Welcome to LINXS Science Day, which this time will focus on the results and impact of the New Materials Theme, as well as give insight on future developments of LINXS, MAX IV and ESS. The afternoon will end with an interesting panel discussion chaired by the directors of ESS and MAX IV on future developments of the facilities and their strengths (and possible gaps) in the fields of energy and sustainability.

We hope to see many of you at LINXS!

When: April 22, 2024, 09:00–17:00 incl lunch and mingle

Where: at LINXS (5th floor, Sheelevägen 19, Lund), with digital possibility (Zoom)

Registration information: Please indicate in the registration if you would like to bring a poster to the poster session/mingle in the afternoon.

Online participants will receive a Zoom link a few days before the event.

Registration deadline: Please register before 17 April. After that we cannot guarantee lunch.

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agenda

09:15–09:30 Welcome and Introduction (New Material’s leader Elizabeth Blackburn and LINXS Director Trevor Forsyth)

09:30–10:15 Charge Transfer Materials (working group 2)

Speakers:

• Dr Verena Markmann (Technical University of Denmark, Denmark), “Light-induced Dynamics in and around Solvated Complexes”

• Dr Thai Pham (Lund University, Sweden), “Development of ultrafast x-ray absorption spectroscopic measurement at FemtoMAX beamline, MAX IV laboratory”

• Dr Alfred Larsson (Lund University, Sweden), “Oxidation and Reduction of a Gold Model Electrocatalyst”

10:15–11:00 Functional Magnetic Materials (working group 1)

Speakers:

• Prof Andreas Michels (University of Luxembourg), “Neutron scattering fingerprint of vortexlike flux closure in nanostructures”

• Dr Annika Stellhorn (European Spallation Source, Sweden), “Magnetic SANS – Prospects of data analysis”

• Dr Erik van Loon (Lund University, Sweden), “Electronic correlations in two-dimensional materials”

11:00–11:15 Coffee break

11:15–12:00 Nanostructures and Interfaces (working group 4)

• Dr Calle Preger (MAX IV Laboratory, Sweden), “In-flight XPS studies on aerosols and non-supported nanoparticles using the newly developed aerosol sample delivery system at MAX IV Laboratory”

• Mehran Sedrpooshan (Lund University, Sweden), “Multifunctional 1D magnetic self-assemblies”

12:00–12:45 Catalysis (working group 5)

Speakers:

• Dr Jan Knudsen (MAX IV/Lund University, Sweden), “Probing minority sites and their activity using chemical perturbations and Fourier Transformed Ambient Pressure X-ray Photoelectron Spectroscopy”

• Dr Sabrina Gericke (Lund University, Sweden), “Characterization of oxide-based catalysts and model catalysts for renewable fuels”

13:00–14:00 Lunch

14:00–16:00 Panel discussion Chairs: Helmut Schober (Director of European Spallation Source), Olof “Charlie” Karis (Director of MAX IV), Elizabeth Blackburn (New Materials theme leader)

Within the New Materials for Energy and Sustainability theme, there was a focus on specific scientific areas, namely magnetic materials, catalysts and charge transfer materials. To be successful, these studies impose certain particular requirements on the beamlines, instrumentation, and data handling required. Some of the theme’s activities have focussed on these aspects, as we will hear in the morning session. 

In the discussion round, we would like to focus on:

1. the facilities’ view of their strengths in these areas, and if there are any gaps

2. input from theme members on developments they would like to see

3. are there any particular sticking points

4. input from other LINXS themes if time permits

16:00–17:00 Poster session and mingle

• Speaker abstracts

  Neutron scattering fingerprint of vortexlike closure in nanostructures

  Andreas Michels, Department of Physics and Materials Science, University of Luxembourg

  Research into magnetic nanoparticles is being propelled by their promising applications across diverse fields such as medicine, biology, and nanotechnology. Numerous studies have highlighted their potential in targeted drug delivery, imaging, and hyperthermia treatment. However, assumptions about the uniformity of the magnetization distribution within nanoparticles, often made in application-oriented studies, can fall short in capturing the true complexity of these systems. This complexity is exemplified in magnetic hyperthermia, where microstructural defects may lead to enhanced specific absorption rates compared to defect-free particles. Understanding the spin structure of nanoparticles thus becomes pivotal not only for fundamental scientific inquiry but also for optimizing technological applications. To delve into the magnetic microstructure of nanoparticles and its relation to macroscopic properties both observational and computational methods are crucial. Among experimental techniques, magnetic small-angle neutron scattering (SANS) stands out as it can probe spin structures on the mesoscopic length scale and within the volume of magnetic materials. Consequently, numerous experimental SANS investigations, including those on ferrofluids, have been conducted to date, revealing a plethora of nonuniform spin configurations within nanoparticles. These configurations range from canted to vortex-type or core-shell-type arrangements, underscoring the rich complexity of magnetic behavior at the nanoscale. Complementing experimental efforts, numerical micromagnetic simulations are increasingly valuable in predicting nanoparticle spin structures and their related scattering signatures. These simulations consider various factors influencing the magnetic ground state of nanoparticles, such as particle size, shape, defects, and magnetic interactions. Here, by combining SANS with numerical micromagnetic computations, we discuss the transition from single-domain to multi-domain behavior in nanoparticles and its implications for the ensuing magnetic SANS cross section. Above the critical single-domain size we find that the cross section and the related correlation function cannot be described anymore with the uniform particle model, resulting, e.g., in deviations from the well-known Guinier law. In the simulations we identify a clear signature for the occurrence of a vortexlike dipolar-energy-driven spin structure at remanence  the magnetic correlation function exhibits a damped oscillatory behavior. Recent experimental SANS data on an isotropic Nd-Fe-B magnet seem to support the occurrence of mesoscaled flux-closure patterns in the magnetic microstructure that give rise to the corresponding feature in the correlation function. The resulting field dependence of the correlation length exhibits a power-law behavior that varies with a different exponent than the numerically-computed data, which poses a challenge to theory.

  Multifunctional 1D magnetic self-assemblies

  Mehran Sedrpooshan, Lund University, Sweden

  During this presentation, I will introduce our novel template-free methodology for the fabrication and direct integration of 1D magnetic self-assembled structures. Following the characterization results, I will showcase the functionality of the structures as magnetoresistive components and also magnetic actuators for potential applications in soft robotics.

Contact

For practical questions please contact josefin.martell@linxs.lu.se

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