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Binary ZrCu nanocomposite amorphous films are synthetized by pulsed laser deposition (PLD) under vacuum (2 x 10-3 Pa) and 10 Pa He pressure, leading to fully amorphous compact and nanogranular morphologies, respectively. Then, post-thermal annealing treatments are carried out to explore thermal stability and crystallization phenomena together with the evolution of mechanical properties. Compact films exhibit larger thermal stability with partial crystallization phenomena starting at 420 °C, still to be completed at 550 °C, while nanogranular films exhibit early-stage crystallization at 300 °C and completed at 485 °C. The microstructural differences are related to a distinct evolution of mechanical properties and residual stress, with compact TFMGs showing the highest values of Young’s modulus (157 GPa), hardness (12 GPa), strain rate sensitivity (0.096), and local residual stress (+691 MPa) upon annealing at 550 °C, while nanogranular films reach the maximum values of mechanical properties at 485 °C followed by relaxation at higher temperatures due to complete crystallization. We show that PLD in combination with post-thermal annealing can generate different families of amorphous films with varying nanoscale morphologies, resulting in tunable mechanical properties and thermal stability, which can thus be used for designing novel film configurations for different fields of application.

Photomechanical behaviors of the films of 4-[bis(9,9-dimethylfluoren-2-yl)amino]-4'-cyanoazobenzene (CN-BF1AB) and 4-[bis(9,9-dimethylfluoren-2-yl)amino]-4'-nitroazobenzene (NO2-BF1AB) fabricated on the surface of agar gel have been investigated. Two-stage process including striped pattern formation and the subsequent band-like structure formation was observed upon irradiation with a linearly polarized laser beam with 488 nm, being similar to the result for the film of the parent compound, 4-[bis(9,9-dimethylfluoren-2-yl)amino]azobenzene (BF1AB). The rate of such structural change for CN-BF1AB was almost similar to or somewhat slower than that for BF1AB film. On the other hand, the rate for NO2-BF1AB was considerably slower than those for BF1AB and CN-BF1AB. The results suggested that the photochromic reactivity of the molecule in the amorphous film plays a role for the present photomechanical behaviors.

We report on the effect of carbon ion-implantation on the critical behavior of Fe93Zr7 amorphous films. Both the as-grown and carbon-implanted Fe93Zr7 samples exhibit a second order ferromagnetic to paramagnetic transition. The critical exponents were investigated through different techniques such as modified-Arrott plot, the critical isotherm analysis and the Windom scaling relation. Analysis of the critical behavior was presented in terms of the magnetocaloric effect around TC. While there is a significant increase of the magnetization and TC upon C-implantation, the critical exponents were only slightly affected by implantation and were in line with those of the 3D-Heisenberg model.

In this paper starting from a short review we present our in situ TEM studies of thinfilm transformations initiated by electron beam primarily for initially amorphous layers of several oxides and chalcogen-based materials.

Photomechanical behaviors of the films of 4-[bis(9,9-dimethylfluoren-2-yl)amino]-4'-cyanoazobenzene (CN-BF1AB) and 4-[bis(9,9-dimethylfluoren-2-yl)amino]-4'-nitroazobenzene (NO2-BF1AB) fabricated on the surface of agar gel have been investigated. Two-stage process including striped pattern formation and the subsequent band-like structure formation was observed upon irradiation with a linearly polarized laser beam with 488 nm, being similar to the result for the film of the parent compound, 4-[bis(9,9-dimethylfluoren-2-yl)amino]azobenzene (BF1AB). The rate of such structural change for CN-BF1AB was almost similar to or somewhat slower than that for BF1AB film. On the other hand, the rate for NO2-BF1AB was considerably slower than those for BF1AB and CN-BF1AB. The results suggested that the photochromic reactivity of the molecule in the amorphous film plays a role for the present photomechanical behaviors.

