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We report on determining the optical constants of Ta in the sub-extreme ultraviolet (EUV) spectral range 5.0–24.0 nm from the angle-dependent reflectance (ADR) measured using monochromatized synchrotron radiation. Two sputtered samples with differing thicknesses were investigated. Complementarily x-ray reflectance was measured at shorter wavelengths and evaluated by Fourier transform to facilitate an unambiguous selection of a model for the data evaluation based on an inverse solution of the Fresnel’s equations for a layered system. Bayesian inferences coupled with a Nested Sampling (NS) algorithm were utilized to derive the optical constants with their corresponding uncertainties. This report further emphasizes the applicability of an acclaimed NS algorithm on a high-dimensional inverse problem. We explore the possibility of addressing the correlations between the optical constants of thin films and their structural parameters based on other established studies.

ispartof: OPTIK vol:273 status: published

The optical constants of two Ta-Co binary alloys are determined in the spectral range 8.0 nm–22.0 nm using angle-dependent reflectometry (ADR). The extreme-ultraviolet reflectivity (EUVR) profiles of the alloys were measured using highly monochromatized synchrotron radiation from sputtered thin films, each with a nominal thickness of 30.0 nm. Concerning the alloys, the inability to predict the variability of the optical constants' profiles in the vicinity of cobalt’s M-absorption edge region gives unique proof for the need to derive a more complete theory for predicting the optical constants. Markov chain Monte Carlo (MCMC) based Bayesian inferences, and frequency analysis of X-ray reflectivity (XRR) data were utilized to treat the relevant inverse-problem needed for determining the optical constants. An approach is presented here where both the optical constants of the alloys and their surface layers are simultaneously sampled. The results of this report are apropos to strengthen customizing multilayer mirrors (MLMs) and similar ad hoc optical components intended for the extreme-ultraviolet (EUV) spectral range.

Ship motion planning constitutes the most critical part in the autonomous navigation systems of marine autonomous surface ships (MASS). Weather and ocean conditions can significantly affect their navigation, but there are relatively few studies on the influence of wind and current on motion planning. This study investigates the motion planning problem for USV, wherein the goal is to obtain an optimal path under the interference of the navigation environment (wind and current), and control the USV in order to avoid obstacles and arrive at its destination without collision. In this process, the influences of search efficiency, navigation safety and energy consumption on motion planning are taken into consideration. Firstly, the navigation environment is constructed by integrating information, including the electronic navigational chart, wind and current field. Based on the environmental interference factors, the three-degree-of-freedom kinematic model of USVs is created, and the multi-objective optimization and complex constraints are reasonably expressed to establish the corresponding optimization model. A multi-objective optimization algorithm based on HA* is proposed after considering the constraints of motion and dynamic and optimization objectives. Simulation verifies the effectiveness of the algorithm, where an efficient, safe and economical path is obtained and is more in line with the needs of practical application.

Development of efficient absorber masks and highly reflective mirrors in the EUV spectral range is a key challenge for upcoming lithography techniques in semiconductor technology. There is an improved need to precisely know the optical constants of the materials at hand for specialized applications such as phase shifting absorber masks. A further field of application is the interpretation and accompanied modeling of scattering data of complex nanostructures. At PTB, we measured the spectral reflectance of thin film samples in the angular range from normal incidence to grazing incidence in the range of 10nm to 20nm using PTB’s lubrication-free Ellipso-Scatterometer at the soft x-ray beamline at the electron storage ring BESSY II. This allowed us to determine the optical constants of a variety of metals, semimetals and their alloys from model fits based on Fresnel’s equations for layered material stacks.

