REXS 2025 Almadraba

6 Oct 2025, 08:15 → 10 Oct 2025, 16:00 Europe/Madrid

Hotel Almadraba Park (Roses, Girona, Spain)

Gloria Subias-Peruga (INMA, CSIC-Universidad de Zaragoza), Javier Herrero Martin, Daniel Pérez Salinas, Pierluigi Gargiani (Alba Synchrotron Light Source), Manuel Valvidares

International Conference on Resonant Elastic X-ray Scattering

The International Conference on Resonant Elastic X-ray Scattering, REXS 2025 Almadraba, continues the tradition of a key gathering for researchers exploring advanced resonant x-ray synchrotron techniques to investigate the structural, electronic, and magnetic properties of matter. This 2025 edition unfolds as a truly inspiring experience where science will blend in harmony with local culture and the beauty of earth and oceanic natures.

The local organizing and international scientific committees have put great effort and enthusiasm into crafting an outstanding and timely scientific program, set against the backdrop of a stunning location and a serene, welcoming atmosphere, ensuring both intellectual engagement and relaxation. 

We sincerely hope that this event will be an inspirational source for exciting new ideas, and an opportunity to foster fruitful collaborations and strengthen professional relationships. For younger researchers, it presents a valuable opportunity to acquire new skills, deepen scientific insights, and expand resources for their career development—all at the verge of a natural environment designed to inspire.

We look forward to welcoming you to REXS 2025 Almadraba, where scientific excellence meets the charm of an unforgettable setting,

The local organising and international scientific committees.

CONFERENCE ORGANIZATION ASSISTANCE AGENCY

 

SPONSORS

ADDITIONAL FINANCIAL SUPPORT ACKNOWLEDGEMENTS

• ALBA Synchrotron Light Source and the ALBA Experiments Division. Special thanks to the facility director Dr. Caterina Biscari and Dr. Klaus Attenkofer, head of the Experiments Division for their support.
• Instituto de Nanociencia y Materiales de Aragón, INMA, CSIC-Unizar
• AUSE, Spanish Synchrotron Users Association
• MICIN/AEI GRANT STEMIN2D PID2023-146354NB-C43

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Monday, 6 October

08:15 → 09:00 Registration

09:00 → 12:30 Tutorials + coffee break

09:00 Welcome and Introduction to the Tutorials

09:30 Circular Dichroism in Resonant Elastic X-ray Scattering-I

Speaker: Prof. Shilei Zhang (ShanghaiTech University)

09:30 Simulation Of REXS With FDMNES -I

Speaker: Prof. Yves Joly (Institut Néel, CNRS)

10:50 Coffee Break

11:10 Circular Dichroism in Resonant Elastic X-ray Scattering-II

Speaker: Prof. Shilei Zhang (ShanghaiTech University)

11:10 Simulation Of REXS With FDMNES -II

Speaker: Yves Joly (Institut Néel, CNRS)

12:30 → 14:00 Lunch break

14:00 → 16:00 Opening session

14:00 Welcome REXS2025

REXS 2025 local chairs and int.comm. chair
ALBA management (research director)

Speaker: Klaus Attenkofer

14:30 REXS Opening Keynote talk : REXS: a Journey Across Space and Time

Speaker: Dr Claudio Mazzoli (Brookhaven National Laboratory)

15:10 EXPERIMENTAL HALL VISIT

16:30 → 18:30 Bus to hotel / Workshop venue

18:30 → 19:30 Arrival at hotel, Registration

19:30 → 20:00 Cocktail

20:00 → 21:00 Dinner

Tuesday, 7 October

09:00 → 12:15 Talks Tuesday Morning

09:00 Keynote talk - tittle to be determined

Speaker: Prof. Paolo Radaelli (Oxford University)

09:35 Imprinted emergent textures in amorphous rare-earth transition-metal ferrimagnets

Amorphous rare-earth transition-metal (RE-TM) ferrimagnets are workhorse materials in the field of spintronics. Developed chiefly for magneto-optical recording and bubble memories in the second half of the 20th century, they have remained at the forefront of the field, for example because they allow for ultrafast all-optical switching1, ultrafast current-driven domain wall motion2, and easy, gradual tuning from ferromagnetic to antiferromagnetic behavior. However, these materials are also known to exhibit chemical heterogeneity, both laterally3 and in thickness direction4, as well as sperimagnetism5, i.e., intrinsically non-collinear alignment of spins. So far, these effects were largely ignored in spintronics research.
Here, we report on the discovery of emergent textures in the structure of amorphous RE-TM ferrimagnets (Fig. 1), which are imprints the magnetic domains walls of the as-grown state and can be traced back to long-range-ordered patterns of chemical heterogeneity and sperimagnetism. The nature and implications of these imprinted emergent textures are revealed by resonant x-ray scattering and imaging experiments, in concert with advanced transmission electron microscopy and scanning probe microscopy, as discussed in this talk.

Speaker: Felix Buettner (Helmholtz-Zentrum Berlin & University of Augsburg)

10:00 SoftiMAX-CXI: A new soft x-ray branch for scattering and diffraction methods at MAX IV

Speaker: Jörg Schwenke (MAX IV Laboratory / Lund University)

10:25 Coffee Break

10:50 Beyond the Surface: 3D Probing of Antiferromagnets — A Journey Through Failures and Breakthroughs

Speaker: Valerio Scagnoli (ETHZ - PSI)

11:25 Controlling Skyrmion Lattice Dynamics with Thermal and Magnetic Field Gradients

Magnetic skyrmions exhibit a rich landscape of dynamical behavior shaped by their topological character and collective organization. In this work, we explore the motion of skyrmion lattices in chiral magnets under two orthogonal driving mechanisms: magnetic field gradients [1] and thermal gradients [2,3]. Using resonant elastic x-ray scattering (REXS) on Cu$_2$OSeO$_3$, we demonstrate how finite-sized skyrmion lattices respond to these drives not only by translation, but also by rotation, undergoing a coherent rolling motion driven either by magnon flow (in thermal gradients) [2] or by field-induced torques [1]. The rotational sense and velocity scale predictably with gradient strength and crystallite size, revealing the emergence of a chiral lattice torque, also allowing for the direct measurement of the skyrmion Hall angle in the lattice state [4]. To access the three-dimensional nature of skyrmion textures, we complement these surface-sensitive studies with small-angle neutron scattering (SANS) experiments on MnSi [3]. There, we uncover depth-resolved bending of skyrmion strings under two-dimensional thermal gradients, driven by a temperature-dependent skyrmion Hall effect and governed by a modified Thiele equation incorporating magnon friction. This dual approach, combining high-resolution REXS at the surface and SANS through the bulk, offers a unified view of skyrmion lattice dynamics and demonstrates new modalities for manipulating topological spin textures in three dimensions.