Наведено результати досліджень температурних залежностей електричного опору R та оптичного пропускання θ аморфних плівок SbxTe100-x. Встановлено, що кристалізація плівок супроводжується різким зменшенням R і θ. Параметри переходу «аморфна фаза → кристалічна фаза» залежать від хімічного складу плівок та швидкості нагрівання., Purpose: Thin films of Ge and Sb chalcogenides are suitable for creation of PCM devices that works on the basis of reversible “amorphous phase ↔ crystalline phase” transition. In this paper the results of the investigations temperature dependences electric resistance R and optical transmission θ of SbxTe100-x amorphous films are reported.Methods: Nonisotermal crystallization of SbxTe100-x films was investigated by the method, which allows simultaneously measurements of optical transmission and electric resistance on the one samples. Investigations of R(T) and Q(T) dependences were carried out in the temperature range of 290-550 K. Heating rates were equal 0.75, 1.8 and 4.5 K/min.Results and discussion: It was established that crystallization of films is accompanied by a sharp decrease of R and θ. The change of resistance rich of 3-4 orders higher of magnitude. Parameters of phase transition (the starting temperature from amorphous to crystalline state and temperature range of transition) depends on the chemical composition of the films and the heating rate. The results testifies about possibility to use the films of Sb-Te system for memory cells and temperature sensors production., Приведены результаты исследований температурных зависимостей электрического сопротивления R и оптического пропускания θ аморфных пленок SbxTe100-x. Установлено, что кристаллизация пленок сопровождается резким уменьшением R и θ . Параметры перехода «аморфная фаза → кристаллическая фаза» зависят от химического состава пленок и скорости их нагревания.

The optical transmission spectra of amorphous As40-xSbxS60 films with small antimony content (x=0, 0.8, 1.6, 4, 6) prepared by the thermal evaporation of glasses of corresponding compositions have been measured over the whole 400-750 nm spectral range. It is established that the laser irradiation and annealing of films leads to an absorption edge shift into the long-wave spectral region. The values of pseudoforbidden gap width Eg and refractive index n of films have been determined. The parameters of a single-oscillator model (oscillator energy E0, dispersion energy Ed, and effective coordination number per cation Nc) for the studied films are estimated. The maximum changes in optical characteristics are found for As36Sb4S60 films. Changes in the optical parameters of films are caused by structural transformations taking place in them under the irradiation and annealing., В спектральной области 400-750 нм исследованы спектры пропускания аморфных пленок As40-xSbxS60 с небольшим содержанием сурмы (x=0, 0.8, 1.6, 4.6) полученных термическим испарением стекол соответствующих составов. Установлено, что лазерное облучение и отжиг пленок приводит к сдвигу края поглощения в длинноволновую область спектра. Определены значения ширины псевдозапрещенной зоны Ed и показателя преломления n пленок. Рассчитаны параметры одноосциляторной модели (энергия осциллятора E0, дисперсионная энергия Ed и эффективное координационное число). Максимальные изменения оптических характеристик наблюдались в пленках As36Sb4S60. Изменения оптических параметров пленок обусловлены структурними превращениями, происходящими в них при облучении и отжиге., В спектральній області 400-750 нм досліджені спектри пропускання аморфних плівок As40-xSbxS60 з малим вмістом Sb (х=0, 0.8, 1.6, 4, 6), одержаних методом термічного випаровування стекол відповідних складів на скляні підкладки. Встановлено, що лазерне опромінення та відпал плівок призводять до зсуву краю поглинання в довгохвильову ділянку спектру. Визначені ширина псевдозабороненої зони Egта показник заломлення n плівок. Розраховані параметри одноосциляторної моделі (енергія осцилятора E0, дисперсійна енергія Edта ефективне координаційне число Nc). Максимальні зміни оптичних характеристик виявлені для плівки As36Sb4S60. Зміни оптичних параметрів плівок відбуваються в них при опроміненні та відпалі.

For a high magnetic refrigeration efficiency, a large change of magnetic entropy (-Delta S-M) associated with a high relative cooling power (RCP) are highly desirable. Here, the ion implantation is used to enhance both parameters in FeZr amorphous films. A considerable enhancement of both (-Delta S-M) and RCP, from 0.66 to 1.01 J/kg K and 84.5 to 155.5 J/kg respectively, for the as-grown sample compared to the C -implanted sample is obtained for a magnetic field change of mu(0)Delta H = 1.5 T. The increase of (-Delta S-M) and RCP values, are attributed to the increase of the magnetization and the chemical inhomogeneity, respectively upon C implantation.

