Search

In recent years, interest in expanding from 2D to 3D systems has grown in the magnetism community, from exploring new geometries to broadening the knowledge on the magnetic textures present in thick samples, and with this arise the need for new characterization techniques, in particular tomographic imaging. Here, we present a new tomographic technique based on Fourier transform holography, a lensless imaging technique that uses a known reference in the sample to retrieve the object of interest from its diffraction pattern in one single step of calculation, overcoming the phase problem inherent to reciprocal-space-based techniques. Moreover, by exploiting the phase contrast instead of the absorption contrast, thicker samples can be investigated. We obtain a 3D full-vectorial image of a 800 nm-thick extended Fe/Gd multilayer in a 5$\mu$m-diameter circular field of view with a resolution of approximately 80 nm. The 3D image reveals worm-like domains with magnetization pointing mostly out of plane near the surface of the sample but that falls in-plane near the substrate. Since the FTH setup is fairly simple, it allows modifying the sample environment. Therefore, this technique could enable in particular a 3D view of the magnetic configuration's response to an external magnetic field., Comment: 11 pages, 8 figures

Sophisticated x-ray scattering experiments reveal charge dynamics in a model cuprate compound, providing crucial insight into the connection between high-temperature superconductivity and other electronic behaviors in these materials.

RIXS spectra are populated by features due to orbital, charge, and spin excitations. The correct assignment is usually based on their energy and on the incident polarization dependence. In addition, several ambiguities can be lifted by measuring the scattered photon polarization. Here, a polarization-resolved Cu ${L}_{3}$ RIXS systematic study of NdBa${}_{2}$Cu${}_{3}$O${}_{7\ensuremath{-}\ensuremath{\delta}}$ as a function of doping and momentum is presented. With the help of single-ion model calculations, a definitive assessment of orbital excitations is made, even in the doped materials where the intrinsic broadening smears spectral features.

Charge order has now been observed in several cuprate high-temperature superconductors. We report a resonant inelastic x-ray scattering experiment on the electron-doped cuprate ${\mathrm{Nd}}_{2\ensuremath{-}x}{\mathrm{Ce}}_{x}\mathrm{Cu}{\mathrm{O}}_{4}$ that demonstrates the existence of dynamic correlations at the charge-order wave vector. Upon cooling we observe a softening in the electronic response, which has been predicted to occur for a $d$-wave charge order in electron-doped cuprates. At low temperatures, the energy range of these excitations coincides with that of the dispersive magnetic modes known as paramagnons. Furthermore, measurements where the polarization of the scattered photon is resolved indicate that the dynamic response at the charge-order wave vector primarily involves spin-flip excitations. Overall, our findings indicate a coupling between dynamic magnetic and charge-order correlations in the cuprates.

The magnetisation dynamics of the vortex core and Landau pattern of magnetic thin-film elements has been studied using holography with extended reference autocorrelation by linear differential operator (HERALDO) [1–2].

Single-crystal Nd/Pr superlattices have been studied using resonance-enhanced magnetic X-ray scattering. Magnetic resonances were observed at the L II edges of Nd and Pr, so it was possible to study the magnetism of both components of a superlattice separately for the first time using synchrotron X-rays. The results demonstrate that the 5d bands are magnetically polarised in both elements, and suggest that the induced ordering in the Pr is localised. The induced moment profile across the Pr blocks has been determined and the results correlated with the observed magnetic coherence of the Nd. Thus new insight is obtained on the nature of the induced ordering of the Pr and on the interlayer coupling mechanism.

The half-metallic Heusler compound Co2MnSi is a very attractive material for spintronic devices because it exhibits very high tunnelling magnetoresistance ratios. This work reports on a spectroscopic investigation of thin Co2MnSi films as they are used as electrodes in magnetic tunnel junctions. The investigated films exhibit a remanent in-plane magnetization with a magnetic moment of about 5 μBwhen saturated, as expected. The low coercive field of only 4 mT indicates soft magnetic behavior. Magnetic dichroism in emission and absorption was measured at the Co and Mn 2p core levels. The photoelectron spectra were excited by circularly polarized hard X-rays with an energy of 6 keV and taken from the remanently magnetized film. The soft X-ray absorption spectra were taken in an induction field of 4 T. Both methods yielded large dichroism effects. An analysis reveals the localized character of the electrons and magnetic moments attributed to the Mn atoms, whereas the electrons related to the Co atoms contribute an itinerant part to the total magnetic moment.