Speaker: Thorsten Hesjedal (University of Oxford)

11:50 From π-CSL to fan: a topological phase transition in one dimension

Speaker: Moritz Winter (Max Planck Institute for Chemical Physics of Solids and TU Dresden)

12:15 → 14:15 Lunch break

14:15 → 17:25 Talks Tuesday Afternoon

14:15 Advancing the Sample Space to Elevate the Power of Resonant X-ray Scattering.

Deploying in-situ strain with electrical multi-modal x-ray scattering measurements has allowed for powerful experimental configurations deepening our understanding of complex quantum phenomena. Touching upon a few recent topics e.g., nematic behavior in Fe superconductors (1-4) and quantum paraelectric behavior in SrTO3 membranes (5) I’ll demonstrate the value-added power of investing in the sample space and overview our plans to explore dopant-vacancy color center qubit behavior with symmetry and strain combining photoluminescent spectroscopy and x-ray scattering.

The ability to measure and control structure, symmetry or domain population of a twinned system, like an orthorhombic crystal or magnetic orientated domains can be a critical sample control parameter to study intricate quantum behaviors. In the iron based superconductor, electronic nematicity is coupled to both the lattice and the conducting electrons leading to both structural and transport measurements sensitive to nematic fluctuations. While spin driven nematicity is prevalent in Fe pnictides, the role of spin versus orbit in the chalcogenide nematic behavior has been under investigation. The consortium of electrical and x-ray scattering measurements keenly addresses the relationship of lattice, spin and orbital order in the nematic phase space. SrTO3 is a ubiquitous prototype material but is itself an intriguing enigmatic host of quantum behaviors, using strain as a tuning parameter we investigate the transition from classical to quantum behaviors and consider the unbounded potential studies deploying this combination of strained single crystal membranes with resonant x-ray scattering.

1. Strain-Switchable Field-Induced Superconductivity, Joshua J. Sanchez, Gilberto Fabbris, Yongseong Choi, Jonathan M. DeStefano, Elliott Rosenberg, Yue Shi, Paul Malinowski, Yina Huang, Igor I. Mazin, Jong-Woo Kim, Jiun-Haw Chu, Philip J. Ryan*, Science Advances 9, eadj5200(2023). DOI:10.1126/sciadv.adj5200 Incommensurate
2. Suppression of superconductivity by anisotropic strain near a nematic quantum critical point, P. Malinowski, Q Jiang, JJ Sanchez, J Mutch, Z Liu, P Went, J Liu, P.J. Ryan, JW Kim, Jiun-Haw Chu, Nature Physics, 1-5, (2020)
3. Spontaneous orbital polarization in the nematic phase of FeSe. Connor A. Occhialini, Joshua J. Sanchez, Qian Song, Gilberto Fabbris, Yongseong Choi, Jong-Woo Kim, Philip J. Ryan and Riccardo Comin, Nature Materials 22, 985 (2023). doi:10.1038/s41563-023-01585-2
4. Joshua J. Sanchez, Paul Malinowski, Joshua Mutch, Jian Liu, J.-W. Kim, Philip J. Ryan, Jiun-Haw Chu, The transport–structural correspondence across the nematic phase transition probed by elasto X-ray diffraction. Nat. Mater. (2021). https://doi.org/10.1038/s41563-021-01082-4
5. Li, J., Lee, Y., Choi, Y. et al. The classical-to-quantum crossover in the strain-induced ferroelectric transition in SrTiO3 membranes. Nat Commun 16, 4445 (2025).

Speaker: Philip Ryan (Argonne National Laboratory)

14:40 Structural and Magnetic Chirality In NiCo2TeO6

A. Bombardi [1], N. Qureshi [2], A. Vibhakar [1], K. Beauvois [3], R. Scatena [1], F. Carneiro [1], C. J. Won [4] and S.-W. Cheong [5]
[1] Diamond Light Source, Harwell Science and Innovation Campus Didcot OX11 0DE, Oxfordshire, UK
[2] Institut Laue-Langevin, 71 avenue des Martyrs, CS 20156, 38042 Grenoble Cedex 9, France
[3] Université Grenoble Alpes, CEA, IRIG, MEM, MDN, 38000 Grenoble, France
[4] Laboratory for Pohang Emergent Materials and Max Planck POSTECH Center for Complex Phase Materials, Pohang Univ. of Science and Technology, Dept. Phys., Pohang, Korea
[5] Rutgers Center for Emergent Materials and Department of Physics and Astronomy,
Rutgers University, Piscataway, NJ, 08854, USA

ABSTRACT

The chiral nature of our immediate environment is obvious to us structurally and functionally, and it seems to be a key ingredient of life, yet it remains one of the most elusive properties to understand and investigate at the atomic length scale.
X-rays measure structural chirality via the interference of the anomalous scattering factor. This provides a tiny variation in the measured intensity, usually sufficient to distinguish between different enantiomers, whereas both non-resonant and resonant magnetic scattering can be used to assess inversion domains in non collinear magnetic structure via the helicity of the probe, see [1] and references therein. The case of neutrons is similar, with polarized neutrons able to assess magnetic chirality and inversion domains [1], whereas the tiny relativistic Schwinger term is the only cross section term to measure the structural chirality [1].
Here, we present a combined X-ray and polarized neutron scattering study on chiral, polar and magnetoelectric compound NiCo2TeO6[2,3]. This system adopts a structural arrangement derived from the corundum R3c of Al2O3, but the introduction of Co and Te at the Al site breaks the inversion and the c-glide symmetry, generating a ferri-chiral structural arrangements, with often both chirality present in the same crystal.
Using a similar methodology to the one adopted in the case of Ba3NbFe3Si2O14 [1], we determine the relation between the magnetic and structural chirality in this system.
A clear theoretical framework of the microscopic interactions driving the chirality of NiCo2TeO6 is still missing, but our experimental results provide a sound foundation to understand the origin of this phenomenon and to future application of the magnetoelectric properties of this system.
REFERENCES
1. N. Qureshi et al. Phys. Rev. B 102, 054417 (2020).
2. X. Wang et al. APL Mater. 3, 076105 (2015).
3. N. Qureshi et al. to be submitted to Phys Rev B

Speakers: Alessandro Bombardi (Diamond Light Source), Dr Rebecca Scatena (Diamond Light Source)

15:05 Dispersion-Induced Pseudo-Extinction of the Bragg Reflection and the Magnetic Asymmetry in REXS from Ferromagnets

Speaker: H Adachi

15:30 Uniaxial Pressure Control of Charge Density Wave in ScV6Sn6

Uniaxial Pressure Control of Charge Density Wave in ScV6Sn6

Fellipe B. Carneiro (1), Eduardo M. Bittar (2), Priscila Rosa (3) and Sean M. Thomas (3).

(1) Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot, Oxfordshire, UK.

(2) Centro Brasileiro de Pesquisas Fisicas, 22290-180, Rio de Janeiro, RJ, Brazil.

