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The X-ray optical properties of diffraction gratings fabricated on the basis of a Si(400) crystal with a period of D = 1 μm are studied by triple-crystal X-ray diffractometry. The diffraction gratings are manufactured both by silicon profiling during the process of plasma chemical etching and by forming a phase-shift grating on the surface of a Si crystal. The principal difference in the diffraction properties of these gratings is demonstrated. The presence of an Au phase-shift grating is shown to lead to the formation of a two-dimensional diffraction pattern, whereas Si profiling leads to the formation of only a one-dimensional diffraction pattern.

The process of the excitation and propagation of pseudosurface acoustic waves in crystals of the langasite family is studied via X-ray diffractometry for the first time. The investigations are carried out using the BESSY II synchrotron radiation source in the double-crystal X-ray diffractometer scheme. The process of pseudosurface acoustic wave propagation is studied based on an analysis of the diffraction spectra of acoustically modulated crystals. Both the velocities of the pseudosurface acoustic waves and the power flow angles of the acoustic energy are measured for the first time. The pseudosurface acoustic wave is shown to be flowing. Surface and pseudosurface acoustic waves generated by an interdigital transducer in the Z cut of a La3Ga5.5Ta0.5O14 crystal are compared.

A five-component crystal of the lanthanum–gallium silicate family Ca3TaGa3Si2O14 (CTGS) was grown by the Czochralski method. The CTGS crystal, like the langasite crystal (La3Ga5SiO14, LGS), possesses unique temperature properties and the fewer number of the Ga atoms in the unit cell makes the density much lower and, consequently, increases the velocity of acoustic wave propagation. The unit-cell parameters were determined by the powder diffraction technique. The defects in the CTGS crystal structure were studied by X-ray topography, which enables the visualization of growth banding characteristics of crystals grown by the Czochralski method. Surface acoustic wave (SAW) propagation in the CTGS crystal was investigated by the high-resolution X-ray diffraction method on the BESSY II synchrotron radiation source. The velocities of propagation and power flow angles of SAWs in the Y- and X-cuts of the CTGS crystal were determined from the X-ray diffraction spectra.

The transformation of the structure of a radiation-damaged silicon layer and profiles of implanted dopant Zn during thermal annealings has been investigated. The analysis was performed by Rutherford back-scattering spectroscopy, secondary-ion mass spectrometry, and high-resolution X-ray diffraction. It is established that the surface region of radiation-induced point defects (Frenkel pairs) 78 nm thick is formed in the implanted samples. A heat treatment at 400°C leads to the annealing of interstitial point defects and reduces the damaged-layer thickness to 56 nm. This layer may contain vacancy clusters or clusters of zinc-vacancy complexes. The segregation of implanted dopant Zn is observed near the maximum of its depth distribution. Annealing at 700°C leads to the almost complete recovery of the damaged layer. Two concentration peaks were formed in the sample, i.e., one near the substrate surface and the other near the peak of distribution of radiation-induced point defects. During the ion implantation of zinc and at subsequent stages of thermal annealing, zinc precipitated in the form of zinc silicide (of the ZnSiO3 type).

Ca3TaGa3Si2O14 (CTGS) crystals are a new promising material from the lanthanum-gallium silicate family, which can be employed in high-temperature sensors and other acoustoelectronic devices. The structural perfection and acoustic properties of CTGS crystals have been investigated via X-ray topography and diffractometry at the BESSY II synchrotron radiation source in the geometry of a double-crystal X-ray diffractometer.

Ca3NbGa3Si2O14 (CNGS), a five-component crystal of lanthanum-gallium silicate group, was grown by the Czochralski method. The parameters of the elementary unit cell of the crystal were measured by powder diffraction. The independent piezoelectric strain coefficients $$d{}_{11}$$ and $$d_{14}$$ were determined by the triple-axis X-ray diffraction in the Bragg and Laue geometries. Excitation and propagation of surface acoustic waves (SAW) were studied by high-resolution X-ray diffraction at BESSY II synchrotron radiation source. The velocity of SAW propagation and power flow angles in the $$Y$$ -, $$X$$ - and $$yxl/{+}36^\circ$$ -cuts of the CNGS crystal were determined from the analysis of the diffraction spectra. The CNGS crystal was found practically isotropic by its acoustic properties.

