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The European Synchrotron and free-electron laser User Organisation (ESUO) represents about 22.000 users from 30 European member states and associated countries. Each country is represented within ESUO by one up to four national delegate(s), depending on the size of the user community in the respective country. The ESUO aims and activities are shown in this poster.

The European Synchrotron and free-electron laser User Organisation (ESUO) established in 2010 represents about 22.000 users. It is composed of 30 member countries. Our vision is to support a thriving (European) synchrotron and FEL user community with equal opportunities of access and participation for all scientists, based solely on the scientific merit of their ideas.

The European Synchrotron and free-electron laser User Organisation (ESUO) established in 2010 represents about 22.000 users. It is composed of 30 member countries. Our vision is to support a thriving (European) synchrotron and FEL user community with equal opportunities of access and participation for all scientists, based solely on the scientific merit of their ideas.

11th European Symposium on Martensitic Transformations, ESOMAT2018, Metz, France, 27 Aug 2018 - 31 Aug 2018; 2 pp. (2018)., The combined effect of solubilisation, hot deformation and precipitation phenomena affect the mechanical behaviour and functional properties of shape memory alloys (SMA). In order to evaluate the hot workability and processing parameters, in situ deformation experiments were conducted with the high energy X-ray diffraction (HEXRD) setup of the HZG beamline (EH3, P07, Petra III, DESY, Hamburg). The uniaxial compression tests were carried out under controlled atmosphere in a modified dilatometer Bähr DIL 805 A/D with tensile/compressive stress units. Solubilisation temperatures of 800, 850, 900 and 950ºC, followed by 500ºC annealing, combined with compressive deformation, were analysed in order to optimize the processing parameters.

The European Synchrotron and free-electron laser User Organisation (ESUO) established in 2010 today represents about 30.000 users. We aim at representing the users from all European countries. Each country is represented within ESUO by one up to four national delegate(s), depending on the size of the user community in the respective country. The ESUO aims and activities are shown in this poster.

X-ray diffraction using synchrotron radiation was used for real-time investigation of the phase evolution of Ni/Ti multilayer thin films during annealing. These multilayers were deposited onto Tie6Ale4V substrates by dc magnetron sputtering from pure Ni and Ti targets. The deposition parameters were adjusted in order to obtain a near equiatomic chemical composition and modulation periods (L) below 25 nm. Along the entire thickness of the films, well-defined structures with alternate Ni- and Ti-rich layers are observed, even for L ¼ 4 nm. In this case, a halo characteristic of an amorphous structure is obtained, while for L of 12 and 25 nm the as-deposited thin films are nanocrystalline being possible to identify the (111) Ni and (002) Ti diffraction peaks. The nanolayered structure vanishes during annealing due to interdiffusion followed by reaction. The reaction between Ni and Ti to produce NiTi in the cubic B2 structure occurs in a short delay of time and within a narrow temperature range. For L of 25, 12 and 4 nm, the reaction temperature is close to 320, 350 and 385 C, respectively. For higher temperatures, in addition to the austenitic phase, the NiTi2 phase is identified. The diffusion of Ti from the substrate and Ni towards the substrate could favour the precipitation of NiTi2.

Nickel-Titanium (Ni-Ti) thin film shape memory alloys (SMAs) have been widely projected as a novel material, which can be utilized in microdevices. Characterization of their physical properties and its correlation with phase transformations has been a challenging issue. In the present study, X-ray beam diffraction has been utilised to obtain the structural information at different temperatures while cooling. Simultaneously, electrical resistivity (ER) was measured in the phase transformation temperature range. The variation of ER and integral area of the individual diffraction peaks of the different phases as a function of temperature have been compared. A mismatch between the conventional interpretation of ER variation and the results of the XRD data has been clearly identified.

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In-situ X-ray scattering measurements were carried out during Ni-Ti shape memory alloy film processing at the Rossendorf Beamline (BM20-ESRF). The experiments performed with a two-magnetron sputter deposition chamber mounted into the six-circle diffractometer of the beamline enabled us to identify the different steps of the structural evolution during deposition with a set of parameters as well as to evaluate the effect of changing parameters (Ti target power) during film growth. The results show that the type of substrate plays an important role for the preferential orientation of sputtered Ni-Ti films. Amorphous SiO2 and TiN buffer layers were used to successfully control their crystallographic orientations. The deposition conditions leading to films mainly containing grains with (100) or (110) planes of the B2 phase parallel to the film surface are presented. The control of texture is an important achievement since it has a strong influence on the extent of the strain recovery of the Ni-Ti films. The deposition of graded Ni-Ti films by deliberately changing the Ti:Ni ratio, thereby altering microstructure and transformation temperatures across the film thickness, provided significant data for the optimisation of the deposition parameters in order to fabricate films with a “two-way” actuation (films with a combination of superelasticity and shape memory characteristics). This is a plus for the miniaturization of Ni–Ti films based devices in the field of micro-electro-mechanical systems since no consideration has to be paid to a resetting spring.