Although inorganic crystalline phosphors can exhibit high quantum efficiency, their use in phosphor films has been limited by a reliance on organic binders that have poor durability when exposed to high-power and/or high excitation energy light sources. To address this problem, Sn(2+)-doped transparent phosphate films measuring several micrometers in thickness have been successfully prepared through heat treatment and a subsequent single dip-coating process. The resulting monolithic inorganic amorphous film exhibited an internal quantum efficiency of over 60% and can potentially utilize transmitted light. Analysis of the film's emissivity revealed that its color can be tuned by changing the amount of Mn and Sn added to influence the energy transfer from Sn(2+) to Mn(2+). It is therefore concluded that amorphous films containing such emission centers can provide a novel and viable alternative to conventional amorphous films containing crystalline phosphors in light-emitting devices.

Coordination chem. of natural polyphenols and transition metals allows rapid self-assembly of conformal coatings on diverse substrates. Herein, we report that this coordination-driven self-assembly process applies to simple phenolic mols. with monotopic or ditopic chelating sites (as opposed to macromol., multitopic polyphenols), leading to surface-confined amorphous films upon metal coordination. Films fabricated from gallic acid, pyrogallol, and pyrocatechol, which are the major monomeric building blocks of polyphenols, have been studied in detail. Pyrocatechol, with one vicinal diol group (i.e., bidentate), has been obsd. to be the limiting case for such assembly. This study expands the toolbox of available phenolic ligands for the formation of surface-confined amorphous films, which may find application in catalysis, energy, optoelectronics, and the biomedical sciences. [on SciFinder(R)]

type:Journal Article, Co-Fe-Si-B films have been prepared using a roll coater and DC magnetron sputtering system onto a polyethylene terephthalate substrate. This thin film exhibited an excellent uniaxial anisotropy introduced by an asymmetric thermal shrinkage of the substrate. Reversal with a single layer Barkhausen pulse has been observed in a thin film structure 1mm by 50mm by 0.65 mu m. Closure domains have been clearly identified at the film ends. The threshold for the reversal is the coercive force. The reason for reversal with a single Barkhausen jump is that the long narrow film geometry has essentially zero demagnetizing field over most of the film. Once the walls start to move through the center portion of the film, there is nothing to stop them so the reversal proceeds with a single large Barkhausen pulse.

Представлено результати досліджень нанотвердості аморфних плівок Ge40Se60 при опроміненні лазерним променем з довжиною хвилі 655 нм. Виявлено експоненційне зменшення нанотвердості плівки Ge40Se60 під час лазерного опромінення та аналогічне зростання нанотвердості до початкового значення після припинення опромінювання. Знайдені числові значення релаксаційних параметрів фотоіндукованих змін нанотвердості. Показана кореляція динаміки фотоіндукованих змін нанотвердості з аналогічним процесом, виявленим при дослідженні “in situ” змін мікротвердості плівки Ge40Se60 при аналогічних умовах експерименту. Отримані результати пояснені у рамках інтрамолекулярної моделі фотоіндукованої пластичності., Представлены результаты исследований нанотвердости аморфних пленок Ge40Se60 при облучении лазерным лучем с длиной волны 655 нм. Обнаружено экспоненциальное уменьшение нанотвердості пленки Ge40Se60 во время лазерного облучения и аналогичный рост нанотвердости до начального значения после прекращения облучения. Найдены численные значения релаксационных параметровфотоиндуцированных изменений нанотвердости. Показана корелляция динамики фотоиндуцированных изменений нанотвердости с аналогичным процессом, обнаруженным при исследовании “in situ” изменений микротвердости пленки Ge40Se60 при аналогичных условиях эксперимента. Дано объяснение полученных результатов в рамках интрамолекулярной модели фотоиндуцированнойпластичности., The results of research nanohardness of amorphous films Ge40Se60 irradiated with a laser beam with a wavelength of 655 nm. The exponential nanohardness decrease of Ge40Se60 film during laser irradiation and nanohardness increase, similar to the original value after termination of exposure, were found. The numerical value of relaxation options for photoinduced changes of nanohardness was found. The correlation dynamics of photoinduced changes of nanohardness for the same process, which was identified in the study "in situ" changes of microhardness of Ge40Se60 film, was showed under similarexperimental conditions. The results are explained under the intramolecular photoinduced plasticity model.