Novel mask absorber designs are catching the attention of the EUVL community due to their ability to mitigate mask 3D effects. Material selection is part of such an optimization. We propose several candidates as novel EUV lithography mask absorbers, namely TaTeN, Ru–Ta, and Pt–Mo alloys. The choice of these materials is based on their theoretical performance evaluated by EUV imaging simulation based on their complex refractive index N ( λ ) = n ( λ ) + ik ( λ ) , where the optical constants n and k relate to the phase velocity and the absorption of electromagnetic radiation with a wavelength λ, respectively. The materials are deposited as thin films on Si substrate with an additional Ru layer to mimic the cap of the multilayer mirror on the real mask. The experimental n and k values are determined by analyzing EUV reflectivity data obtained using a 13.5-nm synchrotron EUV radiation. The imaging simulation presented consists of calculating several imaging metrics including non-telecentricity, normalized image log-slope, and threshold-to-size for specific use cases using the novel absorber. It also compares the proposed materials with the reference TaBN absorber. TaTeN shows higher absorption than TaBN and refraction closer to 1, which improves phase matching for a high k absorber. The refractive index of Ru–Ta and Pt–Mo alloys exhibits a large difference from that of air and provides the required phase shift of attenuated phase shift masks. The characterizations of these materials target the requirements of an EUVL mask: durability for mask cleaning, mask lifetime, and etchability for mask patterning. The stability is first tested against several standard mask cleaning solutions by a beaker test for up to 24 h. The samples are also exposed to hydrogen plasma to imitate the working environment in an EUV scanner. Concerning material patterning, chemical reactive ion etch is applied for preliminary tests. A proper etch recipe is found for TaTeN with a good etch rate (about 60 nm / min) and good selectivity to the Ru underlayer (Ru etch is negligible).

In this paper, amphiphilic conjugated triphenylamine-porphyrins TPA-Por-TPA and TPA-Por were designed and synthesized. The water-soluble nanostructures TPA-Por-TPA NPs and TPA-Por NPs spontaneously assembled after π-π stacking, which can be changed by improving the internal transfer ability of electrons. The intercalation and external binding modes of these free porphyrins and nanoporphyrins interacting with ct-DNA were confirmed by UV-vis and fluorescence spectroscopy. Reactive oxygen species (ROS) production was studied by 2',7'-dichlorofluorescein diacetate, demonstrating that the rate of production of ROS is TPA-Por-TPA NPs > TPA-Por-TPA > TPA-Por NPs > TPA-Por. In addition, the structure of the NP enhanced the acceptor-donor conjugated structure, resulting in fluorescence quenching and promoting non-radiative heat generation. The photothermal conversion efficiencies of the TPA-Por-TPA NPs and TPA-Por NPs were measured and calculated to be 34.89% and 37.99%, respectively. At the same time, the three nanomaterials showed good photocytotoxicity, and the IC50 of the TPA-Por-TPA NPs and TPA-Por NPs was 32.18 and 36.62 μg ml-1, respectively, at 10 min after laser irradiation. The cellular uptake and subcellular localization of these NPs were further evaluated through a confocal laser scanning microscope. The results showed that the conjugated NPs have good biocompatibility properties in the cancer cells. These properties make it possible for triphenylamine porphyrin NPs to become photosensitizers for the photodynamic and photothermal synergistic treatment of tumors, and have potential prospects for applications in cancer diagnosis and treatment.

Ru4-xTax (x = 1,2,3) alloys are studied as absorber candidates for EUV low-n mask. We report the morphology, surface roughness as well as the chemical composition of the as-deposited alloy films for better theoretical model building of the EUVL absorber stack. Their refractive indices are reconstructed by optimizing measured EUV reflectivity data for the purpose of enabling rigorous EUVL imaging calculations in the future work. The stabilities (both physical and chemical) of these absorber candidates are verified which contribute to a long lifetime of the mask in its working environment. This includes the resistance assessments of the thin films against high temperature up to 500 °C, different mask cleaning solutions and hydrogen environment which is present in EUV scanners. Etching of RuTa is explored using halogen-based reactive ion etch technique. A low etch rate is obtained with a moderate etch selectivity to Ru, which is the capping layer of multilayer mirror on a EUVL mask.

Novel mask absorber designs are calling attention of the EUVL community due to their ability to mitigate mask 3D effects. Material selection is part of such optimization [1]. In this paper we propose several candidates as novel EUV lithography mask absorbers, namely TaTeN, Ru-Ta and Pt-Mo alloys. The choice of these materials is based on their theoretical performance evaluated by EUV imaging simulation based on their complex refractive index N(λ) = n(λ) +ik(λ), where the optical constants n and k relate to the phase velocity and to the absorption of an electromagnetic radiation with a wavelength λ, respectively. The materials are deposited as thin films on Si substrate with an additional Ru layer to mimic the cap of multilayer mirror (MLM) on the real mask. The experimental n and k values are determined by analyzing EUV reflectivity data obtained using a 13.5 nm synchrotron EUV radiation. The imaging simulation presented in this paper consists of calculation of several imaging metrics like non-telecentricity, normalized image log-slop (NILS), and threshold-to-size for specific use cases using the novel absorber. It also compares the proposed materials to the reference TaBN absorber. TaTeN shows higher absorption than TaBN and refraction closer to 1, which improves phase matching for a high k absorber. The refractive index of Ru-Ta and Pt-Mo alloys exhibits a large difference to that of air and provides the required phased shift of attenuated phase shift masks [2]. The characterizations of these materials target the requirements of an EUVL mask: durability for mask cleaning, mask lifetime and etchablity for mask patterning. The stability is first tested against several standard mask cleaning solutions by beaker test up to 24 hours with the film structure monitored by X-ray reflectivity analysis. The samples are also exposed to hydrogen plasma to imitate the working environment in a EUV scanner. Material integrity is checked with Rutherford backscattering spectroscopy before and after the exposure. Concerning material patterning, chemical reactive ion etch is applied for preliminary tests. A proper etch recipe is found for TaTeN with good etch rate (about 60 nm/min) and good selectivity to Ru underlayer (Ru etch is ignorable).