A new promising piezoelectric material Ca3TaGa3Si2O14 (CTGS) has been grown using the Czochralski method. Its unit-cell parameters have been determined by means of the X-ray phase analysis method. The X-ray diffractometry method was used to study the crystal acoustic properties; the velocities of surface acoustic wave propagation were measured for the first time and the power flow angles were determined.

The effect of multiple scattering on the formation of the θ-2θ scan curves for a crystal modulated by a surface acoustic wave (SAW), depending on the ultrasonic frequency, has been investigated in the frame-work of the dynamical theory of X-ray diffraction. A model of a Rayleigh surface wave has been analyzed as applied to X-ray diffraction with allowance for the transverse and longitudinal elastic lattice strains. Using the example of the 127° Y′ cut of the LiNbO3 crystal, it is established that the effects of multiple scattering can be neglected for ultrasonic frequencies above 650 MHz; this finding significantly simplifies the numerical calculations of X-ray diffraction from a crystal modulated by a short-wavelength SAW. A comparative quantitative analysis of the experimental data on synchrotron scattering from the 127° Y′ cut of a LiNbO3 crystal modulated by a 952-MHz SAW have been performed, both taking into account and neglecting the effects of multiple scattering. It is shown that the computation time can be reduced by 2 to 3 orders of magnitude.

It is shown that the X-ray beam induced current method (XBIC) can be realized at the laboratory X-ray source using the polycapillary x-ray optics. The images of iron contaminated grain boundaries in multicrystalline Si are obtained. It is shown that the grain boundary XBIC contrast is 2-3 times smaller than the EBIC one. A simulation of XBIC and EBIC contrast values for two-dimensional defects is carried out and a good correlation between the experimental and calculated values is obtained. The dependence of grain boundary XBIC contrast on the X-ray beam width is calculated.

Zinc oxide nanorod arrays have been grown on Si(100), Si(111), and glass substrates by low-pres-sure chemical vapor deposition from elemental zinc and oxygen. Under the experimental conditions of this study, nanorods grow along the c-axis and are predominantly normal to the substrate surface, independent of the crystallographic orientation of the substrate. The cathodoluminescence spectra of all the samples obtained show one strong emission band in the UV spectral region, due to free-exciton recombination, which attests to good stoichiometry of the ZnO nanocrystals. The uniformity of the arrays correlates with the density of nanorods per unit area and their thickness.

Using the X-ray-beam-induced current (XBIC) method, stacking faults in hexagonal silicon carbide 4H-SiC are studied. It is shown that the XBIC method using a laboratory source makes it possible to reveal extended defects in samples with a submicron diffusion length and anomalous bright contrast. The fault contrast is measured and compared with the contrast obtained in the electron-beam-induced current (EBIC) method. Discussion of the obtained results is presented.

The features of formation of silicon structures with a periodically varying porosity are investigated by X-ray diffractometry. It is revealed that the magnitude of anode current density corresponding to the formation of a layer with higher porosity that is part of a multilayer porous structure also affects the porosity of a second, less porous layer. As time elapses, the single-crystalline matrix of which porous layers consist is amorphized and a structure consisting of amorphous layers with a periodically varying density arises.

Equations describing the coherent and diffuse scattering in a crystal modulated by a surface acoustic wave (SAW) are derived using the dynamical X-ray diffraction theory. The effect of depth attenuation of the Rayleigh surface wave amplitude on the crystal rocking curve profiles is investigated. Results of the numerical simulation of the dynamical diffraction in a mosaic crystal modulated by a SAW, taking into account a block size distribution, are presented. It is shown that the diffuse scattering is distributed in the reciprocal space not only in the vicinity of the main diffraction peak but also about the satellite diffraction peaks, and this distribution depends on the size fluctuations of the crystal defects. Theoretical reciprocal space maps and rocking curves are compared with the corresponding experimental results.