Resonant Inelastic X-ray Scattering (RIXS) in the soft x-ray range is an element-specific energy-loss spectroscopy used to probe the electronic and magnetic excitations in strongly correlated solids. In the recent years, RIXS has been progressing very quickly in terms of energy resolution and understanding of the experimental results, but the interpretation of spectra could further improve, sometimes decisively, from a full knowledge of the polarization of incident and scattered photons. Here we present the first implementation, in a high resolution RIXS spectrometer used to analyze the scattered radiation, of a device allowing the measurement of the degree of linear polarization. The system, based on a graded W/B4C multilayer mirror installed in proximity of the CCD detector, has been installed on the AXES spectrometer at the ESRF; it has been fully characterized and it has been used for a demonstration experiment at the Cu L3 edge on a high-Tc superconducting cuprate. The loss in efficiency suffered by the spectrometer equipped with this test facility was a factor 17.5. We propose also a more advanced version, suitable for a routine use on the next generation of RIXS spectrometers and with an overall efficiency up to 10%., 26 pages, 8 figures

Resonant X-ray scattering experiments have been performed in 2.8% Cr-doped V 2 O 3 single crystal at the Vanadium K-photoabsorption edge. Using linear polarization analysis and comparing the angular dependence of scattered photons with structure factor calculations we can discriminate the nature of the different resonant X-ray processes involved in forbidden lattice reflections enhanced by resonances. We present an experimental method to extract information on local properties of edge-atom such as the anisotropy of the local atomic environment, the atomic magnetic moment orientation and orbital ordering.

Coherent X-ray-scattering measurements were performed in the type-I antiferromagnetic phase of UAs at the M IV uranium absorption edge. Speckle patterns from a magnetic reflection were followed up through the magnetic transition. The origin of the speckles is discussed in terms of antiferromagnetic domain configuration and fluctuations.

Frozen-in phason fluctuations in single grains of icosahedral Al-Pd-Mn quasicrystals have been studied by high-resolution coherent X-ray scattering. Bragg peak widths scale as expected for a distribution of uniform phason strains. Strong relaxation of the uniform phason strain is observed after sample annealing. Large intensity fluctuations or speckle patterns are observed in the Bragg peaks due to the uniform phason strain distribution in the sample. Speckle patterns are also observed in the diffuse scattering located close to the Bragg reflections and are related to long-wavelength phason fluctuations taking place in the sample.

Neutron diffraction studies of heavy rare-earth superlattices have revealed the stabilization of novel magnetic phases that are not present in bulk materials. The most striking result is the propagation of the magnetic ordering through nonmagnetic spacer materials. Here we describe some recent X-ray magnetic resonant scattering studies of light rare-earth superlattices, which illuminate the mechanism of interlayer coupling, and provide access to different areas of Physics, such as the interplay between superconductivity and magnetism. Magnetic X-ray diffraction is found to be particularly well suited to the study of the modulated magnetic structures in superlattices, and provides unique information on the conduction-electron spin–density wave responsible for the propagation of magnetic order.

The magnetic structures of Nd/Pr superlattices have been investigated using x-ray magnetic resonant scattering. Magnetic dipole resonances were observed at the edges of both components of the superlattices, proving that a coherent spin-density wave is established in the 5d bands of both elements. Multi- q magnetic structures were induced in the Pr, and the two components of the superlattice were found to adopt identical magnetic modulation vectors. Magnetic superlattice peaks were observed in Q-scans at both edges and from these we were able to determine the magnetization profiles in each component of the superlattice separately. From the width of the magnetic peaks in the wave-vector, , we were able to measure the magnetic coherence of the Nd, and the results demonstrate that the observed spin-density wave in the Pr is responsible for the coupling between successive Nd blocks.

The weak antiferromagnetic order of the heavy-fermion superconductor UPt3 has been investigated by elastic neutron-scattering measurements under applied uniaxial pressure up to 6 kbar along the a and c axes of the hexagonal crystal structure. For p||c the small antiferromagnetically ordered moment of 0.02 μB/U-atom shows a non-linear decrease for increasing pressures and is still not completely suppressed at the maximum applied pressure of 6 kbar. For p||a a significant increase in the magnetic Bragg peak intensity is observed, which suggests an incomplete domain repopulation and confirms the presence of a single-k structure.