The investigation results of (As2S3)100-х(SbSI)х amorphous films transmission spectra depending on exposition conditions are given. It was established that laser illumination of (λ=530 nm) films leads to the absorption edge shift into the longwave spectrum region. The values of pseudo-gap width Eg and refractive index n are determined. It’s been shown that Eg decreases, and n increases with irradiation time growing. Changes of optical characteristics in films are caused by structural transformations taking place in them under laser radiation., Приведены результаты исследований спектров пропускания аморфных пленок (As2S3)100-х(SbSI)х в зависимости от условий экспонирования. Установлено, что лазерное облучение (λ=530 нм) пленок приводит к сдвигу края поглощения в длинноволновую область спектра. Определены значения ширины псевдозапрещенной зоны Eg и показателя преломления п пленок. Показано, что с увеличением времени облучения Eg уменьшается, а п – возрастает. Изменения оптических характеристик пленок обусловле­ны структурными превращениями, происходящими в них под действием лазерного излучения., Приведені результати досліджень спектрів пропускання аморфних плівок (As2S3)100-x(SbSI)x у залежності від умов експонування. Встановлено, що лазерне опро­мі­нення плівок (λ=530 нм) призводить до зсуву краю поглинання у довгохвильову область спектру. Визначені значення ширини псевдозабороненої зони Eg та показника заломлення n плівок. Показано, що з ростом часу опромінення Eg зменшується, а n – зростає. Зміни оптичних характеристик плівок обумовлені структурними перетворення­ми, які проходять в них під дією лазерного випромінювання.

We report on magnetoresistance measurements in SmCo5 amorphous films with a giant imprinted magnetic anisotropy. At low applied field parallel to the easy axis, the magnetoresistance exhibits a hysteretic, square, and antisymmetric shape. The antisymmetry in the magnetoresistance is a result of the non-uniform distribution of the magnetization direction over the sample in conjunction with the extraordinary Hall effect. Moreover, the combination of anisotropic magnetoresistance measurements and magnetic domain imaging demonstrates that the symmetry depends on the magnetization orientation with respect to the applied field.

Приведено результати досліджень ізо- та неізотермічної кристалізації аморфних плівок Sb2Se3 оптичним методом. Показано, що з ростом швидкості нагрівання температура фазового переходу з аморфного стану в кристалічний зсувається в ділянку вищих температур. Визначені кінетичні параметри та запропоновано механізм криста­лізації плівок., The results of isothermal and nonisothermal crystallization investigations of Sb2Se3 amorphous films by optical method are given. It is shown that the increase of the heating rate leads to a shift of the phase transition temperature with amorphous state in to crystalline in the high temperature region. The kinetic parameters of the films crystallization determined and its mechanism is presented., Приведены результаты исследований изо- и неизотермической кристаллизации аморфных пленок Sb2Se3 оптическим методом. Показано, что с ростом скорости нагревания температура фазового перехода с аморфного состояния в кристаллическое сдвигается в область более высоких температур. Определены кинетические параметры и предложен механизм кристаллиза­ции пленок.