The dynamical theory based on Takagi-Taupin equations was used to model x-ray diffraction by the Z-cut of a LiNbO 3 crystal with short period regular domain structure. It found that the presence of even satellites on the x-ray diffraction spectra caused by the crystal lattice deformation. A proposed model of the deformation allowed us to achieve a very good agreement with the experimental data.

The behavior of LiNbO3 and LiTaO3 crystals with domain structures in an external electric field was studied using high-resolution X-ray diffractometry and topography. Domain structures in Z-cut LiTaO3 and Y-cut LiNbO3 crystals have been formed by the aftergrowth thermoelectricall treatment technique were investigated. Strong elastic distortions near different domain boundaries in the Y-cut LiNbO3 crystal were detected. The possibility of using X-ray diffraction to measure piezoelectric charge constants tensor components is demonstrated.

The process of diffuse x-ray scattering from a crystal modulated by surface acousdtic wave is considered. It is shown that the angular distribution of the diffuse scattering intensity depends on variation of the gradient of the ultrasonic wave amplitude in depth of the crystal. This distribution is formed both in the vicinity of the main diffraction peak and around its satellites. Theoretical reciprocal space maps of the diffuse scattering intensity distribution are obtained and compared to the experimental data.

X-ray topography is first used to totally examine the fundamental modes of acoustic oscillations in the bulk-acoustic-wave (BAW) resonator on the base of an AT-cut quartz crystal at the first and third harmonics. As is evident from the experiments, the anharmonic longitudinal oscillations of the resonator can be visualized, just as the fundamental transverse acoustic oscillations can be. The amplitude-frequency response (AFR) is related to the frequency dependence of diffracted x-ray intensity.

In the last two decades, diluted magnetic semiconductors have attracted great attention as promising materials for spintronics applications. [K. Sato, H. Katyama-Yoshida, Jpn. J. Phys., Part 2 39 (2000) L555] theoretically predicted that ZnO doped with V, Cr, Fe, Co, and Ni can be ferromagnetic. This has been recently confirmed experimentally for vanadium doped ZnO films which were grown on sapphire substrates, using laser deposition technique [H. Saeki, H.N. Tabata, T. Kawai, Solid State Commun. 120 (2001) 439]. In the present work, high-dose vanadium implantation was used to produce Zn 1− x V x O ( x ∼ 0.10) thin film structures (250 nm thick) that had been epitaxially grown on sapphire substrates. Implantation with the dose 2 × 10 16 cm −2 was performed to reach a maximum vanadium concentration of 10 at%. To avoid ZnO film amorphization due to radiation damage accumulation [S.O. Kucheyev, J.S. Williams, C. Jagadish, J. Zou, C. Evans, A.J. Nelson, A.V. Hamza, Phys. Rev. B 67 (2003) 094115], all implants were done at elevated temperatures 300 and 400 °C and ion current density 10 μA/cm 2 . X-ray diffraction, SIMS and photoluminescence techniques were exploited to study the implanted samples. No luminescence was observed in the implanted samples after implantation procedures. However, annealing at 800 °C for 30 min gave rise to ZnO crystal structure improvement. This implies that healing of implantation induced defects is possible even after heavy-ion bombardment. As a result, the photoluminescence peak at 3.359 eV related to the donorbound exiton was detected.

Results from using the current method, in which a current is induced by a focused X-ray beam (XBIC = X-ray beam induced current) on a laboratory source are presented. It is shown that by reducing the X-ray probe sizes and improving the resolution, there is a gain in contrast increase for obtained images of grain boundaries in a crystal.