The study of Ni-Ti shape memory alloy films is of great technological interest for applications in the field of microengineering. They can work as sensors and actuators at the same time. However, there are still important issues unresolved like formation of film texture and its control. Films exhibiting the two-way shape memory effect are also required. A better understanding of the underlying growth mechanisms and their microstructural development requires sophisticated in-situ techniques. A two-magnetron sputter deposition chamber mounted into the six-circle diffractometer of the Rossendorf Beamline at the European Synchrotron Radiation Facility has been used for the processing of the Ni-Ti films. The in-situ x-ray diffraction studies enabled us to identify the different steps of the structural evolution during deposition with a set of parameters as well as to evaluate the effect of changing parameters (Ti target power) during film growth. It has been found that the type of substrate plays an important role for the preferential orientation of sputtered Ni-Ti films. In some cases they exhibit a pronounced depth dependence of their preferential orientations. Amorphous SiO2 and TiN buffer layers have been used to successfully control their crystallographic orientations. This is an important achievement since the texture has a strong influence on the extent of the strain recovery of the Ni-Ti films. The deposition conditions leading to films mainly containing grains with (100) or (110) planes of the B2 phase parallel to the film surface are presented. The deposition of graded Ni-Ti films by changing deliberately the Ti:Ni ratio, thereby altering microstructure and transformation temperatures across the film thickness, has also been performed. The aim has been the optimization of the deposition parameters in order to fabricate films with a “two-way” actuation (films with a combination of superelasticity and shape memory characteristics). It will lead to the development of smaller devices due to an optimal design of microdevices regarding size and weight (i.e., no consideration has to be paid to a resetting spring).

Near equiatomic and Ti-rich Ni–Ti polycrystalline films have been deposited by magnetron co-sputtering using a chamber installed at a synchrotron radiation beamline. The in situ X-ray diffraction studies enabled the identification of different steps of the structural evolution during film processing. The depositions on a 140 nm amorphous SiO2 buffer layer heated at 520°C (without applying bias voltage, Vb, to the substrate) led to a preferential growth of oriented grains of the Ni–Ti B2 phase from the beginning of film growth until the end of the deposition. Films exhibiting a preferential growthof oriented grains of the Ni–Ti B2 phase from the beginning of the deposition were obtained (without and with a Vb of - 45 V) by using a TiN coating with a topmost layer formed by oriented grains. Those trends have been observed for the growth of near equiatomic (~50.0 at.% Ti–Ni) and Ti-rich (~50.8 at.% Ti–Ni) Ni–Ti films. Additionally, an ion gun had been commissioned, which allows ion bombardment during sputter deposition or post-deposition ion irradiation. In this first series of experiments, a Ni–Ti film was irradiated with He ions after deposition (without exposing the film to the atmosphere, i.e., avoiding surface oxide formation), thus modifying deliberately the microstructure of the film locally.

The deposition of Ni-Ti films with definite stoichiometry and high purity remains still a challenge. Furthermore, important issues like the formation of film texture and its control are not yet resolved. Near equiatomic (~ 50.0 at.% Ti¨CNi) and Ti-rich (~ 50.8 at.% Ti¨CNi) Ni-Ti polycrystalline films (thickness values ¡Ü 800 nm) have been deposited by magnetron co-sputtering using a chamber installed into the six-circle diffractometer of the Rossendorf beamline at the European Synchrotron Radiation Facility. The in-situ X-ray diffraction studies enabled the identification of different steps of the structural evolution during films processing. Films exhibiting a (100) preferential orientation for the B2 phase have been successfully produced. A continuous increase of the B2(200) diffraction peak intensity has been observed for depositions on a 140 nm amorphous SiO2 buffer layer heated at 520¡ãC (without substrate bias voltage, Vb). A (100) texture has been observed for films as thick as 800 nm. Films deposited without and with Vb on a TiN coating with a topmost layer formed by oriented grains have shown a preferential growth of oriented grains of the B2 phase from the beginning of the deposition. Those trends have been observed for the growth of near equiatomic and Ti-rich films.