(3) Los Alamos National Laboratory, Los Alamos New Mexico, USA.

ScV6Sn6 is a bi-layer Kagome system in which the structural degrees of freedom in the out-of-plane direction are suggested to play a major role in the stabilization of the charge density wave (CDW) order [1-3]. Here, we investigate the effects of uniaxial pressure along the c axis in this material. Our electrical resistivity measurements under c-axis uniaxial stress reveal a fast suppression of the CDW transition followed by a change in the CDW character at 0.9 GPa. In contrast, our x-ray diffraction measurements show that at near-zero stress, CDW reflections are initially enhanced by c-axis compression, with suppression occurring beyond 0.05 GPa. Our findings highlight the importance of the c-axis lattice parameter for the tuning and stabilization of the CDW order in this material.

1. W. S. Arachchige, W. R. Meier, M. Marshall, T. Matsuoka, R. Xue, M. A. McGuire, R. P. Hermann, H. Cao, and D. Mandrus, Charge Density Wave in Kagome Lattice Intermetallic ScV6Sn6, Phys. Rev. Lett. 129, 216402 (2022).

2. K. Wang, S. Chen, S.-W. Kim, and B. Monserrat, Origin of competing charge density waves in Kagome metal ScV6Sn6, Nat. Commun. 15, 10428 (2024).

3. G. Pokharel, B. R. Ortiz, L. Kautzsch, S. J. Gomez Alvarado, K. Mallayya, G. Wu, E.-A. Kim, J. P. C. Ruff, S. Sarker, and S. D. Wilson, Frustrated Charge Order and Cooperative Distortions in ScV6Sn6, Phys. Rev. Materials 7, 104201 (2023).

Speaker: Fellipe Carneiro (Diamond Light Source)

15:50 Break

16:10 XMaS, The UK Materials Science Beamline At The ESRF

XMaS/BM28 is a UK-National Research Facility funded by EPSRC and located at the ESRF, the European Synchrotron in Grenoble (France). The project is jointly managed by the Universities of Warwick and Liverpool. The beamline has been supporting UK materials scientists since 1997 in a wide range of disciplines spanning physics, chemistry, environmental sciences, materials and engineering but also medicine and cultural heritage.
XMaS was originally designed for the exploration of magnetic materials using scattering techniques that remains a core activity of the facility, benefiting from a large suite of sample environments available on the beamline (e.g. low/high temperatures, magnetic and electric fields …). The recent facility upgrade has extended the energy spectrum of the facility from 2.035 keV up to 47 keV thus opening new opportunities for studies at the L-edges of 4d-transition metals and K-edges of light rare-earths (e.g. Sm, Nd …).
In addition to the main synchrotron beamline, XMaS also provides access to two offline laboratories. The first one, equipped with a Cu micro-source and a 4-circle Huber diffractometer, is optimized for diffraction and reflectometry studies using a 2D MAXIPIX detector. The second one is used to perform electrical characterization as a function of temperature (2 - 800 K) and applied magnetic fields (up to 4 T).
Some case studies will be presented to illustrate the capabilities of the beamline. More highlights can be found in our annual Newsletter1. A complete description of the beamline is available at www.xmas.ac.uk. One can also follow us on the social media X (@XMaSBeam) or contact us directly at xmas@esrf.fr.

REFERENCES
1. www.xmas.ac.uk/impact/newsletters/

Speaker: Didier Wermeille

16:35 Molecular and Electronic Structure at Electrochemical Interfaces from In Situ Resonant X-Ray Diffraction

In electrocatalysis, reactivities are crucially affected by the structure at the electrochemical interface, the few Å thick region at the metal-liquid interface. A precise understanding of the charge and molecular distribution is a mandatory step for the comprehension of the underlying mechanisms. Nevertheless, up to now direct experimental methods probing electronic/molecular structure at the atomistic level in the electrochemical interface were lacking.
We recently proposed an original method [1,2] coupling in situ Surface Resonant X-Ray Diffraction (SRXRD) to DFT calculations. Following the Helmholtz description, we modelled the interface as a double layer, where an ionic plane in the liquid phase faces the oppositely charged metal surface.
After a preliminary attempt [3], allowing only a semi-quantitative description of the charge distribution at the interface, we have now introduced a realistic physical model [1] which gives access quantitatively to the molecular and electronic structure both in the crystal surface layers and in the close solution. The ionic layer is here described by chemically defined ions/molecules set in front of the metal. Their occupation rate, charge, position and Debye Waller factor are the parameters we have to solve by comparison with SRXRD spectra, thanks to a confidence factor. Because our system is neutral and our simulations are self-consistent, we also obtain the atomic charge distribution in the crystal surface layers.
We successfully applied our method to the archetypal Pt(111) system in an acidic medium, focusing on the potential region where no adsorbates are present. In situ SRXRD measurements were made at the D2AM beamline (ESRF, Grenoble). The spectra were recorded at several reciprocal space positions and with different orientations of the polarization to probe the chemical bonds in and out of the surface plane.
Contrarily to the typical assumption of zero free charge on the Pt metal surface at this potential, our experimental data clearly reveal the presence of partially ordered water molecules and hydronium ions close to the negatively charged metal surface, signature of a significant interaction between the metal and water.
We believe that our original approach will significantly contribute to bridging the knowledge gaps surrounding electrocatalytic mechanisms comprehension and will be instrumental in enhancing theoretical predictions, which have lacked data from physical characterization techniques.

1. Y. Soldo-Olivier, Y. Joly, M. De Santis, Y. Gründer, N. Blanc and E.Sibert, JACS 147(6), 5106 (2025)
2. Y. Gründer; C. Lucas, P. Thompson, Y. Joly and Y. Soldo-Olivier, J. Phys. Chem C 126, 4612 (2022)
3. Y. Soldo-Olivier, E. Sibert, M. De Santis, Y. Joly and Y. Gründer, ACS Catalysis 12, 2375 (2022)

Speaker: yvonne soldo (Institut Néel - CNRS)

17:00 MagStREXS: Magnetic Structures Through Resonant Elastic X-ray Scattering

Speaker: Dr Pablo J. Bereciartua (Deutsches Elektronen-Synchrotron DESY)

17:25 → 17:45 Free time

17:45 → 19:15 Poster session Tuesday

17:45 Controlling Spin Periodicity in a Helical Heisenberg Antiferromagnet

Speaker: Hyein Jung (Technical University Berlin / Fritz Haber Institute of the Max Planck Society)

17:45 Looking for Magnetoelectricity in Single-Phase Multiferroic Oxides using RMXS

Speakers: Dr Javier Herrero-Martin, José Luis García-Muñoz (Institut de Ciència de Materials de Barcelona -CSIC)

17:45 Many-Body Interactions in Room-Temperature Van der Waals Magnet Fe5GeTe2

The complex ground states of recently discovered two-dimensional (2D) magnets with Curie temperatures near room temperature present exciting opportunities for functional spintronic devices, but remain poorly understood. We investigate the electronic and magnetic excitations in the van der Waals ferromagnet Fe5GeTe2 (Tc=300K) using angle-resolved photoemission spectroscopy (ARPES) and resonant inelastic X-ray scattering (RIXS). ARPES measurements reveal a pronounced kink in the band dispersion below the Curie temperature, indicating strong many-body interactions. Complementary RIXS spectra exhibit multiple energy loss features and point to electron-magnon coupling. These findings highlight the interplay between electronic structure and magnetic excitations in Fe5GeTe2 and its potential in room-temperature 2D spintronic applications.