Pseudomorphic Si0.76Ge0.24/Si heterostructures grown by molecular-beam epitaxy were irradiated with 350-keV Ge+ ions at a temperature of 400°C so that the peak of the ions’ energy losses was located within the silicon substrate (deeper than the SiGe-Si interface). The effect of ion implantation on the relaxation of elastic stresses and the defect structure formed as a result of postimplantation annealing is studied. It is found that annealing at a temperature even as low as 600°C makes it possible to ensure a very high degree of relaxation of elastic stresses in the heterostructure and a comparatively low density of threading dislocations in the SiGe layer (

The dynamical theory was used to model X-ray diffraction by the YZ-cut of an LiNbO3crystal modulated by surface acoustic waves (SAWs). It includes both the calculation of the crystal lattice deformation, induced by a surface wave of Rayleigh type, and the simulation of X-ray wavefields in the crystal based on Takagi–Taupin equations. A detailed discussion is included on the effect of peak splitting occurring at high acoustic amplitudes. The developed theory entirely describes this effect and proves to be a powerful tool for understanding X-ray diffractometry and topography measurements by SAW-modulated crystals.

X-ray diffraction on the X cut of a langasite crystal (La3Ga5SiO14) modulated by a Λ=12 μm Rayleigh surface acoustic wave (SAW) has been studied at the ESRF synchrotron radiation source. Due to the sinusoidal modulation of the crystal lattice involved by the SAW diffraction satellites appear on the rocking curve, with their number, angular positions, and intensities depending on the amplitude and wavelength of the ultrasonic superlattice. Full extinction of a specific satellite could be performed by adjusting the acoustic amplitude. It is shown that x-ray diffraction can be used to study surface acoustic wave field distributions in crystals.

Pseudomorphic Si0.76Ge0.24/Si heterostructures grown by molecular beam epitaxy were implanted with Ge+ ions at 400 °C in such a way that an ion-damaged region was located below the SiGe/Si interface. The effect of Ge+-ion irradiation on strain-relaxation rate and defect structure in the heterostructures was studied by transmission electron microscopy (TEM), X-ray diffraction (XRD), atomic force microscopy (AFM), and low-temperature photoluminescence (PL). It was found that annealing at a temperature as low as 600 °C resulted in very high degree of strain relaxation, while density of threading dislocations was low (

The effect of non-equilibrium point defects on strain relaxation in pseudomorphic Si 0.76 Ge 0.24 /Si heterostructures was studied by X-ray diffraction (XRD) and low-temperature photoluminescence (PL). The overcritical Si 0.76 Ge 0.24 layer was grown by molecular beam epitaxy at relatively low temperature in order to avoid strain relaxation during the growth and then the non-equilibrium point defect were introduced by Ge + ion implantation. The samples were annealed in the temperature range from 500 to 600 °C. The ion-irradiated heterostructures showed considerably different relaxation behavior than the unimplanted samples. For the same heat-treatment conditions, the degree of relaxation was found to increase as the implantation dose rose.

Acoustically stimulated charge transport in solids was studied using the scanning electron microscopy method (SEM). The surface acoustic wave on the surface of the YZ-cut of a LiNbO3 crystal was visualized by registration of low-energy secondary electrons in SEM, and the charge distribution on the crystal surface was visualized using the electron beam induced current method. To register the induced current, an interdigital transducer structure was formed from graphene on the crystal surface. It was shown that the charge distribution on the crystal surface corresponds to the distribution of the acoustic wave field on the crystal surface.

A functional test for a pulse picker for synchrotron radiation was performed at Diamond Light Source. The purpose of a pulse picker is to select which pulse from the synchrotron hybrid-mode bunch pattern reaches the experiment. In the present work, the Bragg reflection on a Si/Bsub4/subC multilayer was modified using surface acoustic wave (SAW) trains. Diffraction on the SAW alters the direction of the x rays and it can be used to modulate the intensity of the x rays that reach the experimental chamber. Using electronic modulation of the SAW amplitude, it is possible to obtain different scattering conditions for different x-ray pulses. To isolate the single bunch, the state of the SAW must be changed in the short time gap between the pulses. To achieve the necessary time resolution, the measurements have been performed in conical diffraction geometry. The achieved time resolution was 120 ns.