The antiferromagnetism (AFM) and antiferroquadrupolar (AFQ) ordering in TmGa 3 was investigated by resonant x-ray scattering (RXS), using photons tuned to the Tm L 3 absorption edge. The AFQ RXS is most evident from an enhancement of the σσ intensity in the dipole energy threshold of the Tm L 3 edge. The AFQ order was found to have the same ordering wave-vector as the AFM q = (0,1/2,1/2). However, the AFQ and AFM intensities could be easily separated using polarisation analysis. A comparison of the σσ and σπ polarisations of the (0,1/2,3/2) reflection suggests that the quadrupole-quadrupole interactions are driving the onset antiferromagnetism. Furthermore, the width of the magnetic scattering was found to be broader than that of the quadrupole. in TmGa 3 , perhaps by the quadrupole coupling.

We report the direct measurement of antiferromagnetic spin polarization at the oxygen sites in the multiferroic TbMn2O5, through resonant soft x-ray magnetic scattering. This supports recent theoretical models suggesting that the oxygen spin polarization is key to the magnetoelectric coupling mechanism. The spin polarization is observed through a resonantly enhanced diffraction signal at the oxygen K edge at the commensurate antiferromagnetic wave vector. Using the fdmnes code we have accurately reproduced the experimental data. We have established that the resonance arises through the spin polarization on the oxygen sites hybridized with the square based pyramid Mn3+ ions. Furthermore we have discovered that the position of the Mn3+ ion directly influences the oxygen spin polarization.

The magnetic structures which endow TbMnO$_3$ with its multiferroic properties have been reassessed on the basis of a comprehensive soft x-ray resonant scattering (XRS) study. The selectivity of XRS facilitated separation of the various contributions (Mn $L_2$ edge, Mn 3d moments; Tb M$_4$ edge, Tb 4f moments), while its variation with azimuth provided information on the moment direction of distinct Fourier components. When the data are combined with a detailed group theory analysis, a new picture emerges of the ferroelectric transition at 28 K. Instead of being driven by the transition from a collinear to a non-collinear magnetic structure, as has previously been supposed, it is shown to occur between two non-collinear structures., Submitted to Physical Review Letters

We have studied the temperature dependences of the so-called charge and orbital ordering reflections in the neighborhood of the Verwey transition by means of resonant x-ray scattering at the Fe K and L edges on a high purity single crystal of magnetite. Contrary to recently published results [J. E. Lorenzo, Phys. Rev. Lett. 101, 226401 (2008)10.1103/PhysRevLett.101.226401], we show that all the reflections studied disappear simultaneously at the Verwey transition for both edges, on and off resonance. This means that there is no correlation between the Verwey (123.5 K) and the spin-reorientation (130 K) transitions and that the resonant reflections are driven by the lattice distortions.

Soft X-ray resonant scattering (XRS) has been used to observe directly, for the first time, the ordering of localized electronic states on both the Mn and Tb sites in multiferroic TbMnO$_3$. Large resonant enhancement of the X-ray scattering cross-section were observed when the incident photon energy was tuned to either the Mn $L$ or Tb $M$ edges which provide information on the Mn 3d and Tb $4f$ electronic states, respectively. The temperature dependence of the XRS signal establishes, in a model independent way, that in the high-temperature phase (28 K $\leq$ T $\leq$ 42 K) the Mn 3d sublattices displays long-range order. The Tb $4f$ sublattices are found to order only on entering the combined ferroelectric/magnetic state below 28 K. Our results are discussed with respect to recent hard XRS experiments (sensitive to spatially extended orbitals) and neutron scattering., Comment: 9 pages, paper has been accepted for publication in Journal of Physics: Condensed Matter as a fast track communication

Magnetite, Fe$_3$O$_4$, displays a highly complex low temperature crystal structure that may be charge and orbitally ordered. Many of the recent experimental claims of such ordering rely on resonant soft x-ray diffraction at the oxygen K and iron L edges. We have re-examined this system and undertaken soft x-ray diffraction experiments on a high-quality single crystal. Contrary to previous claims in the literature, we show that the intensity observed at the Bragg forbidden (001/2)$_c$ reflection can be explained purely in terms of the low-temperature structural displacements around the resonant atoms. This does not necessarily mean that magnetite is not charge or orbitally ordered, but rather that the present sensitivity of resonant soft x-ray experiments does not allow conclusive demonstration of such ordering., Comment: 5 pages, 3 figures