Speaker: Dr Khadiza Ali (Lund University)

17:45 PolSpecX: Simulation and Analysis Tool for Polarised X-Ray Absorption Spectroscopy

PolSpecX [1] is an integrated software tool designed for the simulation and analysis of X-ray magnetic circular dichroism (XMCD) and X-ray magnetic linear dichroism (XMLD) spectra of 3d transition metal elements at the L₂ and L₃ absorption edges. Leveraging the capabilities of Quanty [2-4] for multiplet calculations, PolSpecX enables accurate theoretical modelling of dichroic spectra under various electronic and magnetic configurations. In parallel, the tool provides a robust framework for the analysis of experimental data acquired from the magnetic materials beamlines at Diamond Light Source [5], or in principle any beamline using the NeXus file definition. Key features include automated subtraction of polarized spectra, background correction, application of XMCD sum rules for quantitative magnetic moment extraction, and direct comparison between simulated and measured spectra. By bridging advanced theoretical simulations with high-quality synchrotron data analysis, PolSpecX offers a comprehensive platform for researchers investigating the electronic and magnetic properties of correlated electron systems. Such a platform will enable visiting scientists to quickly assess the quality of their data and concentrate on the scientific goals of their beamtime.

Here we will show the web-based interface, explain the user-friendly design choices and highlight some preliminary comparisons between beamline data and simulation.

Speaker: Dan Porter (Diamond Light Source)

17:45 Recent Research and Developments on the Scattering Endstation of i10 Beamline of Diamond Light Source

ABSTRACT
The Beamline for Advanced Dichroism Experiments delivers a soft X-ray beam in the 0.4–1.6 keV energy range. The availability of all polarisation states, combined with the pronounced dichroic effects characteristic of the soft X-ray regime, has facilitated advanced research on magnetism in novel nanostructured systems. The beamline features two endstations, scattering and absorption, each utilising distinct interactions between magnetic materials and incident X-rays to probe material properties.
The scattering endstation is equipped with a 2-circle diffractometer called RASOR [1]. The resonant elastic scattering measurements on RASOR range from magnetic reflectivity studies to soft X-ray diffraction probing magnetic ordering in crystals and multilayers. The scattered beam is detected either by a photodiode or one of the area detectors which may be fixed or movable. The detector arm includes a polarisation analyser which can be used with multilayers optimised for specific elemental absorption edges.
A Janis liquid helium cryostat enables measurements at sample temperatures down to 12K. A phi rotation can be added which allows rotation of the sample in situ about its surface normal. Its use, however, limits the minimum achievable sample temperatures to approximately 50K. The measurements can be performed under applied electric and magnetic fields. Various configurations of electromagnets and permanent magnets are available, providing field strengths upto 0.2T. A Halbach array is currently under commissioning which will allow in vacuum roration of the magnetic field in all three dimensions.
REFERENCES
1. T. A. W. Beale, T. P. A. Hase, T. Iida, K. Endo, P. Steadman, A. R. Marshall, S. S. Dhesi, G. van der Laan, P. D. Hatton, Rev. Sci. Instrum. 1 July 2010; 81 (7): 073904

Speaker: Paul Steadman (Diamond Light Source Ltd)

17:45 Resonant diffuse scattering in metallic VO2

Metal-Insulator transitions are among the most active topics in condensed matter physics. The electronic transition takes place concomitantly with a structural transition, making it hard to disentangle the underlying mechanism. Two scenarios are possible and are at the core of an unresolved and longstanding debate: i) the transition is driven by purely electronic interactions or ii) it is driven by electron-phonon coupling.
Using VO2 as case study, we investigated the nature of electronic and structural fluctuations within the metallic state by measuring resonant and off-resonance diffuse scattering. We found strong, pre-transitional structural fluctuations above Tc, which show no enhancement on resonance. Our results hint that structural and electronic fluctuations are strongly coupled in metallic VO2, supporting electron-phonon coupling as the driver of the metal-insulator transition.

Speaker: Javier del Valle Granda (Universidad de Oviedo)

17:45 REXS experimental stations at beamline P09 at PETRA III at DESY

At PETRA III at DESY, at beamline P09, two experimental stations are dedicated to resonant X-ray diffraction (REXS), each one equipped with different diffractometers to accomodate either light- or heavy-weight sample environments. Low temperature experiments can be performed in combination with either magnetic fields up to 14 T or high pressure until 20 GPa allowing it to investigate a diversity of long range ordered phases in strongly correlated and magnetic materials. State-of-the-art polarization control and analysis are available in a wide range of energy from 3.0 to 13.5 keV, for which dedicated data analysis pipelines are available for fast analysis of the Stokes parameters, allowing it either to disentangle between different order parameters or eventually perform full magnetic structure determinations. Hereby, I will present an update of the REXS capabilities at beamline P09 at PETRA III and some related recent highlights.

Speaker: Sonia Francoual (DESY)

17:45 Soft X-ray Coherent Magnetic Imaging of 2D van-der-Waals materials at low temperatures and under high-applied magnetic fields

Speaker: Manuel Valvidares

17:45 The Materials and Magnetism Beamline, I16 at Diamond Light Source

Speaker: Dr Aly Abdeldaim (Diamond Light Source)

17:45 udkm1Dsim – a Python toolbox for simulating 1D ultrafast dynamics in condensed matter

Speaker: Daniel Schick (Max Born Institute)

17:45 Ultrafast Diagnostics for Soft X-Ray Applications

We provide a comprehensive overview of our current line of detectors designed for soft-X-ray detection in synchrotron and laser science. We will cover a variety of detector types, including streak cameras and sCMOS cameras, highlighting their respective performance metrics, integration capabilities, and use cases in synchrotron beamlines, and laboratory setups. We also discuss recent advancements in compressed ultrafast photography (CUP), a new computational imaging technique that integrates compressed sensing with streak imaging for single-shot 2D ultrafast imaging. To prove the concept, we designed and manufactured a patterned ultraviolet photocathode and integrated it into a streak camera. This new system exhibits a sequence depth of up to 1500 frames with a size of 1750 × 500 (x, y) pixels at an imaging speed of 0.5 trillion frames per second. This system can be easily adapted to soft x-ray, showing its potential for imaging and characterization at synchrotrons.