The structure of chalcogenide semiconductors amorphous films on all system Ge-Sb-Se was investigated by electron diffraction method. The basic types of the short range order of the disorder network, realized in the amorphous films the given system are certain. Models of structure of amorphous condensates of system Ge-Sb-Se in various concentration areas are offered., Приведены экспериментальные результаты электронографических исследований структуры атомной сетки аморфных пленок системы Ge-Sb-Se с химическими составами, размещенными по всему треугольнику Гиббса. Установлены основные типы ближнего и промежуточного порядка, которые реализуются в таких конденсатах. Предложены модели атомной структуры аморфных пленок с разными типами ближнего порядка., Приведені експериментальні результати електронографічних досліджень структури атомної сітки аморфних плівок системи Ge-Sb-Se з хімічними складами, розміщеними по всьому трикутнику Гібса. Встановлені основні типи ближнього та проміжного порядку, які реалізуються в таких конденсатах та запропоновані моделі їх атомної структури.

The thickness dependence of magnetic properties has been studied in SmCo5 amorphous films with imprinted in-plane anisotropy for thicknesses ranging down to the nanometer scale (2.5-100 nm). The field induced in-plane magnetic anisotropy decreases considerably when the film thickness is below 20 nm. Analysis of the magnetic anisotropy energy shows that the decrease of the induced in-plane anisotropy is accompanied by the development of an out-of-plane interface anisotropy. Two different regimes for the coercivity (H-c) change are found: below 3.75 nm, the H-c decreases continuously with decrease of the film thickness, whereas at above 3.75 nm, the H-c decreases with increase of the film thickness. This change in Hc can be understood by considering the decrease of the short range chemical order for the thinnest films (<3.75 nm) and the relative decrease of the interface contribution with increasing film thickness. The changes in anisotropy have a profound influence on the domain structure, in which the angle of the zigzag domain boundaries decreases with the inverse thickness of the layers.

We show that Sm10Co90 amorphous films exhibit anisotropic magnetostriction effects when a magnetic field is applied perpendicular to the imprinted easy axis of magnetization. At low applied fields (0-100 mT), we observe strong anisotropy in the field response. Parallel to the applied field, the strain scales linearly with the applied field while the strain perpendicular to the field direction ( easy axis) is close to the detection limit. This behavior is accompanied by zigzag domain wall motion with the corners pointing along the easy axis. The origin of the anisotropic magnetostriction is discussed.

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.

The nanolayered structure of a forced-assembly of two immiscible amorphous polymers, prepared by layer-multiplying coextrusion, is analyzed for the first time by means of USAXS. The experimental long spacings for the series of PMMA/PS films studied show a good correlation with the nominal periodicity values of the stacks. In addition, the long spacings, derived from a localized area in AFM, are also in good agreement with the USAXS values averaged over much larger areas. The structural variation, after thermal treatment, of two samples with nominal periodicities of 174 and 215 nm is reported. In the range RT-140 °C, the nanolayered structure is mostly well preserved as evidenced by AFM. However, the absence of USAXS maxima after annealing at temperatures included in the above range has been tentatively explained by interfacial coarsening and spinodal dewetting occurring between the forced-assembled polymer layers. Above 140 °C, the interfacially driven break-up of the layers ends up with the final disappearance of the multilayered structure. © 2010 Elsevier Ltd. All rights reserved.

Atomic force microscopy (AFM) and atomic force acoustic microscopy (AFAM) is used for examination of the role of annealing and illumination of flexible network of Ge0.12As0.17S0.71 amorphous film and rigid network of Ge0.25As0.30S0.45 amorphous film. The virgin state of both films appears to be smooth with the value of smoothness Sa at around 0.8 nm. Annealing leads to changes in topological smoothness (Sa increased up to 5nm in case of S-rich film) attributed to a nano/meso phase separation associated, most probably, with sulfur aggregation in the case of Ge0.12As0.17S0.71 and arsenic aggregation in the case of Ge0.25As0.30S0.45 amorphous film. Illumination of virgin Ge0.12As0.17S0.71 amorphous film leads to less pronounced but similar results as obtained by annealing, while rigid Ge0.25As0.30S0.45 amorphous film is insensitive to used illumination.