Due to the high sensitivity of Ni–Ti films to environmental changes, e.g. thermal, and/or to stress, they are ideal materials for applications on micro-sensors. It was aimed to obtain Ni–Ti films exhibiting the beginning of the B25R-phase transformation between room temperature (RT) and 0°C. Thus, films with a slightly Ni-rich composition were prepared by sputtering, without intentional heating of the substrate. The Ni–Ti films were deposited on an Si3N4 intermediate layer previously deposited on naturally oxidized Si(100). The crystallization behaviour of the samples (at a constant temperature of 430°C) was studied by X-ray diffraction in grazing incidence geometry off-plane (GIXD) at a synchrotron-radiation beamline. The GIXD patterns obtained during the annealing process of the Ni–Ti polycrystalline films revealed mainly an austenitic structure (B2 phase) and the precipitation of Ni4Ti3. The results have also shown that the presence of an intermediate layer of Si3N4 enhances the crystallization process of the Ni–Ti sputtered films when compared to the films deposited directly on single-crystal Si (with native oxide). The phase transformation behaviour of the Ni–Ti film on Si3N4 was evaluated by XRD in off-plane Bragg–Brentano geometry during cooling (RT-> -40°C) and heating (-40°C ->RT). It has been observed that a high fraction of the Ni–Ti film is already transformed to R-phase at 9°C (austenitic at RT), as well as a very small temperature hysteresis for the B25R-phase transformation. After the characterization described above, the film was removed from the substrate. The free-standing film showed a pronounced ‘‘two-way’’ shape memory effect (SME). In the austenitic state the film presents a flat shape. During cooling, by reducing its distance from ice cubes (i.e., decreasing the surrounding temperature), the film starts bending exhibiting a final curled shape (yet without touching the ice). On heating it recovers its flat shape. The authors attribute the nature of this ‘‘two-way’’ SME to the Ni4Ti3 precipitates that formed during the heat treatment.

Ni-Ti SMA films are attractive materials for microfabrication and integration in micro-miniature systems composed of mechanical elements, actuators, sensors and electronics made on one chip. However, there are still important issues unresolved like formation of film texture and its control as well as substrate effects. It is essential to identify and control their preferential orientation since it is a crucial factor in determining the shape memory behaviour. Widening the scope of previous experiments concerning the influence of the deposition parameters on the Ni-Ti films structure, the incorporation of a TiN intermediate layer was tested. Here, it is established a clear relationship between the TiN substrates and Ni-Ti texture development (B2 phase) and it is shown that the distinct crystallographic orientations of the Ni-Ti films influence their phase transformation behaviour. The influence of a substrate bias voltage on the preferential orientation of the B2 phase and transformation temperatures is as well revealed.

The technological importance of thin films has led to an unabated interest in the detailed characterization of their structure, morphology, and their interfaces. A real understanding of the underlying growth mechanisms and their microstructural development requires sophisticated in situ techniques. X-ray diffraction with high-brilliance beams is such a powerful technique, as it is demonstrated here for the study of Ni-Ti films. Numerous examples of investigations on Ni-Ti films can be found in the literature but it has been reported that the deposition of Ni-Ti films with definite stoichiometry and high purity remains a challenge, and important issues like formation of film texture and its control are still unresolved. It is essential to identify and control their preferential orientation since it is a crucial factor in determining the shape memory behaviour. Widening the scope of our previous experiments concerning the influence of the deposition parameters on the structure of the Ni-Ti films, the incorporation of a TiN buffer layer has been tested. Here, it is established a clear relationship between the TiN substrates and Ni-Ti texture development (B2 phase) and it is shown that the distinct crystallographic orientations of the Ni-Ti films influence their phase transformation behaviour. The influence of a substrate bias voltage on the preferential orientation of the B2 phase and transformation temperatures is as well revealed. A lower biaxial stress state and lower phase transformation temperatures have been observed for the films deposited with bias (-45 and -90V). Therefore, the control of the energy of the bombarding ions could be used as a tool for the manipulation of the transformation temperatures.

The preferential orientation of Ni-Ti thin films is a crucial factor in determining the shape memory behavior. The texture has a strong influence on the extent of the strain recovery. The relationship between structure and deposition parameters is of extreme importance for future device applications. Our approach is in-situ x-ray diffraction during deposition carried out in a process chamber installed at a synchrotron radiation beamline. Near-equiatomic films were co-sputtered from Ni-Ti and Ti targets. Substrate type and bias voltage play an important role for the preferred orientation. On naturally oxidized Si(100) substrates the NiTi B2 phase starts by stacking onto (h00) planes and then changes to (110) fiber texture with increasing film thickness. For thermally oxidized Si(100) substrates, this cross-over is only observed when a bias voltage is applied. The experiments were supplemented by ex-situ transmission electron microscopy and Auger Electron Spectroscopy allowing an additional deeper insight into the film/substrate interface.