Spin-density-wave (SDW) magnetism in a series of Cr/V heterostructures with different Cr thicknesses was systematically investigated by combined resistivity, neutron, and synchrotron scattering measurements. We show that the onset of the bulklike SDW state comes through several necessary steps from a paramagnetic state through a commensurate SDW to an incommensurate SDW. The Neel temperature for the incommensurate SDW is found to scale with Cr thickness and reaches the bulk value at a Cr thickness of about 2000 A. The proximity effect from Cr/V interfaces is found to lead to (i) the appearance of a 50-A magnetically dead Cr layer near Cr/V interfaces and (ii) suppression of the spin-flip transition and stabilization of a single-domain SDW with out-of-plane spins and out-of-plane propagation wave vector. Finally, we show that the SDW period increases with decreasing Cr thickness and becomes temperature independent in sufficiently thin Cr layers.

A novel insert was developed for top‐loading liquid helium cryostats that allows a combined ±90°sample tilt with a full 360° azimuthal rotation. This sample stick is operational down to 1.5 K and was primarily designed for X‐ray scattering in reflecting geometry. The device not being intended for scanning but positioning purposes, motion precision, resolution and repeatability specifications were relaxed to 0.1°and readily achieved. This setup was initially designed for a specific cryostat and implemented at beamline ID20 of the ESRF but it can be easily adapted to similar top loading cryostats including cryomagnets. Initial results on the low temperature phases of CeB6 are presented.

A magnetic Bragg reflection corresponding to the wave vector ${\mathbf{k}}_{13}=(2\ensuremath{\pi}∕a)[\frac{1}{2},\frac{1}{2},\frac{1}{2}]$ of the antiferro-quadrupolar ordering in $\mathrm{Ce}{\mathrm{B}}_{6}$ is found without external magnetic field below the N\'eel temperature ${T}_{N}\ensuremath{\approx}2.4\phantom{\rule{0.3em}{0ex}}\mathrm{K}$. Its intensity is two orders of magnitude weaker than those due to the basic magnetic structure. The peak has a width of the other Bragg reflections below ${T}_{N}$, but widens abruptly at $T={T}_{N}$ with the simultaneous increase of intensity. The correlation length of the antiferromagnetic fluctuations just above ${T}_{N}$ is of the order of $10\phantom{\rule{0.3em}{0ex}}\mathrm{\AA{}}$. The peak intensity decreases to zero at $T\ensuremath{\approx}7\phantom{\rule{0.3em}{0ex}}\mathrm{K}$ with no visible anomaly at the antiferroquadrupolar-ordering temperature ${T}_{Q}\ensuremath{\approx}3.3\phantom{\rule{0.3em}{0ex}}\mathrm{K}$. The features of the magnetic peak $(\frac{1}{2},\frac{1}{2},\frac{1}{2})$ are typical for the itinerant magnetism. Interacting multipole moments may also give a contribution to this peak.

Coherent X-ray diffraction experiments have been performed on high quality crystals of the charge density wave (CDW) system Ko 0.3 MoO 3 . Regular fringes have been observed which are consistent with the presence of a single CDW dislocation. This dislocation is a screw-like dislocation which runs along chains axis and with a Burgers vector parallel to the CDW modulation. This first measurement confirms the presence of CDW dislocation embedded in the bulk in CDW systems and could throw light on the role of such topological defects in conversion processes of normal electrons in condensed electrons.

Coherent x-ray diffraction experiments have been performed on high quality crystals of the charge density wave (CDW) system K0.3MoO3. The satellite reflections associated with the CDW have been measured as a function of the 20-microm-diameter beam position. For some positions, regular fringes have been observed. We show that this observation is consistent with the presence of a single CDW dislocation. Beyond charge density wave systems, this experiment shows that coherent x-ray diffraction is a suitable tool to probe topological defects embedded in the bulk.

We present a study of the prototypical NiO(111) antiferromagnet by nonresonant surface x-ray magnetic scattering. Direct access to the antiferromagnetic surface and bulk spin ordering is demonstrated. Our data support a first order antiferromagnetic to paramagnetic transition. A quantitative determination of the magnetization profile is proposed. It is shown that the NiO(111) surface spins remain ordered at higher temperatures than in the bulk and that the blocking temperature in exchange coupled ferromagnetic-NiO interfaces is most likely related to an S-domain structure loss occurring 25 K below the Ne el temperature.