Byl syntetizován objemový vzorek As33S67 a rozpuštěn v n-butylaminu. Dále byl v n-butylaminu rozpuštěn AgCN. Po smíchání obou roztoků byly metodou spincoating připraveny tenké vrstvy AgAsS2. Vzorky byly analyzovány EDX metodou, Ramanovou a infračervenou spektroskopií, RBS, XRF, MDSC, UVIS a VASE spektroskopií. Do vrstvy byla exponována holografická mřížka, jejíž parametry byly zjišťovány AFM spektroskopií., Dokončená práce s úspěšnou obhajobou

Byly připraveny objemové vzorky skel ze systémů Sb-S a Ag-Sb-S, z nichž byly metodami vakuového napařování a spincoating, kombinovanými s opticky indukovaným rozpouštěním a difuzí Ag, a metodou laserové ablace připraveny tenké amorfní vrstvy Ag-Sb-S. Tyto vrstvy byly charakterizovány analytickými metodami., Dokončená práce s úspěšnou obhajobou

Ve vysoké čistotě byla připravena skla a tenké vrstvy systému SexS100-x, byla určována jejich struktura Ramanovou spektroskopií. Byly studovány optické vlastnosti skel i vrstev včetně spektrální závislosti indexu lomu a fotoindukované změny vlastností, struktury a byla pozorována opticky indukovaná krystalizace., Dokončená práce s úspěšnou obhajobou

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1997., Vita., Includes bibliographical references., by Harold D. Ackler., Ph.D.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1997., Vita., Includes bibliographical references., by Harold D. Ackler., Ph.D.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1997., Vita., Includes bibliographical references., by Harold D. Ackler., Ph.D.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1997., Vita., Includes bibliographical references., by Harold D. Ackler., Ph.D.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1997., Vita., Includes bibliographical references., by Harold D. Ackler., Ph.D.

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.

The magnetic anisotropy in amorphous soft magnetic CoFeSiB films is modified by He-ion irradiation. A rotation of uniaxial anisotropy depending on the applied field direction in the irradiated areas is observed by magnetometry and complementary domain observation by Kerr microscopy. No significant degradation in magnetic properties relative to the as-deposited state is found from the magnetization loops on non-patterned films. Using irradiation together with photolithography the films were treated locally, resulting in ‘anisotropy patterned’ structures. Complicated periodic domain patterns form due to the locally varying anisotropy distribution. Overall magnetic properties and domain patterns can be adjusted.

The magnetic anisotropy in amorphous soft magnetic FeCoSiB films is modified by He-ion irradiation. A realignment of uniaxial anisotropy depending on the applied field direction in the irradiated areas is observed by magnetometry and complementary domain observation by Kerr microscopy. Using irradiation together with photolithography the films were treated locally, resulting in ‘anisotropy patterned’ structures. Complicated periodic domain patterns form due to the confined anisotropy distribution. Overall magnetic properties and domain patterns can be adjusted.

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.

The effect of rare earth (Dy and Sm) and transition metal (Mn) luminescent impurities on the optical properties of As2S3 glass is studied in a wide spectra! region. The Raman, infrared, band-to-band and edge absorption spectroscopies are employed to obtain information about the incorporation of impurity ions in the host glass structure and the corresponding changes in intrinsic optical characteristics. The effects of light-soaking and thermal treatment on the doped As2S3 glasses were examined as well. In the fundamental absorption region a reflectivity maximum at 2.98 eV shows blue (Dy, Sm) or red (Mn) shift depending on the electronegativity of the impurity, in accordance with the corresponding variations of the glass structure. Near the edge absorption the impurity affects strongly the slope and the magnitude of the weak absorption tail. In the wide range of transparency the addition of impurity suppresses several absorption bands indicating the interaction of dopants with the host glass contaminations. Some variations of the characteristic Raman spectra under light exposure and thermal aging of doped glasses were registered. The observed effects of metal dopants on the As2S3 glass are discussed in connection with the expected behavior of the impurities in the glass., Published in Jnl. of Optoelectronics and Advanced Materials, v3 n2, Jun 2001. p443-454 This article is from ADA398590 International Workshop on Amorphous and Nanostructured Chalcogenides 1st, Fundamentals and Applications held in Bucharest, Romania, 25-28 Jun 2001. Part 1

The influence of the stress relaxation state on the crystallization process has been studied in amorphous Sb0.87Ge0.13 films. Relaxed amorphous areas produced by laser irradiation have been crystallized by isothermal annealing during in situ observation in a transmission electron microscope. The results show that the relaxed material crystallizes at a lower temperature than the as-grown material, and has a higher crystal growth velocity and a lower activation energy for crystal growth. The differences in the crystallization kinetics are in the nucleation process rather than in the growth process.