Ni-Ti thin films have been recognized as promising and high performance materials in the field of microelectromechanical system applications. However, important issues like formation of film texture and its control are still unresolved. Widening the scope of previous experiments concerning the influence of the deposition parameters on the Ni-Ti films structure, here we show how different crystallographic orientations can be obtained by changing the substrate type. The growth of near-equiatomic Ni-Ti films, deposited by magnetron co-sputtering from Ni-Ti and Ti targets on heated substrates ( 470C), has been studied in situ by x-ray diffraction at a synchrotron radiation beamline. As mentioned in other studies for depositions on Si(100), a (110) fiber texture is observed for the B2 phase. However, a preferential stacking of (100) planes of the B2 phase parallel to the film surface was observed when using a MgO(100) substrate. The preferential orientation of B2(100) // MgO(100) was very strong and was kept as such until the end of the deposition, which lasted for 2 hours (~ 900 nm). Ni-Ti films were also deposited on a TiN layer (~ 15 nm) previously deposited on top of a SiO2/Si(100) substrate. In this case, a crossover from (110) oriented grains dominating at small thicknesses, to (211) oriented grains taking over at larger thicknesses was observed. These are promising results concerning the manipulation of the crystallographic orientations of Ni-Ti thin films, since the texture has a strong influence on the extent of the strain recovery.

Ni-Ti thin films are promising high performance materials in the field of micro-electro-mechanical system (MEMS) applications. Their preferential orientation is a crucial factor in determining the shape memory behavior since it has a strong influence on the extent of the strain recovery. The relationship between structure and deposition parameters is of extreme importance for future device applications. Our approach is in-situ x-ray diffraction during deposition carried out in a process chamber installed at a synchrotron radiation beamline. Near-equiatomic films (800nm) were co-sputtered from Ni-Ti and Ti targets on heated substrates (~470C) without applying a substrate bias voltage. The texture evolution during deposition is clearly affected by the substrate type. On naturally oxidized Si(100) substrates the Ni-Ti B2 phase starts by stacking onto (h00) planes, and, as the thickness increases, evolves to a (110) fiber texture. An initial significant change of the lattice parameter, as calculated from d(200) , is observed and its tendency for stabilization is coincident with the deposition time where the preferential stacking of B2 phase on (110) planes is starting. For the deposition on thermally oxidized Si(100) there is a strong preferential stacking on (h00) planes of B2 leading to a (100) fiber texture. The measured lattice constants do not exhibit such a strong initial variation as for the sample deposited on naturally oxidized Si(100) substrate, but a continuous slight decrease of this value is perceptible. Ni-Ti films were also deposited on top of a TiN buffer layer. There is a preferential growth of oriented grains of the Ni-Ti B2 phase [ grains are defined as grains with a plane from the {hkl} family parallel to the film surface] from the beginning of the deposition, with a constant growth rate during the whole deposition for a Ni-Ti film deposited on TiN with a topmost layer formed mainly by oriented grains. The Ni-Ti films deposited on top of a TiN layer where a dominating orientation could not be identified (primarily and oriented grains nucleate and grow) exhibit a different behavior. In this case oriented grains of the Ni-Ti B2 phase dominate at small thicknesses while oriented grains take over at larger thicknesses. The decrease of the lattice parameter suggests that the films experience compressive stress which is significantly relaxed with increasing film thickness.

A sputter deposition hamber inserted into the six-circle Huber diffractometer of the materials research station of the ROssendorf BeamLine (ROBL-CRG) at ESRF allowed to perform in-situ experiments during film growth of Ni-Ti. It is equipped with Kapton windows for X-Ray Diffraction (XRD) and specular Reflectivity (XRR) measurements. By following in situ the evolution of the structure of the growing film, we reveal intermediate “states” which cannot be seen/revealed ex situ , because those states ocurred only during the growth but were no longer visible after deposition. Vertical Bragg-Brentano large-angle scattering geometry was employed to study the different trends of structural transformations taking place during deposition. Ni-Ti films exhibiting a non-uniform phase content across the film thickness could be produced by varying the power of co-sputtering Ni-Ti plus Ti. A significant decrease of IB2{110}/IB2{200} was observed when a bias of -45 V was applied.