Speaker: Dr Christian-Yves COTE (Axis Photonique Inc.)

17:45 Ultrafast dynamics of chiral spin structure in synthetic antiferromagnet

In synthetic antiferromagnetic multilayers (SAFs), chiral magnetic structures such as spin spirals and skyrmions have been stabilized at room temperature by precisely tuning the effective perpendicular magnetic anisotropy, the Dzyaloshinskii-Moriya interaction, and the Ruderman-Kittel-Kasuya-Yoshida (RKKY) interlayer coupling [1-3]. In this study, we investigate the dynamics of chiral spin spirals on ultrashort timescales after femtosecond laser pumping in SAFs. The access to ultrafast magnetization dynamics, inaccessible by standard techniques due to zero net magnetization, has been enabled by the use of time-resolved circular dichroism in x-ray resonant magnetic scattering (CD-XRMS) [4]. A pair of two-dimensional X-ray scattering patterns for left and right elliptical polarization (EL and ER) have been recorded for each delay. In contrast to our previous findings in ferromagnetic multilayers, the magnetization (EL+ER) and dichroism (EL-ER) signals exhibit notably similar ultrafast dynamics, with demagnetization occurring on a timescale of ~180 fs, followed by rapid remagnetization within ~500 fs. This similarity in ultrafast dynamics can be attributed to the continuous rotation of magnetization in the spin spiral of SAFs, which evolves smoothly in space without forming sharp domains or alternating domain walls. The ultrafast response and stability in its topological character highlight the potential of SAF-based chiral magnetic structures for future high-speed, energy-efficient data storage and processing applications.

Speaker: Zongxia GUO (Synchrotron SOLEIL)

17:45 XRMS study of stripe domains in amorphous NdCo5 thin films with an in-plane anisotropy induced by oblique angle deposition

Magnetic stripe domains have interesting properties, like unidimensional periodicity and rotatable anisotropy [1], which makes them suitable for spintronics applications like reconfigurable spin wave guides [2] or domain wall racetracks [3]. The understanding of the mechanisms that permit these kinds of applications requires a complete characterization of the magnetic stripes. X ray Resonant magnetic scattering (XRMS) seems an ideal tool for this purpose due to its sensitivity to magnetic stripe domains characteristics [4] with no restrictions of field intensities or temperature, and with enough intensity to allow magnetic stripe dynamics [5]. In this work, we present XRMS measurements of the stripe domain configuration in amorphous NdCo5 thin films, 65 nm thick, with weak perpendicular magnetic anisotropy (PMA) used as hard magnet substrate for different magnetic applications [1,2]. These thin films increase their PMA energy with film thickness, being close to the maximum value at the thickness studied. The films are deposited by magnetron sputtering with an oblique angle incidence for the Nd atoms (30°) which induces a magnetic easy axis in the plane. Several features appear in the XRMS stripe pattern of the films that are connected to their magnetic morphology: The shape of the XRMS peaks related to the periodicity of the stripes changes in width depending on the orientation of the beam with respect to the in-plane magnetic easy axis. The peaks have a small but visible transfer moment component, q, parallel to the plane of incidence which is absent in samples where the oblique incidence effect is reduced by rotating the sample during film deposition. The evolution of these features was measured as a function of the applied field. This experiment demonstrates the high sensitivity of XRMS to magnetic features that are not obvious to deduce with other magnetic moment sensitive techniques.

Speaker: Javier Ignacio Diaz Fernández (Universidad de Oviedo)

19:15 → 19:20 End of daily program

Wednesday, 8 October

09:00 → 12:15 Talks Wed Morning

09:00 Hyperspectral Imaging of Ultrafast and Nanoscale Phase Transitions in Quantum Materials

Using light to drive phase transitions in quantum materials is an emerging tool for inducing material properties “on demand” [1]. However, while we have many methods to measure the average change in material properties on the femtosecond timescale, observing the spatial dynamics of the phase transition with femtosecond time resolution has remained challenging.

In this work, I will summarize our recent work to use coherent diffractive imaging to image light-induced phase transitions in the quantum material vanadium dioxide (VO2) on the femtosecond timescale. In particular, I will show how spectrally-dependent imaging at the oxygen K and Vanadium L edges can be used to obtain contrast and identify phase transitions [2,3] and how the use of X-ray lasers enables direct measurement of the phase transition pathway [4]. In addition, I will present some unpublished work on the stability of light-induced domains and the recovery pathway for the light induced phase transition.

1. D. N. Basov, R. D. Averitt, and D. Hsieh, Nature Materials 16, 1077 (2017).
2. L. Vidas, et al, Nano. Letters 18, 3449 (2018).
3. A. S. Johnson, et al, Science Advances 7, eabf1386 (2021)
4. A. S. Johnson, et al, Nature Physics 19, 215 (2023)

Speaker: Simon Wall (Aarhus University)

09:35 Laser-driven resonant soft-X-ray scattering for probing picosecond dynamics of nanometre-scale order

Speaker: Daniel Schick (Max Born Institute)

10:00 Complementary Insights into Ultrafast Element- and Lengthscale-specific Dynamics

The properties and functionalities of solids, molecules and hybrid compounds used in modern technology is dictated by the interplay between the electronic, lattice and spin degrees of freedoms. Pump-probe techniques are ideal to selectively investigate their time evolution and disentangle complex processes. Their extension to the Extreme Ultraviolet and X-ray regime allows element specificity and the possibility to access meso- and nanoscopic length scales.
In this talk I will introduce two spectroscopy techniques aiming at accessing the mesoscopic range, inaccessible with common optical laser spectroscopies or X-ray and neutron scattering experiments. I’ll start by showing how Extreme Ultraviolet (EUV) Transient Grating spectroscopy, pioneered at the FERMI free electron laser, accesses thermo- and magnetoelastic properties of matter. Then, I’ll discuss its complementarity with the recently demonstrated extension to the hard X-ray. Finally, I will present EUV diffuse scattering as a complementary technique and address how it could potentially be performed at synchrotrons with ps time resolution.