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Amorphous Tb/Co compositionally modulated films were deposited on Si substrates with different modulation layer thicknesses ranging from about 2.5 to 15 Å. The nominal Tb to Co layer thickness ratios were systematically varied and the complex refractive index (n and k) and polar magneto-optical Kerr effects (rotation and ellipticity) were measured in the 3000–8000-Å spectral range as well. The samples were divided into two groups. In one group, the thickness of the Co layers was fixed, the Tb layer thickness varied. In the second group, the thickness of the Tb layer was fixed, and that of the Co layer thickness varied. The Kerr rotation and the coercivities of the samples showed very consistent and interesting changes. X-ray diffraction and x-ray fluorescence were also performed on the samples, which revealed layered structures, or compositional modulation, and provided information on the Tb to Co atomic ratios in the samples. Journal of Applied Physics is copyrighted by The American Institute of Physics.

Thin films of substoiciometric silicon nitride were grown by the use of ion beam assisted deposition. The amorphous films were annealed at high temperatures (1017-1200C) to produce crystalline alpha-Si3N4. Both highly symmetric spherulitic crystal morphologies and irregular fractal aggregates were seen. In the latter case, a fractal dimension of 1.2 was measured. These two macroscopically different forms possessed correspondingly different microstructures. The morphologies were found to be determined by the temperature of the anneal., Prepared in collaboration with Illinois Univ., Urbana. Materials Research Lab.

A new interpretation of the anisotropy of the conductivity in thin films of a-Ge, and a-Si is presented. The interpretation is based on a transition, previously proposed by the other author, from percolation conduction to Miller and Abrahams conduction at small film thickness. A simple theory together with experimental data is presented. The comparison between them is found to be good. (Modified author abstract), Prepared in cooperation with the Bell Telephone Labs., Murray Hill, N.J.

A new interpretation of the anisotropy of the conductivity in thin films of a-Ge, and a-Si, reported by one of use (J.J.H.) is presented. The interpretation is based on a transition, previously proposed by the other author, from percolation conduction to Miller and Abrahams conduction at small film thickness. A simple theory together with experimental data is presented. The comparison between them is found to be good. (Author), Prepared in cooperation with Bell Telephone Labs., Murray Hill, N.J.

© 2007 IOP Publishing Ltd. The study was partially supported by the local government (Junta de Castilla y León) under Grant No VA018A06 and by the Spanish TEC2005 under Grant No 05101/MIC. The authors acknowledge CAI de Técnicas Físicas, CAI de Espectroscopía y Espectrometría and CAI de Microscopía y Citometría of the Universidad Complutense de Madrid for technical support. This work was made possible thanks to the AP2003-4434-FPU grant of the SpanishMEC and the contract TEC 2004-1237/MIC of the Spanish MCYT., Thin films of hafnium oxide have been deposited by the high-pressure reactive sputtering (HPRS) system. In this growth system the deposition pressure is around 1 mbar, three orders of magnitude higher than in the conventional ones, assuring that both reflected and sputtered particles reach the substrate with a low energy. The amorphous or polycrystalline structure is modified by adjusting the ratio of oxygen to argon of the sputtering gas. The electrical characteristics of both polycrystalline and amorphous films are compared. In all cases, the leakage current can be fitted to Poole-Frenkel emission. Amorphous films show the best characteristics in terms of capacitance-voltage behaviour, leakage current and interfacial state density, with conductance and flat-band voltage transients almost negligible., Spanish MEC, Spanish MCYT, Depto. de Estructura de la Materia, Física Térmica y Electrónica, Fac. de Ciencias Físicas, TRUE, pub