Superhydrophobicity is obtained on photolithographically structured silicon surfaces consisting of flat-top pillars after a perfluorosilanization treatment. Systematic static contact angle measurements were carried out on these surfaces as a function of pillar parameters that geometrically determine the surface roughness, including pillar height, diameter, top perimeter, overall filling factor, and disposition. In line with thermodynamics models, two regimes of static contact angles are observed varying each parameter independently: the "Cassie" regime, in which the water drop sits suspended on top of the pillars (referred to as composite), corresponding to experimental contact angles greater than 140-150 degrees, and the "Wenzel" regime, in which water completely wets the asperities (referred to as wetted), corresponding to lower experimental contact angles. A transition between the Cassie and Wenzel regimes corresponds to a set of well-defined parameters. By smoothly depositing water drops on the surfaces, this transition is observed for surface parameter values far from the calculated ones for the thermodynamic transition, therefore offering evidence for the existence of metastable composite states. For all studied parameters, the position of the experimental transition correlates well with a rough estimation of the energy barrier to be overcome from a composite metastable state in order to reach the thermodynamically favored Wenzel state. This energy barrier is estimated as the surface energy variation between the Cassie state and the hypothetical composite state with complete filling of the surface asperities by water, keeping the contact angle constant.

An innovative deposition system has been developed to construct complex material thin films from single-element precursors by chemical beam vapor deposition (CBVD). It relies on well distributed punctual sources that emit individually controlled precursor beams toward the substrate under high vacuum conditions combined with well designed cryo-panel surfaces that avoid secondary precursor sources. In this configuration the impinging flows of all precursors can be calculated at any substrate point considering the controlled angular distribution of the emitted beams and the ballistic trajectory of the molecules. The flow simulation is described in details. The major advantage of the deposition system is its ability to switch between several possible controlled combinatorial configurations, in which the substrate is exposed to a wide range of flow compositions from the different precursors, and a uniform configuration, in which the substrate is exposed to a homogeneous flow, even on large substrates, with high precursor use efficiency. Agreement between calculations and depositions carried out in various system configurations and for single, binary, or ternary oxides in mass transfer limited regime confirms that the distribution of incoming precursors on the substrate follows the theoretical models. Additionally, for some selected precursors and in some selected conditions, almost 100% of the precursor impinging on the substrate is incorporated to the deposit. The results of this work confirm the potentialities of CBVD both as a research tool to investigate efficiently deposition processes and as a fabrication tool to deposit on large surfaces.

We have used time-resolved x-ray photoemission electron microscopy to investigate the magnetization dynamics induced by nanosecond current pulses in NiFe/Cu/Co nanostripes. A large tilt of the NiFe magnetization in the direction transverse to the stripe is observed during the pulses. We show that this effect cannot be quantitatively understood from the amplitude of the Oersted field and the shape anisotropy. High-frequency oscillations observed at the onset of the pulses are attributed to precessional motion of the NiFe magnetization about the effective field. We discuss the possible origins of the large magnetization tilt and the potential implications of the static and dynamic effects of the Oersted field on current-induced domain-wall motion in such stripes. The possibility of manipulating the magnetic configuration of nanostructures by using electrical currents is a recent, exciting development in spintronics. Electrical currents can affect the magnetization of magnetic nanostructures through both the charge and the spin of the conduction electrons. In recent years it has been shown that spin-transfer torque (STT) 1,2 and Rashba spin-orbit torque effects 3 act on the magnetization, in addition to the classical Oersted magnetic field H Oe . In general, the combination of these effects should be taken into account in the description of the magnetization dynamics during the application of a current pulse. For instance, it was shown that the contribution of the Oersted field and not only STT is needed to explain the magnetization reversal in trilayered pillars induced by a current flowing perpendicular to the plane of the layers.4,5 For in-plane currents, H Oe has been invoked to explain magnetization reversal in mesoscopic NiFe/Cu/Co/Au bars 6 and the resonant depinning of constricted domain walls (DWs) in NiFe/Cu/Co trilayers. 7Several studies on the effects of current pulses on the magnetization of nanostripes, mainly concerning currentinduced domain-wall motion (CIDM), have been based on the observation of the domain structure before and after the application of a current pulse. 8,9 However, the effect of the Oersted field on the magnetization can only be investigated by direct, dynamic observations during the current pulses. This has been achieved in this work, using time-resolved x-ray magnetic circular dichroism combined with photoemission electron microscopy (XMCD-PEEM). Our results show that the current-induced field during nanosecond pulses causes both quasistatic and precessional effects on the NiFe magnetization. These effects may contribute to the increased efficiency of current-induced domain-wall motion observed in such trilayers. 10-12Stacks of Cu(2 nm)/Ni 80 Fe 20 (5 nm)/Cu(5 nm)/Co(5 nm)/ CoO(6 nm) deposited on highly resistive Si(100) (ρ > 300 cm) were patterned in 400-nm-wide zigzag stripes, with angles of 90• and 13-μm-long straight sections, combining electron-beam lithography and ion-beam etching. Contact electrodes made of Ti/Au were subsequently deposited using evaporation and a lift-off...

Combinatorial high-vacuum chemical vapor deposition (HV-CVD) was used to identify the conditions required to obtain hafnium-doped lithium niobate thin films on sapphire {001} substrates. Niobium tetraethoxydimethylaminoethoxide (Nb(OEt) 4 (dmae)), lithium tert-butoxide (Li(OBu t )), and hafnium tert-butoxide (Hf(OBu t ) 4 ) were used as precursors. X-ray diffraction (XRD) and transmission electron microscopy (TEM) indicated that a single phase of textured {001} Hf-doped lithium niobate film was obtained under certain precursor flux conditions. The lithium content ()) of the textured film was estimated using Raman spectroscopy to be about 49 mol %. The presence of hafnium inside the films was confirmed by X-ray photoelectron spectroscopy (XPS) measurements, and the hafnium content of the textured film ([Hf]/([Hf] þ [Nb])) was estimated to be about 3 mol %. XPS data confirmed that Hf and Nb, respectively, are in the þ4 and þ5 oxidation states inside the film. The film consists of nearly parallel {001} hafnium-doped lithium niobate columns with different in-plane orientations.