Shape Memory Alloy (SMA) NiTi thin films have attracted much interest as functional and smart materials due to their unique properties. However, there are still important issues unresolved like formation of film texture and its control as well as substrate effects. For microelectromechanical systems (MEMS) integration, there is a need for an electrically and thermally insulating or sacrificial layer like poly-Si. In the present study, NiTi thin films have been prepared by d.c. magnetron sputtering on Si(100) and poly-Si/Si(100) substrates to elucidate the substrate influence on the crystallization of these films. Following the structural development of the films during crystallization (at a constant temperature of 430 ºC) by GIXD, is was observed that the crystallization process is significantly enhanced for low target/substrate distances of 4 cm instead of 7 cm for Si(100) substrates. The presence of an intermediate layer of poly-Si furthermore drastically enhances the crystallization process. In-situ XRD during the growth of Ni-Ti thin films was chosen in order to investigate their texture development using a deposition chamber installed at ROBL. Near-equiatomic films were obtained by co-sputtering from Ni-Ti and Ti targets. The texture evolution during deposition is clearly affected by the substrate type and the ion bombardment of the growing film. On naturally oxidized Si(100) substrates the NiTi B2 phase starts by stacking onto (h00) planes, and as the thickness increases evolves into a (110) fiber texture. This pronounced cross-over is only observed when a substrate bias voltage (-45 V) is applied for the deposition on thermally oxidized Si(100) substrates. The oxide layer plays an important role on the development of the (100) orientation of the B2 phase during deposition on heated substrates (~ 470ºC). The effect of a TiN layer deposited on top of the SiO2/Si(100) substrate prior to the deposition of the NiTi films was also analysed. These experiments have shown that TiN acts not only as a diffusion barrier, but also induces different crystallographic orientations. These are promising results concerning the manipulation of the crystallographic orientations of NiTi thin films, since the texture has a strong influence on the extent of the strain recovery.

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Ni–Ti SMA thin films formed by sputtering have been attracting great interest as powerful actuators in microelectromechanical systems (MEMS) such as micro-valves, micro-fluidic pumps and micro-manipulators. Successful implementation of Ni–Ti micro-actuators requires a good understanding of the relationship among processing, microstructure and properties of Ni–Ti thin films. At the ROssendorf BeamLine (ROBL-CRG) at ESRF, we carried out a series of experiments that clearly illustrate the benefit of in situ studies, not only during annealing, but also during sputtering. The in situ sputtering experiments during film growth were performed using a magnetron sputter deposition chamber installed into the six-circle diffractometer of the materials research station. This facility allowed us to follow, almost in ‘‘real time’’, the structural evolution of the deposited thin films as a consequence of changing deposition parameters.

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NiTi Shape Memory Alloy (SMA) thin films have been recognized as promising materials in the field of microelectromechanical systems (MEMS). Previous studies on the NiTi/Si(100) interface have shown that during high temperature deposition there exist interfacial diffusion and chemical interactions at the interface where Ni and Ti silicides form [1]. Since the NiTi film required for MEMS applications is usually a few micrometers thick, a relatively thin reaction layer could have significant adverse effects on shape memory properties. An intermediate SiO2 layer was found to serve as an effective diffusion barrier but at the expense of film adhesion [2]. For the present study, NiTi thin films were prepared by magnetron co-sputtering from NiTi and Ti targets in a specially designed chamber mounted on the 6-circle goniometer of the ROssendorf BeamLine (ROBL-CRG) at ESRF, Grenoble (France) [3-5]. The depositions were made at a temperature of  470°C on Si(100), Si(111) and poly-Si substrates and a detailed High-Resolution TEM (Philips TEM CM300) analysis of the interfacial structure has been performed. When NiTi is deposited on Si(100) substrate, a considerable diffusion of Ni into the substrate takes place, resulting in the growth of semi-octaeder NiSi2 silicide (Fig. 1). In the case of NiTi deposited on Si(111), there appears an uniform thickness plate, due to the alignment between substrate orientation and the [111]-growth front (Fig. 2). For NiTi deposited on poly-Si, the diffusion is inhomogeneous. Preferential diffusion is found along the columnar grains of poly-Si, which are favorably aligned for Ni diffusion (Fig. 3). These results show that for the NiTi/Si system, the morphology of the diffusion interface is strongly dependent on the type of substrates.

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Shape-memory alloys (SMA) represent a class of metallic materials that has the capability of recovering a previously defined initial shape when subjected to an adequate thermomechanical treatment. Annealing of a Ti-rich Ni–Ti alloy has been followed by in situ high temperature diffraction in order to register the texture as well as the microstrain/microstress evolution. This type of study is relevant to the envisaged applications, because the type of preferential orientation and the corresponding anisotropic response of the material conditions contributes to the success of the SMA application. In the present study we have tested the feasibility of high temperature pole figures determination at ROBL (BM20) at the ESRF, and we have shown that there is a relation between the preferential orientation changing and the structural evolution taking place during annealing.

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