This paper reports on the first realization using high temperature superconductingfilms of the device proposed in 1965 by Giaever: the DC-DC transformer, which involvesflux-flow vortex motion in two superimposed thin films, separated by a thin insulatinglayer. The device was fabricated using the ramp based multilayer technology from anYBa2Cu3O7 based SIS structure grown by pulsed laser deposition. Transportmeasurements exhibiting the coupling and decoupling phenomena between the two vortexarrays are obtained. We discuss the possibility of widening the working range of thisdevice, which constitutes an important result in the effort to use high temperaturesuperconductors for electronics.

Propagation of electromagnetic waves is considered in a crystalline solidmedium with random parameters. We predict the generation of new exciton-typetransversal and longitudinal waves caused by fluctuations of concentration andfrequency.

In future particle accelerators, silicon detectors will be exposed with large doses ofdifferent types of radiation. To understand the corresponding produced damagemechanisms, a systematic study of the influence of the irradiation on the silicon fromwhich the detectors are made has to be carried out. Samples of low n-doped silicon $(n\leq 10^{12}~{\rm cm}^{-3})$ have been irradiated with swift krypton ions $(\langle E\rangle=5.2~{\rm GeV})$ , neutrons from a nuclear reactor $(\langle E\rangle\sim 1~{\rm MeV})$ and energetic electrons $(\langle E\rangle=1.5~{\rm MeV})$ . Resistivity and Hall effect measurements performed after irradiation show that the silicon is changed to a quasi-intrinsic state, characterized by a very highresistivity. The electrically active defects responsible for that evolution are Maynlyacceptor centers, namely divacancy and/or vacancy-doping complexes. Besides, for the highest fluences, only the appearance of a donor center located at about 0.59 eVbelow the conduction band may explain the observed stabilization of the Fermi level at0.61 eV. Finally, using a simulation method, the rates of generation of the different defects are estimated.

A reinvestigation of the phase diagram of the Cu–In–Se system along the quasi-binarycut In2Se3–Cu2Se reveals an existence range of the chalcopyriteα-phase that is much narrower than commonly accepted. The presence of 0.1% ofNa or replacement of In by Ga at the at.% level widens the existence range of theα-phase, towards In- and Ga-rich compositions. We also investigate the interplay between phase segregation and junction formation in polycrystallineCu(In, Ga)Se2 films. Here, we attribute the band bending observed at bare surfacesof the films to a positively charged surface acting as a driving force for theformation of a Cu-poor surface defect layer via Cu-electromigration. Theelectrical properties of this defect layer are different from those found for thebulk β-phase. We suggest that Cu-depletion is self-limited at the observedIn/(In+Cu) surface composition of 0.75 because further Cu-depletion would require astructural transformation. Capacitance measurements reveal two types of junctionmetastabilities: one resulting from local defect relaxation, invoked to explain alight-induced increase of the open-circuit voltage of Cu(In, Ga)Se2 solar cells,and one due to Cu-electromigration.

Thin amorphous CuInS2 films were deposited on the glass substrates by single source thermal evaporation technique. The effect of heat treatments in sulfur atmosphere, in air and under vacuum on the surface layers is discussed in terms of the surface structure of the films. The films were examined by grazing X-ray diffraction and reflectometry (GXRD and GXRR). From a comparison with the GXRD results, the densities of the surface layers are explained by the presence of secondary phases. We established a correlation between stoichiometry and conductivity depending on the annealing conditions.

Metal structures of diffusion limited aggregation type were obtained by controlled electrodifussion in quartz crystal without macroscopic damages. Conditions of temperature, applied voltage and the form, shape and dimension of electrodes were found, in order to obtain fractal branches. Similarity with fractal DLA structures are described and discussed.

It is known that losses of ultra-cold neutrons (UCN) from traps are due to theβ-decay, up scattering and absorption on a surface but we have identified forthe first time a complementary mechanism. We suppose that this arises from an increasein energy of the neutrons resulting in an upper energy spectral cut-off which is abouttwice higher than that for initial stored neutrons. The total probability for such aprocess equals ~10−5 per collision with a trap wall made of stainless steelwithout or with a Fomblin oil and grease coating.

Nd3+-doped KGd(WO4)2 single crystals are investigated as laser mediaand nonlinear Raman shifters. They have been grown by the top nucleated floatingcrystal method. They were Maynly obtained as platelets with two large (010) faces(i.e. perpendicular to the two-fold b'-axis of the monoclinic lattice). Theirspectroscopic properties are given at room and liquid helium temperature:up-conversion fluorescence, absorption from the 4 I 9/2 ground state for an extended Judd-Ofelt parameters analysis, absorption from the 4 F 3/2 excited statenear 1067 nm and Raman spectra have been measured in the direction of the b'-axis intwo orthogonal polarizations.