We examine the current state, prospects for development, and the application of X-ray optics at the IMT-IHPM: X-ray diffraction optics based on X-ray multilayer mirrors and crystals, X-ray acousto-optics based on X-ray diffraction by acoustically modulated crystals, and the application of X-ray methods of diagnostics for the investigation of piezoelectric crystals.

Photolithography together with ion beam etching was used for fabrication of high temperature SAW devices. Ir thin film of 0.3 µm thick was deposited by magnetron sputtering without additional adhesion layers and than Ir film was annealed after electrode patterning in different conditions. The resistivity of magnetron sputtered thick Ir films drops noticeably after annealing. However, this process requires special care in order to avoid delaminating of the film due to developing high stress during such procedures. We have annealed the substrates with Ir films in different regimes and in different gas/vacuum conditions. The results of these studies have shown that annealing in air up to about 500 °C decreases the Ir film resistivity 1.5–2 times. Vacuum annealing did not show much improvement in comparison to open air annealing. Magnetron sputtered thin Ir films have somewhat porous structure allowing oxygen to diffuse from the substrate surface through Ir films. Resonator structures with thick Ir electrodes were prepared and tested. Examples of the resonator structures show very promising properties, such as high conductance and high Q-factor.

We directly measured phase-matching directions of second harmonic, sum, and difference frequency generations in the Langatate La₃Ga(5.5)Ta(0.5)O₁₄ (LGT) uniaxial crystal. The simultaneous fit of the data enabled us to refine the Sellmeier equations of the ordinary and extraordinary principal refractive indices over the entire transparency range of the crystal, and to calculate the phase-matching curves and efficiencies of LGT for infrared optical parametric generation.

A five-component ordered crystal of lanthanum-gallium silicate family Ca3NbGa3Si2O14 (CNGS) was grown by the Czochralski method. The unit cell parameters were determined by using the powder diffraction technique. Independent piezoelectric strain coefficients d11 and d14 were measured by high-resolution X-ray diffraction under the external electric field application which caused changes in the interplanar spacing because of the reverse piezoelectric effect. Surface acoustic wave (SAW) propagation in CNGS crystal was investigated by X-ray diffraction method at the synchrotron radiation source BESSSY II. The velocities of SAW propagation and power flow angles were measured in the Y-, X-, and yxl/+36o-cuts of CNGS crystal.

X-ray diffraction on disordered La3Ga5SiO14 (LGS) and ordered Ca3TaGa3Si2O14 (CTGS) crystals modulated by surface (SAW) and pseudo-surface acoustic waves (PSAW) with wavelength of A=6 μm was studied using a double axis X-ray diffractometer at the BESSY II synchrotron radiation source. The propagation of SAW and PSAW leads to sinusoidal modulation of the crystal lattice and gives rise to diffraction satellites on the rocking curve, with the intensity and angular divergence between the diffraction satellites depending on the wavelength and amplitude of the crystal lattice acoustic modulation. The analysis of diffraction spectra enables the determination of the amplitude and acoustic wavelengths, power flow angles of acoustic energy propagation.

The domain walls in LiNbO3 are studied using X-ray topography, X-ray diffraction, and scanning electron microscopy. It is shown that the regions of distortions of the crystal lattice near the domain walls of different types are different and have lateral sizes of 100–200 μm. The character and the magnitude of the distortions are substantially dependent on the method of formation of the domain structure. Under irradiation in a scanning electron microscope, the crystal region up to 25 μm in width near the “tail-to-tail” domain walls is charged more slowly and, unlike the “head-to-head” domain walls, exhibits a dynamic charge image in the secondary-electron regime.

The propagation of a high amplitude surface acoustic wave in an Al thin film induces a large-scale electromigration phenomenon resulting in a permanent etching of the acoustic field in the film. The etched patterns depend on the time of propagation and on the acoustic characteristics. Preliminary observations of a few grooved structures in Al films have been performed by different techniques. A first explanation of this phenomenon based on dynamical Grinfeld instabilities is proposed. By providing permanent pictures of acoustic fields emitted by transducers, this effect could be used to perform imaging of surface acoustic wave propagation.

