepared by a sol–gel processing. Sols were prepared having different TiO2/Al2O3 molar ratios, i.e., 9:1, 8:2, and 6:4, without and with the addition of 10 at% of K ions. The films were prepared by dipping the substrates (silicon wafers, alkali-free glass or alumina with comb-type Au electrodes) in the sols. The films were fired in air for 1 h at 300, 500, 650 and 800°C. The films were amorphous, at any composition, up to the firing temperature of 500°C. Crystallization of the films was inhibited by larger contents of Al2O3 and K. The humidity-sensitive electrical properties of the thin films were studied using d.c. and a.c. measurements. The addition of K dramatically improved the relative humidity response of the films.

We measure the fluctuations of the vortex-flow voltage in the low-temperature liquid phase of a thick amorphous Mo x Si 1− x film. The anomalous vortex flow with the asymmetric distribution of (real-time) voltage fluctuations is visible in the QVL phase, where we observe noise spectra indicative of shot noise, whose origin is attributed to the vortex bundles that are depinned and pinned randomly in the stationary flow of QVL.

The design of anti-friction coatings able to perform well in different wear conditions without lubricants requires a combination of adequate hardness and toughness, good adhesion, a low friction coefficient and a low wear rate. Recently introduced metal-diamond-like carbon (DLC) coatings can be a major step towards the achievement of such combination. ‘These coatings consist of an amorphous a:CH matrix with the possible incorporation of metal, metal carbide and/or graphite grains. Previous studies of Tix%-DLC coatings deposited on Ti-TiN-TiCN-TiC supporting interlayers showed their good protective properties against abrasive, impact and single scratch wear. Here, ball-on-disk experiments are carried out to investigate these coatings in conditions of sliding wear against steel and WC balls. A comparison of the results for Tix%-DLC and ceramic TiN, TiCN and CrN coatings shows particularly low friction coefficients (below 0.2) and low normalized wear rales for the Tix%-DLC coatings. The results reveal a correlation between the tribological properties of these coatings and the amount of the metal component in their matrix the Ti35%-DLC and Ti20%-DLC are recommended for sliding wear applications. © 1995 Taylor & Francis Group, LLC. 38 829 836 829-836

The recently developed photothermal technique of quadrature photopyroelectric spectroscopy (Q-PPES) has been applied to measurements of amorphous Si thin films deposited on crystalline Si substrates. Direct, meaningful comparisons have been made between purely optical transmission in-phase (IP-PPES) spectra, and purely thermal-wave sub-gap spectra with the use of a novel noncontacting PPES instrument to record lock-in in-phase and quadrature spectra, respectively. FT-IR transmission spectra have also been obtained for a comparison with this IP-PPES optical method. The results of the present work showed that the FT-IR method performs the worst in terms of spectral resolution of thin films and sub-bandgap defect/impurity absorptions inherent in the Si wafer substrate. The optical IP-PPES channel, however, albeit more sensitive than the FT-IR technique, fails to resolve spectra from surface films thinner than 2100 angstrom, but is sensitive to sub-bandgap absorptions. The thermal-wave Q-PPES channel is capable of resolving thin-film spectra well below 500 angstrom thick and exhibits strong signal levels from the crystalline Si sub-bandgap absorptions. Depending on the surface thin-film orientation toward, or away from, the direction of the incident radiation, the estimated minimum mean film thickness resolvable spectroscopically by Q-PPES is either 40 angstrom or 100 angstrom, respectively. 49 6 819 824 Cited By :1

We propose a novel method of oxide crystal growth via atomic-additive mediated amorphization. By utilizing this method, solid-phase crystallization (SPC) of ZnO from amorphous phase has been successfully demonstrated via nitrogen atom mediation. The resultant SPC-ZnO films are highly orientated and the crystallinity is higher than that of the films prepared by conventional sputtering. By using the SPC-ZnO as a buffer layer, the resistivity of ZnO:Al (AZO) films is drastically decreased. 20-nm-thick AZO films with a resistivity of 5 × 10^ Ω cm and an optical transmittance higher than 80% in a wide wavelength range of 400-2500 nm have been obtained.

Micro-Raman spectroscopy measurements were made on polycrystalline and amorphous thin films of CuInTe2 as well as bulk polycrystalline CuInTe2. Various vibrational modes exhibited by the bulk and polycrystalline thin films were attributed to those expected for single crystal CuInTe2. Raman spectra of amorphous films presented a broad spectrum, decomposition of which revealed the presence of elemental tellurium on the film surface. Laser-induced changes on CuInTe2 thin films were studied by acquiring spectra with higher laser beam power. Modes due to tellurium appeared when the spectra were acquired during laser-sample interaction, indicating tellurium segregation. The Raman spectra measured from polycrystalline films during high laser power irradiation did not show decrease in the intensity of the A1 mode of CuInTe2 in spite of loss of tellurium from the lattice. This has been interpreted as related to an increased contribution from the undistorted subsurface CuInTe2 region at higher excitation power. � 2009 IOP Publishing Ltd.

The local setting of magnetic anisotropy by low fluence Co ion implantation in amorphous magnetic thin films is demonstrated. For a wide range of ion fluences no structural changes occur and the adjustment of anisotropy is reversible. A quantitative relationship between the anisotropy change and the atomic displacements is found. Magnetic domain investigations of the purely magnetically patterned stripes reveal an effective quasi-cubic anisotropy below a critical width for orthogonal magnetic anisotropy alignment. The method of ion-annealing allows for a local setting of anisotropy without irreversible structural and magnetic alterations.

Two states of crystallization of silicon can be obtained by cw laser annealing of amorphous material before melting temperature. Comparison between furnace and cw laser annealing of amorphous films give insights about the nucleation and growth process at high temperatures.

In this work, we report the fabrication and characterization of a SiC/SiO2/Si piezoresistive pressure sensor. The sensor structure consists of six PECVD SiC thin-film piezoresistors configured in Wheatstone bridge on a thermally oxidized micromachined silicon diaphragm. In order to fabricate this sensor, three lithographic masks were designed: one to define the square diaphragm (1800 μm×1800 μm), another for the piezoresistors and the third for the Ti/Au metal lines. The diaphragm was formed by anisotropic etching of Si in KOH solution and the piezoresistors by reactive ion etching (RIE) of SiC. The sensor chip size is 4.5 mm×4.5 mm. It was bonded on an alumina substrate using silicone and an aluminum cup was used for protection. The output voltage of the sensor was measured for applied pressure ranging from 0 to 12 psi and voltage suply of 12V.