International audience; We characterize nano-scale periodic Sc/Mg two-layer, Sc/Mg/Co tri-layers and Sc/Co/Mg/Co quadri-layer designed as dispersive elements for x-ray spectroscopy in the nitrogen K range (390 eV). The samples are prepared by magnetron sputtering with Mg and Sc layers being a few nanometers thick and Co layers being of sub-nanometric thickness. We apply non-destructive (x-ray reflectivity and x-ray fluorescence in standing wave mode) and destructive (transmission electron microscopy) techniques to obtain a relevant description of the deposited stacks. It turns out that a strong interdiffusion takes place in the two-layer leading to poor reflective properties. Interdiffusion also occurs in the tri-layers and quadri-layer but between the Sc and Co layers. These systems can be considered as periodic ScCo/Mg two-layers with well-defined layers. As a consequence, the Sc/Co/Mg/Co multilayer is found interesting to use for spectroscopy as a reflectance of 32% is expected in the N K range in the water window range.

International audience; By combining Kossel diffraction with particle induced X-ray emission, we have developed a new methodology to analyze nano-scale thin films. We report the Kossel diffraction generated by irradiating Pd/Y based nano-scale periodic multilayers with 2 MeV protons. The intensity of characteristic Pd Lα X-ray emission is measured as a function of the detection angle (grazing exit). An oscillation of its intensity is observed when the detection angle varies around the Bragg angle, which corresponds to the energy of the emission and the period of the multilayer. Use of the X-ray color camera enables the whole setup to be fixed so that no angular scan is required, greatly simplifying the experimental condition. From the features of the Kossel curves, we are able to deduce that nitrided Pd/Y multilayers exhibit much less layer intermixing than the non-nitrided multilayers. The experimental results show that it is possible to distinguish by the shape of Kossel curves of multilayers with B 4 C barrier layers located in different interfaces. This demonstrates that Kossel diffraction is structural sensitive.

A refined model of an extreme ultraviolet (EUV) mask stack consisting of the Mo/Si multilayer coated by a Ru protective layer and a TaBN/TaBO absorber layer was developed to facilitate accurate simulations of EUV mask performance for high-NA EUV photo-lithography (EUVL) imaging. The model is derived by combined analysis of the measured EUV and x ray reflectivity of an industry-representative mask blank. These two sets of measurements were analyzed using a combined free-form analysis procedure that delivers high-resolution x ray and EUV optical constant depth profiles based on self-adapted sets of sublayers as thin as 0.25 nm providing a more accurate description of the reflectivity than obtained from only EUV reflectivity. “Free-form analysis” means that the shape of the layer interfaces in the model is determined experimentally and is not given a priori by the structure model. To reduce the numerical effort for EUV imaging simulations, a low-resolution model of the multilayer and absorber stack with sublayer thicknesses larger than 2 nm, that fits to only the EUV reflectance, was derived from the high-resolution model. Rigorous high-NA EUVL simulations were done to compare the performance of the new model to our previous work [Proc. SPIE 8886, 88860B (2013)PSISDG0277-786X10.1117/12.2030663].

Efficient multilayer optics for radiation in the water window range are difficult to manufacture due to extremely small layer thicknesses and severe intermixing of elements between the layers. Therefore, adequate analytics and short feedback loops are of utmost importance for manufacturers to improve performance and efficiency. We show the possibility for non-destructive elemental depth profiling with commercial laboratory equipment using four real-life CrSc multilayer samples. Comparative measurements at the laboratory of PTB at the synchrotron radiation facility BESSY II confirm the results and prove the potential of laboratory equipment for the reliable analysis of stratified materials with sub-nanometer layer thicknesses.