Second generation of grazing-incidence-phase Fresnel zone plates is presented in this paper. The term grazing-incidence discrete Fresnel lens (GIDFL) for these zone plates is proposed. This lens performs a multilevel phase modulation of the incident X-ray radiation. With the increase of the number of levels, the GIDFL virtually becomes an ideal kinoform zone plate. X-ray optical properties of a four-level GIDFL are studied here. It is found that this lens is capable of focusing X-ray radiation with an efficiency of 75%. A model is proposed which describes the diffraction properties of these lenses and allows one to calculate the focal spot intensity.

Lithium tantalate crystals under the action of an external electric field have been studied by x-ray diffractometry. Both single-domain samples and crystals with a regular domain structure have been investigated. In the case of a single-domain crystal, the angular position of the Bragg peak varies under the action of an external electric field due to the reverse piezoelectric effect. According to this variation, the corresponding tensor component of piezoelectric constants can be calculated. In the crystal with a regular domain structure, a surface relief appears under the action of an external electric field. Piezoelectric constants can also be calculated using this relief.

X-ray diffraction by standing surface acoustic waves was investigated under total external reflection conditions. A standing surface acoustic wave was formed on the surface of a YZ-cut of a LiNbO 3 crystal by superposition of two travelling surface acoustic waves. The diffracted X-ray radiation intensity was found to oscillate with twice the frequency of the surface acoustic wave excitation.

We present experimental and theoretical results of X-ray focusing by a grazing incidence phase Fresnel zone plate modulated by a surface acoustic wave. The sinusoidal modulation of the Fresnel zone plate introduces diffraction satellites which can simultaneously be focused and deviated by changing the acoustic wavelength. This association could find some applications in the design of new X-ray optic systems.

The grazing incidence diffraction of an X-ray beam on surface acoustic waves (SAW) gives rise to diffraction satellites. A new high-frequency chopper for synchrotron radiation is presented here, based on this interaction. The temporal structure of the satellite intensities appearing in the diffracted beam can be directly correlated to the temporal structure of the acoustic waves. By electronic pulsing of the SAW emission and synchronization with the arrival of the synchrotron X-ray pulses, it is possible to select the X-ray flashes which will be diffracted in the satellites. A selection of 20% of each single X-ray pulse and an elimination of 99.7% of the unwanted ones in the hybrid mode of the ESRF (repetition frequency ∼350 kHz) has been achieved.

This paper reports the investigation of the X-ray Bragg diffraction on a multilayer mirror modulated by a short wavelength (12 μm) surface acoustic wave. Useful parameters to determine the diffraction pattern are the amplitude, the period of the surface acoustic wave, and the deviation of the incident angle from the exact Bragg position. It is shown that changing the incident angle induces some variations in the distribution of the diffracted intensity between the diffraction orders. A model based on the dynamic diffraction theory has been developed and is compared to the experimental results.

This paper reports a scanning electron microscopy study of the surface acoustic wave interaction with regular domain structure in LiTaO3 crystal. The regular domain structure was formed by thermoelectrical treatment after growth. The process of the surface acoustic wave propagation along domain structure and waveguide properties of the domain structure were investigated.

Independent piezoelectric strain coefficients d11 and d14 in disordered La3Ga5.3Ta0.5Al0.2O14 (LGTA) and ordered Ca3TaGa3Si2O14 (CTGS) crystals of the langasite family were measured by high-resolution X-ray diffraction (HRXRD) under external electric field application which causes changes in the interplanar spacing because of the reverse piezoelectric effect. The experiment showed that the piezoelectric strain coefficients can be precisely determined by measuring changes in the interplanar spacing using the optical scheme of a triple-axis X-ray diffractometer. The measured independent piezoelectric strain coefficients d11 and d14 for LGTA and CTGS crystals were d11(LGTA)=6.455·10-12 C/N, d14(LGTA)=-5.117·10-12 C/N; d11(CTGS)=3.330·10-12 C/N, d14(CTGS)=-15.835·10-12 C/N.