Speaker: Laura Foglia (Elettra Sincrotrone Trieste S.c.p.A)

10:30 Coffee Break

11:00 Skyrmion Dynamics Using FMR In Resonant Elastic X-ray Scattering

See MS-word attachment

Speaker: Gerrit van der Laan (Diamond Light Source)

11:20 Ultrafast Spin-Wave Soliton Coupling To Lattice Dynamics

Spin waves are the fundamental excitations in magnetic systems. At low densities, they behave as independent quasiparticles that can mediate solid-state interactions such as superconducting pairing or can be used to transport information in technology. At sufficiently high densities, spin waves can condense into solitons that derive their stability from nonlinear spin precession. Nonequilibrium conditions via demagnetization with a femtosecond (fs) laser pulse provide an alternative generation mechanism for spin-wave solitons [1] and skyrmions [2] as seen by time-resolved soft x-ray magnetic scattering [1,2]. Spin-wave solitons nucleated in FePt nanoparticles of ~16nm size are characterized by an in-plane spin precession at the soliton boundary. We have recently shown that this spin precession perturbs the lattice by means of the magneto-elastic coupling [3]. Here we show new experiments performed at the European XFEL that identify the formation of spin-wave soliton in the smaller FePt particles with the average size of 7 nm. Such a spin-wave soliton would have the smallest size of 5 nm, and the fastest precession frequency of 0.12 THz, observed so far. This new information allows us to address the scaling of spin-wave soliton in the FePt nanoparticles, as well as the aspects of spin-lattice coupling and other related non-equilibrium magnetic phenomena in material with exchange length approaching the atomic scale.
REFERENCES
1. E. Iacocca, et al., Nat. Commun. 10, 1756 (2019).
2. F. Büttner, et al., Nat. Mater. 20, 30 (2021).
3. D. Turenne, et al., Sci. Adv. 8, eabn0523 (2022).

Speaker: Hermann Durr (Uppsala University)

11:40 Single-shot antiferromagnetic switching in exchange biased IrMn/CoGd bilayer

Ultrafast manipulation of magnetic order has challenged our understanding of the fundamental and dynamic properties of magnetic materials. Until now, single-shot magnetic switching has been limited to ferrimagnetic alloys, multilayers, and engineered ferromagnetic heterostructures [1-2]. In ferromagnetic (FM)/antiferromagnetic (AFM) bilayers, the exchange bias field (He) arises from interfacial exchange coupling and reflects the microscopic orientation of the antiferromagnet [3]. In our previous studies, we demonstrated single-shot switching of the antiferromagnet using a single femtosecond laser pulse in IrMn/CoGd bilayers (ref). We have shown that the exchange bias field can be manipulated across a wide range of laser fluences, layer thicknesses, and compositions [4]. We will show in the presentation that using element-specific circular dichroism X-ray resonant magnetic scattering (CD-XRMS), we can directly probe the depth and temperature dependence of uncompensated antiferromagnetic spins at the IrMn/CoGd interface. A time-resolved CD-XRMS experiment is scheduled at the FERMI free-electron laser facility to further investigate the ultrafast switching dynamics of Co and Mn in an element-selective manner. These dynamics are expected to reinforce our observation of ultrafast exchange bias switching. Our results present the fastest and most energy-efficient method for setting the exchange bias to date, opening new avenues for ultrafast spintronic device applications.

Speaker: Zongxia GUO (Synchrotron SOLEIL)

12:15 → 14:15 Lunch

14:15 → 17:45 Talks Wed Afternoon

14:15 Ultrafast Control of Electron-Phonon Coupling in LNSCO and LESCO

The emergence of $d$-wave superconductivity from the Mott insulating state in the cuprates is widely understood to result from the action of strong electron-electron interactions. Nevertheless, the parallel role of the electron-phonon interaction in defining the cuprate phase-diagram is highlighted by the ubiquitous presence of charge-density-wave correlations in these materials. Although non-equilibrium studies have reported the observation of a transient superconducting state generated in response to the resonant pumping of select phonon modes [1], relatively little is understood about the dynamic properties of the electron-phonon interaction itself. Using time-resolved resonant x-ray scattering from La$_{1.65}$Eu$_{0.2}$Sr$_{0.15}$CuO$_4$ we studied the dynamic evolution of charge-density-wave order in response to ultrafast optical excitation, as a function of temperature and excitation fluence [2]. In a recent follow-up investigation, we tracked the corresponding structural dynamics across a wide doping range in both La$_{1.6-x}$Nd$_{0.4}$Sr$_x$CuO$_4$ and La$_{1.8-x}$Eu$_{0.2}$Sr$_x$CuO$_4$, which demonstrates that the transfer of energy from the transiently excited electronic system to the lattice becomes more rapid by at least one order of magnitude when entering the charge-density-wave phase. Most intriguingly, we demonstrate that the electron-phonon interaction strength can be renormalized by manipulating electronic degrees of freedom alone, thereby allowing ultrafast control of the electron-phonon coupling in these cuprates.

References:
1. D. Fausti et al. Science 331, 189–191 (2011).
2. M. Bluschke, N. Gupta et al. PNAS 121, e2400727121 (2024).

Speaker: Dr Martin Bluschke (Quantum Matter Institute - University of British Columbia, Vancouver, Canada)

14:35 Twists and Turns: Exploiting Azimuthal Dependences in the Ultrafast Time Domain

Ultrafast spin manipulation carries great potential for future information technology. Ferromagnets, which are commonly studied in this context, are limited by the dissipation of angular momentum. This is not the case for antiferromagnets, which offer both the prospect of faster and more efficient spin dynamics, as well as the possibility to exploit magnetic properties that are unavailable in ferromagnets. One such property is the internal arrangement of the spins. Controlling this arrangement can alter how the antiferromagnet stores data, interacts with neighboring materials, and more.
Resonant X-ray diffraction is commonly used to study spin arrangements in antiferro-magnets, and the azimuthal dependence of diffracted intensity can be collected. This information is particularly important when the Ewald sphere is limited by the use of soft X-ray resonance, so only a few reflections can be recorded.
Here I will discuss femtosecond soft X-ray resonant diffraction studies of antiferromagnetic spin dynamics. In these projects we take advantage of azimuthal angle dependences to disentangle the rearrangement of spin order from the “usual” demagnetization. We demonstrate deterministic ultrafast control of the spin arrangement, and we use the dynamic azimuthal data to retrieve intrinsic material properties associated with the spin dynamics.
The materials of focus are Lanthanide-based intermetallics [1-3].

REFERENCES
1. Y. W. Windsor et al., Communications Physics 3, 139 (2020)
2. Y. W. Windsor et al., Nature Materials 21, 514–517 (2022)
3. S.-E. Lee, et al., Phys. Rev. Research 6, 043019 (2024)

Speaker: William Windsor (TU Berlin & Fritz Haber Institute)

15:00 Ultrafast dynamics of magnetic anisotropy and magnetic structure in ferrimagnetic CoTb thin films

Speaker: Moundji Hemili (Sorbonne Université, CNRS, Laboratoire Chimie Physique - Matière et Rayonnement, LCPMR, 75005, Paris, France)