International audience; The Kossel effect is the diffraction by a periodically structured medium, of the characteristic X-ray radiation emitted by the atoms of the medium. We show that multilayers designed for X-ray optics applications are convenient periodic systems to use in order to produce the Kossel effect, modulating the intensity emitted by the sample in a narrow angular range defined by the Bragg angle. We also show that excitation can be done by using photons (X-rays), electrons or protons (or charged particles), under near normal or grazing incident geometries, which makes the method relatively easy to implement. The main constraint comes from the angular resolution necessary for the detection of the emitted radiation. This leads to small solid angles of detection and long acquisition times to collect data with sufficient statistical significance. Provided this difficulty is overcome, the comparison or fit of the experimental Kossel curves, i.e., the angular distributions of the intensity of an emitted radiation of one of the element of the periodic stack, with the simulated curves enables getting information on the depth distribution of the elements throughout the multilayer. Thus the same kind of information obtained from the more widespread method of X-ray standing wave induced fluorescence used to characterize stacks of nanometer period, can be obtained using the Kossel effect.

Gratings, one of the most important energy dispersive devices, are the fundamental building blocks for the majority of optical and optoelectronic systems. The grating period is the key parameter that limits the dispersion and resolution of the system. With the rapid development of large X-ray science facilities, gratings with periodicities below 50 nm are in urgent need for the development of ultrahigh-resolution X-ray spectroscopy. However, the wafer-scale fabrication of nanogratings through conventional patterning methods is difficult. Herein, we report a maskless and high-throughput method to generate wafer-scale, multilayer gratings with period in the sub-50 nm range. They are fabricated by a vacancy epitaxy process and coated with X-ray multilayers, which demonstrate extremely large angular dispersion at approximately 90 eV and 270 eV. The developed new method has great potential to produce ultrahigh line density multilayer gratings that can pave the way to cutting edge high-resolution spectroscopy and other X-ray applications., Fabrication of wafer-scale nanogratings for X-ray spectroscopy is difficult especially for very high line densities. The authors use vacancy epitaxy to fabricate sub-50-nm-periodicity gratings, coated with multilayers for efficient operation, for use in ultra-high resolution x-ray spectroscopy.

We present the observation of the angular distribution of a characteristic x-ray emission through a periodic multilayer. The emission coming from the substrate on which the multilayer is deposited is used for this purpose. It is generated upon proton irradiation through the multilayer and detected with an energy sensitive CCD camera. The observed distribution in the low detection angle range presents a clear dip at a position characteristic of the emitting element. Thus, such a device can be envisaged as a spectrometer without mechanical displacement and using various ionizing sources (electrons, x-rays, ions), their incident direction being irrelevant., 3 pages, 2 figures, 13 references

Pd/Y multilayers are high reflectance mirrors designed to work in the 7.5-11 nm wavelength range. Samples, prepared by magnetron sputtering, are deposited with or without B4C barrier layers located at the interfaces of Pd and Y layers to reduce interdiffusion, which is expected by calculating mixing enthalpy of Pd and Y. Grazing incident x-ray reflectometry is used to characterize these multilayers. B4C barrier layers are found effective on reducing the Pd-Y interdiffusion. Details of the composition of the multilayers are revealed by hard x-ray photoemission spectroscopy under x-ray standing waves effect. It consists in measuring the photoemission intensity from samples that perform an angular scan in the region corresponding to the multilayer period and the incident photon energy according to the Bragg law. The experimental result indicates that Pd does not chemically react with B nor C at the Pd-B4C interfaces while Y does at the Y-B4C interfaces. The formation of Y-B or Y-C chemical compound can be the reason why the interfaces are stabilized. By comparing the experimentally obtained angular variation of the characteristic photoemission with the theoretical calculation, the depth distribution of each component element can be interpreted., 13 pages, 8 figures, 1 tables, 19 references