Silicon-On-Insulator waveguide can be used as photoconductor, the light being coupled in the silicon film by a diffraction grating. Nonlinear effects are induced by the photogeneration of electron-hole pairs. This leads to photocurrent variations which are much faster than in linear regime and also much steeper than the incident light pulse. A model is presented which takes into account the refractive index variations arising from both the excess carrier density and the temperature rise induced by carrier recombination and Joule effect. The photocurrent is calculated for various values of the incident light power, incidence angle and pulse duration.

We describe how a commercial silicon cantilever can be used both as a force probe and a local scatterer of light. This tip can thus be used as the key element of an apertureless Scanning Near-field Optical Microscope (SNOM) combined with an Atomic Force Microscope (AFM). We use a Total Internal Reflection (TIR) illumination to provide a Fresnel evanescent wave with well-defined characteristics. We show how the weak signal issued from the near-field scattered by the tip can be extracted from the background noise. Finally we present how a signal related to the near field can also be obtained when the tip is oscillated at a frequency close to the resonance frequency of the cantilever. These results are compared with a simulation of the lock-in detection. Finally we describe the role of the vibration amplitude on the signal.

By using a simple model based on a linear susceptibility approach and taking into account the dynamic nature of the molecule's electronic structure, the electric fielddiffracted by the near-field probe is evaluated in the presence or absence of a thinsilver layer deposited on the surface of a bulk fluorescent material. This modelingpoints out that the far-field signal emitted by the molecules situated far from thetip is important in the absence of metal coating and can reduce the near-fielddetection sensitivity. It shows that surface metal coating enhances the near-fieldcontribution and decreases the far-field one. Cathodoluminescence images obtained on afluorite (CaF2:Eu) sample confirm the results predicted by modeling.

In this paper, dielectric bi-anisotropic effects on the resonant frequencies of dielectric ring resonators (DRR) are studied in depth. The resulting electromagnetic boundary problem is solved numerically using the mode matching method (MM). In order to validate this numerical model, the obtained results are compared with those of the literature for a uniaxial electric anisotropic dielectric ring resonator.

The electric field measurements in corona discharge provides a complementaryresults for the corona discharge study because the classical theory based on thecurrent and voltage data is unsatisfactory. A new method of current density and fieldmeasurement with a linear biased probe, during the corona discharge, is developed inthis paper. The work has elucidated the phenomenon of probe end-effects using a newprofile of probe adapted to linear geometry. The probe functions were verified and the present theoretical model, which simulates the biased probe by the coplanar planessystem, is thus verified. Other tests have been carried out with a wire-to-planeelectrode system at various parameters. It has been shown that the measured field atthe plane increases linearly with the corona voltage and it decreases as we move awayfrom the centre of plane. The electric field at the plane decreases also as the distancebetween the wire and the plane increases.

From the viewpoint of hard tissue response to implant materials, calcium phosphates are probably the most compatible materials presently known. During the last few years, much attention has been paid to hydroxyapatite and β-tricalcium phosphate as potential biomaterials for bonesubstitute. A good implantation of biomaterials in the skeleton is to reach fullintegration of non-living implant with living bone. The aim of this study is tocompare the resorption kinetics of four kinds of calcium phosphate ceramics:hydroxyapatite (Ca10(PO4)6(OH)2), hydroxyapatite doped with manganese orzinc and a composite material of 75% hydroxyapatite and 25% β-tricalciumphosphate (Ca3(PO4)2). Cylinders (5–6 mm in diameter) of these ceramics werepacked into holes made in the femur diaphysis of mature ovine.At 2, 4, 8, 12, 16, 20, 28, 36 and 48 weeks after the operation, bone/implant interfacewas embedded in polymethylmethacrylate. We used the PIXE method (particle inducedX-ray emission) to measure the distribution of mineral elements (Ca, P, Sr, Zn, Mn andFe) at the bone/implant interface. At 4, 8, 16, 28 and 48 weeks after implantation westudied a biopsy of the ceramics by neutron activation method. Then, we have a globalmeasurement of mineral elements in the biomaterial. The results showed that theresorption kinetics of hydroxyapatite doped with zinc was faster than that of the three other bioceramics.

The improvement of the lateral resolution of 3D atom probe requires the ion trajectories to be determined accurately. For the first time, the atomic structure of the emitter (a sharp tip) and the gradual change of its topology during evaporation are taken into account. Atoms submitted to the highest field are removed one by one. Ion trajectories are then simulated step by step after each atom has been removed from the sample surface. The recurrent use of a simulation software (SIMION 3D) for each elemental step makes it possible to model the image transfer function of 3D atom-probe for a non-stationary shape of the emitter. This dynamic model, applied to atom probe data, is shown to correct for the major aberrations present at the centre of low-index poles. The well-known depleted zone present at the pole centre is shown to disappear using this model. An almost constant density of atoms is then observed over the entire analysis area. For the first time, a physical interpretation of these depleted zones is provided and confirmed through simulation and experiments.