15:25 Magnetic Field Dependent Ultrafast Control of an Antiferromagnet

Antiferromagnetic (AF) spintronics is a promising route towards more efficient and stable devices, because antiferromagnets are less susceptible to external fields and foster a broad range of magnetic interactions with the potential for higher speeds and energy efficient manipulation. However, their self-cancelling magnetic moment makes the interaction with magnetic order challenging. One way to achieve this is to utilize the magnetic anisotropy (MA) to manipulate the spin arrangement which was demonstrated recently using ultrafast optical excitation [1]. External magnetic fields, as regularly used in ferromagnetic materials, can also have a strong influence on MA, providing an additional control knob on the AF magnetic order. Therefore, understanding the interaction of laser excitation induced transient MA with magnetic fields is of strong interest. To this end, we perform femtosecond time-resolved resonant soft X-ray diffraction (RSXRD) in the prototypical A-type antiferromagnet GdRh2Si2. Consistent with our previous study, we observe an ultrafast rotation of the AF arrangement of Gd 4f spins followed by coherent oscillations of the AF order as a consequence of a light-induced change in the MA potential.
Remarkably, while the AF order undergoes a spin-flop transition upon increasing magnetic field, the oscillations persist and their frequency increases while the amplitude of reorientation upon photoexcitation reverses its direction. To understand our observations, a phenomenological model is built based on the MA potential and Zeeman energy as two competing mechanisms, which reproduces the key features of the observed ultrafast dynamics. Our results demonstrate magnetic field control of the MA potential and may offer a new way towards deterministic control of spin order using combined electromagnetic and magnetic fields.
[1] Windsor et al. Commun Phys 3, 139 (2020)

Speaker: Abeer Arora (Fritz Haber Institut Berlin, Germany)

15:50 Break

16:05 Variable out-of-plane magnetic field for soft x-ray resonant magnetic reflectivity

Speaker: Dr Jean-Marc Tonnerre (CNRS, Institut Néel)

16:30 Helimagnetic Order in MnGe Thin Films Probed by RXMR

Speaker: Theodore Monchesky (Dalhousie University)

16:55 Current-driven Magnetisation Reversal in CoFeTaB/Pt Probed By X-ray Magnetic Reflectivity

ABSTRACT
Electrical control of magnetisation offers a promising alternative to conventional external magnetic fields for manipulating magnetic materials. This work investigates the current driven magnetisation reversal in CoFeTaB/Pt taking advantage of the magnetisation direction and the polarisation dependence of the X-ray scattering cross-section [1]. A current is applied perpendicular to the scattering plane to induce magnetisation reorientation within the plane [2]. Hysteresis curves are measured during the current cycle using both positive circular (pc) and negative circular (nc) polarisation at Fe-L3 resonance. The asymmetry ratios ((Rpc-Rnc)/(Rpc+Rnc)) derived from the X-ray magnetic reflectivity (XRMR) measured during the current cycle indicate transitions between two magnetic states. The XRMR measurements are performed in these magnetic states with circular polarisation as a function of angle. The asymmetry ratios in this case show slight variations in both magnetic states. The measurements with linear polarisation (sensitive to the out of scattering plane components of magnetisation) show significant asymmetries, suggesting a substantial perpendicular magnetisation component in the current-driven states and hence, incomplete magnetisation switching with applied current [3]. The optical modelling suggests that the magnetisation switching occurs primarily in the region close to the interface. Therefore, the interfacial magnetisation is probed by proximity-induced magnetism in the Pt layer. The XRMR measurements at Pt L3 edge during a current cycle reveal a hysteresis curve with sharp transitions between two magnetic states. The measurements on field driven hysteresis curves show that the Pt moments are aligned transverse to the bulk CoFeTaB magnetisation. The application of electric current results in the reorientation of this transverse magnetisation only, resulting in the incomplete magnetisation switching of the film.
REFERENCES
1. R. Fan, Kiranjot, R.O.M. Aboljadayel, K. Alsaeed, P. Bencok, D.M. Burn, A.T. Hindmarch, P. Steadman., J. Synchrotron Radiat. 31, 493 (2024).
2. D. M. Burn, R. Fan, O. Inyang, M. Tokac, L. Bouchenoire, A.T. Hindmarch, P. Steadman, Phys Rev B 106, 094429 (2022).
3. Kiranjot, R. Fan, R.O.M. Aboljadayel, D.M. Burn, K. Alsaeed, A.T. Hindmarch, P. Steadman, Jpn. J. Appl. Phys. 63, 098004 (2024).

Speaker: Kiranjot Dhaliwal (Diamond Light Source)

17:20 Spiral Spin Structure in Dy-Doped Spinel-Ferrite

Speaker: Dr Anupam Kumar Singh (Johannes Kepler University Linz)

17:45 → 18:00 Break

18:00 → 19:15 Poster session Wed

19:15 → 19:20 End of daily program & Announcements

Thursday, 9 October

09:00 → 12:55 Talks Thursday Morning

09:00 Capturing fluctuations in correlated oxides using x-ray photon correlation spectroscopy

Speaker: Dr Roopali Kukreja

09:35 Fluctuation and phase transition in amorphous FeGe thin film

Speaker: Dr Sujoy Roy (Lawrence Berkeley National Lab)

10:00 Microscopic Interactions in Skyrmion Hosts Via Spatiotemporal Lattice Dynamics

Speaker: Dr Andi Barbour

10:25 Soft X-ray Correlation Spectroscopy at Fourth Generation Synchrotron Source to Investigate Domain Fluctuations in Ho

Non-colinear spin structures have gained interest due to their connection to multiferroicity. One of most well-known examples of such materials is the helical antiferromagnetic Holmium. The occurrence of domain-wall fluctuations over a wide range of time scales has been observed [1]. These fluctuations show a slow dynamic on the order of nanoseconds to seconds and are important to understand thermally-activated magnetization reversal processes. In order to probe these dynamics, techniques with nanometer spatial resolution and nanosecond temporal resolution are necessary and thus making X-ray photon correlation spectroscopy (XPCS) the ideal method. However, the temporal resolution in the soft X-ray range is often-case still limited, among others due to the detector as well the lack of coherent soft X-ray scattering beamlines in fourth-generation sources. Until now, the dynamics of Ho on the micro- to nanosecond scale has therefore not been investigated yet.

In order to increase the temporal resolution in XPCS, we have recently commissioned a mobile resonant scattering endstation at the new coherent scattering beamline SoftiMAX at the fourth-generation synchrotron source MAX IV, Sweden. Even with a slow readout CCD, this setup combined with the high coherent flux provided new intriguing insights into the dynamics of domain fluctuations: Over only a small temperature range of 10 K the dynamics change by more than two orders of magnitude. In the long-term, the goal of this instrument is to push the resolution down to the nanosecond scale and enable single-shot XPCS in the soft X-range at synchrotrons.

[1] Konings et al., Physical Review Letters 106, 7 077402 (2011).