V/Sc multilayer is experimentally demonstrated for the first time as a high reflectance mirror for the soft X-ray water window region. It primarily works at above the Sc-L edge (λ = 3.11 nm) under near normal incidence while a second peak appears at above the V-L edge (λ = 2.42 nm) under grazing incidence. The V/Sc multilayer fabricated with a d-spacing of 1.59 nm and 30 bilayers has a smaller interface width (σ = 0.27 and 0.32 nm) than the conventional used Cr/Sc (σ = 0.28 and 0.47 nm). For V/Sc multilayer with 30 bilayers, the introduction of B4C barrier layers has little improvement on the interface structure. As the number of bilayers increasing to 400, the growth morphology and microstructure of the V/Sc layers evolves with slightly increased crystallization. Nevertheless, the surface roughness remains to be 0.25 nm. A maximum soft X-ray reflectance of 18.4% is measured at λ = 3.129 nm at 9° off-normal incidence using the 400-bilayers V/Sc multilayer. According to the fitted model, an s-polarization reflectance of 5.2% can also be expected at λ = 2.425 nm under 40° incidence. Based on the promising experimental results, further improvement of the reflectance can be achieved by using a more stable deposition system, exploring different interface engineering methods and so on.

A series of five-membered N-heterocyclic carbene C,S palladium(II) π-allyl complexes were successfully developed and characterized. Structural analyses of these complexes revealed that the organopalladium chelates adopt a skew-envelope conformation with a trans disposition of the substituents on the metal chelate rings. Utilizing these C,S palladium(II) π-allyl complexes as catalysts, a catalytic system for the allylic amination reaction has been developed. A series of C–N bond formations between amines and unsymmetrically substituted allylic carbonates could be catalyzed efficiently by complex (±)-9 in a regioselective manner.

Palladium and platinum complexes containing a sulfur-functionalised N-heterocyclic carbene (S-NHC) chelate ligand have been synthesised. The absolute conformations of these novel organometallic S-NHC chelates were determined by X-ray structural analyses and solution-phase 2D (1)H-(1)H ROESY NMR spectroscopy. The structural studies revealed that the phenyl substituents on the stereogenic carbon atoms invariably take up the axial positions on the Pd-C-S coordination plane to afford a skewed five-membered ring structure. All of the chiral complexes are structurally rigid and stereochemically locked in a chiral ring conformation that is either (Rs ,S,R)-λ or (Ss ,R,R)-δ in both the solid state and solution.

Conference on X-Ray Lasers and Coherent X-ray Sources - Development and Applications, Prague, CZECH REPUBLIC, APR 24-26, 2017; International audience; Stimulated emission is a fundamental process in nature that deserves to be investigated and understood in the EUV and X-ray regimes. Today this is definitely possible through high energy density FEL beams. In this context, we show evidence for soft x-ray stimulated emission from a MgO solid target pumped by extreme ultraviolet FEL pulses formed in the regime of travelling-wave amplified spontaneous emission in backward geometry. Our results combine two effects separately reported in previous works: emission in a privileged direction and existence of a material-dependent threshold, for the stimulated emission. We have developed a theoretical framework, based on coupled rate and transport equations taking into account the solid density plasma state of the target. Our model, accounts for both observed mechanisms that are the privileged direction for the stimulated emission of the Mg L-2,L-3 characteristic emission and the pumping threshold.

We use hard x-ray photoemission spectroscopy combined with x-ray standing waves to characterize a series of Pd/Y multilayers designed to work in the 7.5-11 nm wavelength range. The samples, prepared by magnetron sputtering, are deposited either with or without nitrogen introduced in the sputtering gas. The aimed period of the samples is 4 nm. The experiments consist in obtaining the core level spectra of the various elements for a series of grazing angles. The angular scan is made in the range given by the Bragg law, the multilayer period and the incident photon energy. Given the period of the multilayer and the presence of a 2.5 nm-thick B4C capping layer, the photon energy is chosen to be 10 keV in order to probe the first 5-6 periods of the stack. Thus the Bragg angle is a little less than 1°. Rotating the sample enables putting the nodes of the electric field at some particular location of the stack, thus to make the excitation depth-selective, probing one interface or another or the center of one given layer. The changes of the chemical shift in the Pd 2p and 3d, Y 2p and 3d, O 1s, N 1s, C 1s and B 1s as a function of the angle, that is to say as a function of the location in the stack will give information about the possible interfacial process taking place in the Pd/Y multilayers.

International audience; The Kossel interferences generated by characteristic x-ray lines produced inside a periodic multilayer have been observed upon proton irradiation, by submitting a Cr/B4C/Sc multilayer stack to 2 MeV protons and observing the intensity of the Sc and Cr Kα characteristic emissions as a function of the detection angle. When this angle is close to the Bragg angle corresponding to the emission wavelength and period of the multilayer, an oscillation of the measured intensity is detected. The results are in good agreement with a model based on the reciprocity theorem. The combination of the Kossel measurements and their simulation, will be a useful tool to obtain a good description of the multilayer stack and thus to study nanometer-thick layers and their interfaces.