Direct evidence of the spatial ordering of Dy $4f$ quadrupole and hexadecapole moments in ${\mathrm{DyB}}_{2}{\mathrm{C}}_{2}$ is demonstrated by resonant x-ray diffraction enhanced by an electric quadrupole event $(E2$ resonance) at the Dy ${L}_{\mathrm{III}}$ absorption edge. The diffraction data show that the structural phase transition at ${T}_{\mathrm{Q}}=24.7\mathrm{K}$ is accompanied by a reduction in the symmetry of the Dy site to $2/m,$ from $4/m,$ and the spatial ordering of the time-even Dy multipoles with ${A}_{g}$ character. Below ${T}_{\mathrm{Q}}$ the crystal structure is described by the space group ${P4}_{2}/mnm$ and Dy ions occupy sites $(4c).$ The distortion at ${T}_{\mathrm{Q}}$ involves the lattice occupied by B and C ions, and it amounts to a buckling of B-C planes that are normal to the two-fold rotation axis of $2/m.$ An immediately plausible model of low-energy Dy states correlates data on the specific heat, our x-ray diffraction signals, and magnetic ordering below 15.3 K which has been observed in magnetic neutron diffraction.

We report on the study of the dynamics of long wavelength phason fluctuations in the i-AlPdMn icosahedral phase using coherent x-ray scattering. When measured with a coherent x-ray beam, the diffuse intensity due to phasons presents strong fluctuations or speckles pattern. From room temperature to 500 degrees C the speckle pattern is time independent. At 650 degrees C the time correlation of the speckle pattern exhibits an exponential time decay, from which a characteristic time tau is extracted. We find that tau is proportional to the square of the phason wavelength, which demonstrates that phasons are collective diffusive modes in quasicrystals, in agreement with theoretical predictions.

The magnetic ordering in CeLu alloys has been studied using neutron diffraction, and the electronic state of the Ce has been determined using X-ray magnetic resonant scattering (XMRS). CeLu orders with the same magnetic structure as Ce Y, but the temperature dependence of the order parameter is different and the average saturated moment on the Ce sites is lower. The diffuse neutron magnetic scattering observed in other Ce alloys is not observed for CeLu, and this implies that this unusual scattering originates from the competition between exchange and dipolar interactions. The XMRS results show that the Ce in CeLu alloys has an inter- mediate valence, and the results suggest that this behaviour is due to chemical pressure.

We report coherent x-ray scattering studies of charge and orbital domains in manganite systems. The experiments were carried out on LaMnO_3 and Pr_{0.6}Ca_{0.4}MnO_3, with the incident photon energy tuned near the Mn K edge. At room temperature, the orbital speckle pattern of LaMnO_3 was observed to be constant over a timescale of at least minutes, which is indicative of static orbital domains on this timescale. For Pr_{0.6}Ca_{0.4}MnO_3, both charge and orbital speckle patterns were observed. The observation of the latter rules out the presence of fast orbital fluctuations, while long time series data-- on the order of several minutes-- were suggestive of slow dynamic behavior. In contrast, the charge order speckle patterns were static., Comment: 6 pages, 4 figures

Quadrupolar ordering in a 5f electron system has been observed directly for the first time, using x-ray scattering techniques. In UPd (3) at low temperatures satellite peaks appear at (1,0,l) (orthorhombic notation) with l odd and even. Both sets of peaks show a resonant enhancement of the scattering at the M(IV) edge of U. At resonance, the dominant scattering of the l odd peaks occurs in the unrotated polarization channel, whereas for l even a significant rotated component is found. These results are discussed in terms of possible structures of the antiferroquadrupolar phases.

The magnetism of a DHCP Ho-Ce alloy has been investigated using X-ray magnetic resonant scattering. A self-consistent magnetic structure is proposed that agrees with diffraction data for three different cross sections (neutron, dipolar and quadrupolar). The spectroscopic valence of the Ce is found to be 3.27(5), and the Ce is in an intermediate-valence state in this alloy. © 2001 Elsevier Science B.V. All rights reserved.

K-edge resonant x-ray magnetic scattering experiments have been performed on antiferromagnetic NiO. The observation of two resonances at the K edge allows the construction of models to compare the electronic properties of NiO and the observed resonant magnetic x-ray scattering. From the polarization analysis of the scattered beam, a quadrupolar transition $(1s\ensuremath{-}3d)$ and a dipolar transition $(1s\ensuremath{-}4p)$ are identified. While the quadrupolar transition can be modeled using an atomic picture for the $3d$ electrons, the dipolar transition is associated to a broadband structure of p electrons and its energy profile is compared to electronic band-structure calculations.