Speaker: Simon Marotzke (Deutsches Elektronen-Synchrotron DESY / Christian-Albrechts-Universität zu Kiel)

10:50 Coffee Break

11:15 Tittle to be defined (invited talk)

Speaker: Dr Miriam Garcia Fernandez

11:35 Resonant Scattering Investigations of Density Wave Ordering in the Bilayer Nickelate La3Ni2O7

The discovery of high-temperature superconductivity in La3Ni2O7 under has motivated the investigation of parent or competing phases which could shed light on the underlying pairing interaction and phase diagram. Here, we employ resonant elastic and inelastic soft x-ray scattering and polarimetry on thin films of bilayer La3Ni2O7 to reveal the existing of a spin density wave (SDW) which forms unidirectional diagonal spin stripes with moments lying within the NiO2 plane and perpendicular to the SDW wavevector. These stripes form anisotropic domains with shorter correlation lengths perpendicular versus parallel to the SDW wavevector, revealing nanoscale rotational and translational symmetry breaking analogous to the cuprate and Fe-based superconductors [1]. In addition, we also investigate another polymorph of La3Ni2O7, a repeating monolayer-trilayer structure (so-called “1313”) and compare the magnetic excitations and ordering between the two polymorphs.

Speaker: Kyle Shen (Cornell University)

12:00 Helicities of magnetic skyrmion lattices studied by circularly polarized resonant x-ray scattering (invited)

Speaker: Dr Takeshi Matsumura

12:25 Anisotropic Mesoscale Spin Structures In Non-Centrosymmetric Magnets Unveiled By Resonant Small-Angle X-ray Scattering

Speaker: Victor Ukleev (Helmholtz-Zentrum Belrin)

13:00 → 15:00 Lunch

15:00 → 22:00 Social program, Conference dinner

Friday, 10 October

09:00 → 12:00 Talks Friday Morning

09:00 X-Ray Beams with Orbital Angular Momentum: Resonant Scattering and Coherent Imaging

Speaker: Dr Maurizio Sacchi (Institut des NanoSciences de Paris (INSP, CNRS - Sorbonne Université) and Synchrotron SOLEIL)

09:25 Polarisation Analysis In Coherent X-ray Scattering Measurements

Speaker: Guillaume Beutier (Univ Grenoble Alpes - SIMaP)

09:50 Soft X-ray Transmission Holography at ESRF

Speaker: Flora YAKHOU-HARRIS (ESRF)

10:15 Coffee Break

10:35 Magnetic nano-domain microscopy and topology-sensitive modelling in Fe$_3$GeTe$_2$

ABSTRACT

Fe$_3$GeTe$_2$ (FGT) is a layered ferromagnetic solid with a Curie temperature of TC ≈ 205K. It is a layered material with out-of-plane magnetic anisotropy. We have performed microscopy investigations of the magnetic nano-domain structures in thin flakes of FGT. The data are acquired using the Fourier Transform Holography (FTH) technique with circular dichroism contrast at the iron L3 edge [1]. These studies complement measurements by scanning x-ray techniques [2], but the extension over a large range of temperatures and applied magnetic fields (B) allows for the creation of specific initial states by cooling from the paramagnetic phase through TC. We observe labyrinthine domains as well as small objects that are identified as Skyrmions. At low temperature, various structures emerge with increasing B field, and the patterns are readily erased by fields exceeding the coercivity. At high temperature, the Skyrmions are denser and re-emerge after reducing the B field.
The experimental study is complemented by modelling calculations based on band structure models with spin-orbit interactions explicitly considered [3]. The corresponding patterns match, and the trends on Skyrmion density in changing B fields are found to be qualitatively different for temperature well below TC and close to TC. This study allows us to conclude on the controllable transformation between these topological states in relation to the temperature dependence of the electronic band structure in FGT.

REFERENCES

1. Eisebitt, S. et al. Lensless imaging of magnetic nanostructures by X-ray spectro-holography. Nature 432, 885–888 (2004).
2. Powalla, L. et al. Seeding and emergence of composite Skyrmions in a van der Waals magnet. Adv. Mater. 35, 2208930 (2023).
3. Kathyat, D. S., Mukherjee, A., & Kumar, S. Microscopic magnetic Hamiltonian for exotic spin textures in metals. Phys. Rev. B 102, 075106 (2020).

Speaker: Moritz Hoesch (Deutsches Elektronen-Synchrotron DESY)

11:00 X-ray/XUV Coherence Isolated Diffraction Imaging

Coherent X-ray imaging is widely used to image nanoscale structures with high spatial resolution [1], and more recently to spatiotemporal dynamics [2]. However additional stochastic dynamics or birefringence of the sample lead to secondary scattering terms in diffractive signals. At high intensities in pump-probe experiments it is even possible to generate additional non-linear frequency shifted signals. Due to mutual incoherence of the probe signal and these additional components, these kinds of signals do not appear in the reconstructions of Fourier Transform Holography (FTH) and Coherent Diffraction Imaging (CDI) but can be of great significance to understanding the material properties. Recent efforts have shown the possibility of tracking fluctuations [3] to improve reconstruction or isolate the additional components through multi-wavelength CDI [4–6].

Here we present a framework called Coherence Isolated Diffraction Imaging (CIDI) to address these issues [7]. Leveraging the property of mutual incoherence, CIDI is capable of isolating additional signals from the diffracted probe and reconstructing both components separately from a single dataset. We demonstrate the working principle of CIDI and show the applicability of the method to isolate stochastic dynamics in nanoscale quantum materials, birefringent systems and ultrafast nonlinear processes in the X-ray domain.

[1] A. Sakdinawat and D. Attwood, Nanoscale X-ray imaging, Nat. Photonics 4, 840 (2010).
[2] A. S. Johnson et al., Ultrafast X-ray imaging of the light-induced phase transition in VO2, Nat. Phys. 19, 215 (2023).
[3] C. Klose et al., Coherent correlation imaging for resolving fluctuating states of matter, Nature 614, 256 (2023).
[4] M. Di Pietro Martínez, A. Wartelle, N. Mille, S. Stanescu, R. Belkhou, F. Fettar, V. Favre-Nicolin, and G. Beutier, Magnetic X-Ray Imaging Using a Single Polarization and Multimodal Ptychography, Phys. Rev. Lett. 134, 016704 (2025).
[5] E. Malm, E. Fohtung, and A. Mikkelsen, Multi-wavelength phase retrieval for coherent diffractive imaging, Opt. Lett. 46, 13 (2021).
[6] H. Lin, J. Niu, K. Li, P. Sheng, A. Lin, J. You, J. Li, X. Zhang, and F. Zhang, Single-frame multiwavelength coherent diffraction imaging using extreme ultraviolet high-harmonic comb sources, Chin. Opt. Lett. 23, 4 (2025).
[7] A. Sarkar and A. S. Johnson, Coherent X-ray imaging of stochastic dynamics, Mater. Adv. 5, 6378 (2024).

Speaker: Arnab Sarkar (IMDEA Nanociencia)

11:25 Lensless coherent imaging of nanoscale magnetic domains in 2D van-der-Waals materials

see attachment

Speaker: Daniel Pérez Salinas

12:00 → 13:30 Lunch

13:30 → 15:30 Bus to Barcelona downtown (airport shuttle/metro)