Direct imaging of a 10 μm surface acoustic wave (SAW) propagation in a La3Ga5SiO14 (LGS) crystal was obtained on the ESRF synchrotron radiation source in the saggital diffraction geometry using the Talbot effect. Imaging of the SAW wave field with the period 10 μm was observed at a distance corresponding to the Talbot distance. It is shown that the presence of the growth banding in the crystal does not influence on the propagation of acoustic wave-fields in the crystal nor does it cause a distortion of the SAW wave front.

X-ray diffraction on the La3Ga5SiO14 (LGS) crystal modulated by surface (SAW) and pseudo-surface acoustic waves (PSAW) with wavelength of Λ=6 μm was studied using a double axis X-ray diffractometer at the BESSY II synchrotron radiation source. The propagation of SAW and PSAW leads to sinusoidal modulation of the crystal lattice and gives rise to diffraction satellites on the rocking curve, with the intensity and angular divergence between the diffraction satellites depending on the wavelength and amplitude of the crystal lattice acoustic modulation. The analysis of diffraction spectra enables the determination of the amplitude and acoustic wavelengths, and power flow angles of acoustic energy propagation. The investigation of acoustic wave fields showed that PSAW is a flowing back wave.

A five-component crystal of lanthanum-gallium silicate group La3Ga5.3Ta0.5Al0.2O14 (LGTA) was grown by the Czochralski method. The LGTA crystal possesses unique thermal properties and substitution of Al for Ga in the unit cell leads to a substantial increase of electrical resistance at high temperatures. The unit cell parameters of LGTA were determined by powder diffraction. X-ray topography was used to study the crystal structure perfection: the growth banding normal to the growth axis were visualized. Excitation and propagation of surface acoustic waves (SAW) were studied by the double crystal X-ray diffraction at the BESSY II synchrotron radiation source. The analysis of the diffraction spectra of acoustically modulated crystals permitted the determination of the velocity of acoustic wave propagation and the power flow angles in different acoustic cuts of the LGTA crystal.

Using x-ray diffraction technique temperature dependence of SAW excitation frequency was measured for temperature range from 20 to 400 °C. Crystal lattice deformation caused by SAW propagation was calculated.

Bulk regular domain structures created in a LiNbO3 crystal by aftergrowth thermoelectrical treatment technique were studied by high-resolution x-ray diffraction and topography. Topographic contrast can be observed between neighboring domains and is related to the difference in the direction of spontaneous polarization vectors. In the Y-cut case, x-ray topography allows the determination of positively or negatively charged domain boundaries. It is also shown that x-ray diffraction can be used to study elastic deformation around domain walls.

This paper reports a scanning electron microscopy study of the interaction between surface acoustic waves and ferroelectric domain structures in LiNbO3 crystals. The domains were formed by thermoel...

This paper reports the first attempt to carry out a focusing followed by a space-time scanning of a synchrotron X-ray beam. The focusing is performed through an elliptical multilayer Bragg-Fresnel lens while the space-time scanning is due to the grazing incidence diffraction on the YZ -cut of a LiNbO 3 crystal modulated by pulsed surface acoustic waves. It opens the field of a new generation of X-ray beam control devices which should be of interest for X-ray scanning microscopy or time resolved spectroscopy. These experiments were carried out at LURE (Orsay, France).

A phase Fresnel zone plate for two-dimensional X-ray focusing at grazing incidence was fabricated. A 4 × 1 μm2 X-ray source image was obtained for wavelength λ = 1.54 A .

Space-time modulation of an X-ray beam is investigated by total external reflection on a YZ-cut of a LiNbO/sub 3/ crystal modulated by surface acoustic waves. It is shown that the X-ray diffraction is determined by the amplitude and the wavelength of the surface acoustic waves. Both experimental and theoretical studies have revealed the possibility of fabricating X-ray optical elements based on space-time modulation by controlling the wavelength and the pulse modulation of the surface acoustic waves. These experiments were carried out at CNRS (Grenoble, France) using a rotating copper anode. >