The magnetic ordering in Ho x Ce 1− x alloys has been investigated by neutron diffraction and X-ray magnetic resonant scattering (XMRS). The DHCP alloys display a rich phase diagram, and highly unusual, diffuse neutron magnetic scattering is observed over the composition range 0.35⩽ x ⩽0.5. The diffuse intensity may be the magnetic response of the conduction band, and this interpretation is supported by the XMRS measurements, which show that there is hybridisation of the Ce 4f electron with the conduction electrons.

Among the materials exhibiting metal–insulator transition , vanadium sesquioxide V 2 O 3 and its Cr-alloys have received most attention from the theoretical and experimental point of view. It is now widely agreed that the unusual magnetic properties can be explained by taking both orbital and spin degrees of freedom into account. Whereas many experiments give direct information on the magnetic structure, only indirect evidence suggests the existence of orbital order in cases like V 2 O 3 , where it is not accompanied by cooperative Jahn–Teller distortion. We have demonstrated the existence of orbital ordering in V 2 O 3 by means of X-ray resonant scattering at the vanadium K -edge using tunable synchrotron radiation. The observed orbital structure confirms the interplay between orbital and magnetic order, and provides an illustration of a new experimental method to extract information on the electronic orbital occupancy in solids.

We present high-pressure resistivity and resonant magnetic X-ray diffraction results on single crystals of the system Ce(Fe1−xCox)2 with x = 0.07 and 0.1 where cobalt doping stabilises an antiferromagnetic phase at low temperatures. We show that on the x = 0.07 compound the effect of pressure is to increase the Neel temperature whereas in the x = 0.1 system TN decreases with applied pressure. These results show that there is a qualitative equivalence between the effects of pressure and cobalt doping in this system.

International audience; We present a method to determine the magnetic configuration of an in-plane magnetized permalloy layer using Fourier transform holography with extended references in an off-normal geometry. We use a narrow slit as an extended holographic reference to record holograms with the sample surface orthogonal to the incident x-ray beam, as well as rotated by 30° and 45° with respect to the beam. To demonstrate the sensitivity of the technique to in-plane magnetization, we present images of flux closed ground states in thin (∼50 nm) permalloy elements, less than 1 μm in lateral size. Images of the in-plane domain pattern which is magnetostatically imprinted into a permalloy film by the stray fields generated by an adjacent Co/Pt multilayer were obtained. It is found that, whilst the domain patterns within the two magnetic layers show a strong resemblance at remanence within a pristine sample, the similarities disappear after the sample is exposed to a saturating magnetic field.

We report here soft resonant x-ray scattering (SRXS) measurements on a single crystal of highly stoichiometric Fe3O4 (Verwey transition at Tv = 123.5 K). Resonant intensity was observed at the Fe L2,3 and the O K edges for the (0,0,1/2) reflection and at the Fe L1-edge for the (001) reflection in the low temperature phase. The energy, azimuthal angle and temperature dependence was explored using either σ- or π-incidence. The (001) reflection is active in the σ-σ' polarization channel whereas the (0,0,1/2) reflection is in the σ-π' polarization one. The (0,0,1) reflection is also observed at energies below the Fe L1-edge, confirming that this reflection is permitted by the crystal symmetry of the low temperature phase. On the other hand, the (0,0,1/2) reflection is strictly forbidden and scattered intensity is only observed on resonance. The resonant and non-resonant signals simultaneously disappear at TV for the two studied reflections at both the Fe L-edges and the O K-edge. This result indicates that the resonant reflections and the associated electronic anisotropy of the Fe d, Fe p and O p-states are explained by the lattice distortions.

The magnetic ordering in Ce-Y alloys has been investigated using neutron diffraction and X-ray magnetic resonant scattering (XMRS). Neutron diffraction determined the magnetic structure to be antiferromagnetic with magnetic modulation vector [1/2, 0,0] and with moments pointing perpendicular to this direction in the basal plane. XMRS studies revealed that Ce-Y forms an ideal system with the localised 4f electrons characteristic of the other lanthanides. © 2001 Elsevier Science B.V. All rights reserved.