The segrosome of multiresistance plasmid TP228 comprises ParF, which is a member of the ParA ATPase superfamily, and the ParG ribbon–helix–helix factor that assemble jointly on the parH centromere. Here we demonstrate that the distinctive parH site (∼100-bp) consists of an array of degenerate tetramer boxes interspersed by AT-rich spacers. Although numerous consecutive AT-steps are suggestive of inherent curvature, parH lacks an intrinsic bend. Sequential deletion of parH tetramers progressively reduced centromere function. Nevertheless, the variant subsites could be rearranged in different geometries that accommodated centromere activity effectively revealing that the site is highly elastic in vivo. ParG cooperatively coated parH: proper centromere binding necessitated the protein's N-terminal flexible tails which modulate the centromere binding affinity of ParG. Interaction of the ParG ribbon–helix–helix domain with major groove bases in the tetramer boxes likely provides direct readout of the centromere. In contrast, the AT-rich spacers may be implicated in indirect readout that mediates cooperativity between ParG dimers assembled on adjacent boxes. ParF alone does not bind parH but instead loads into the segrosome interactively with ParG, thereby subtly altering centromere conformation. Assembly of ParF into the complex requires the N-terminal flexible tails in ParG that are contacted by ParF.

International audience; We study Cr/Sc-based multilayer mirrors designed to work in the water window range using hard and soft x-ray reflectivity as well as x-ray fluorescence enhanced by standing waves. Samples differ by the elemental composition of the stack, the thickness of each layer, and the order of deposition. This paper mainly consists of two parts. In the first part, the optical performances of different Cr/Sc-based multilayers are reported, and in the second part, we extend further the characterization of the structural parameters of the multilayers, which can be extracted by comparing the experimental data with simulations. The methodology is detailed in the case of Cr/B4C/Sc sample for which a three-layer model is used. Structural parameters determined by fitting reflectivity curve are then introduced as fixed parameters to plot the x-ray standing wave curve, to compare with the experiment, and confirm the determined structure of the stack.

International audience; A characteristic X-ray line emitted from an atom within a periodic structure can be diffracted by the (emitting) structure itself according to the Bragg law. The subsequent Kossel [1] interferences lead to a modulation of the x-ray line intensity as a function of the detection angle in the vicinity of the Bragg angle value [2]. Standing-wave mechanism and Kossel diffraction can be viewed as space reversed processes by virtue of the reciprocity theorem. Kossel interferences have been yet observed using incident X-ray radiation [3-4], electrons [1-2, 5] and ions [6], in crystals [2,5-6] and in periodic multilayers [2-4].In the present work, we have studied the characteristic Cr and Sc K emissions produced by a periodic Cr/B4C/S multilayer exposed to a beam of 2 MeV-protons. The period of the multilayer is close to 2 nm. The intensity of these two emission lines is measured as function of the grazing exit angle, i.e. the angle between the direction of the detector and that of the surface of the multilayer. In the case of the Sc K emission, in Figure 1 we compare the experimental results to those calculated combining a classical recursive approach to the reciprocity theorem. To our knowledge, it is the first time that ions are used to induce Kossel diffraction in a multilayer. Refined details about the structure of the stack could be obtained, especially the profile and nature of the interfaces.Figure 1: Measured (red) and calculated (blue) intensity of the Sc K emission as a function of the detection angle.[1] W. Kossel, V. Loeck and H. Voges, Z. Für Phys. 94, 139 (1935).[2] P. Jonnard P., J.-M. André, C. Bonnelle, F. Bridou and B. Pardo, Appl. Phys. Lett. 81 (8), 1524 (2002).[3] J.-P. Chauvineau and F. Bridou, J. Phys. IV 6, C7 (1996).[4] Y. Tu, Y. Yuan, K. Le Guen, J.-M. André, J. Zhu, Z. Wang, F. Bridou, A. Giglia and P. Jonnard, J. Synchrotron Radiat. 22, 1419 (2015).[5] V.V. Lider, Crystallogr. Rep. 56, 169 (2011).[6] V. Geist and R. Flagmeyer, Phys. Status Solidi A 26, K1 (1974).