Marine cyanobacteria are main contributors to carbon and nitrogen fixation, yet they are limited by iron availability. The most abundant and smallest photosynthetic organism on Earth is the cyanobacterium Prochlorococcus that can thrive in low nutrient waters. Interestingly, in contrast to most cyanobacteria that possess two FutA proteins to bind Fe(II) and Fe(III), Prochlorococcus has a...
To measure the gravitation pull on Antimatter, the AEgIS collaboration at CERN aims to perform moiré deflectometry on a beam of cold Antihydrogen. For such a measurement to be sufficiently accurate, the resulting fringe pattern needs to be resolved with micrometric accuracy. Here we present the technology and design considerations behind the OPHANIM detector, a purpose built Antihydrogen...
This contribution discusses the application of Diffraction Computed Tomography (DCT), including both X-ray and neutron probes, as a powerful method for non-destructive structural analysis in materials science. DCT uses a pencil-beam scanning technique to yield the reconstructed images of internal structure and chemical gradients of materials, extending the traditional imaging approaches. A...
Hydrogen atoms represent a large fraction of the total atomic content of macromolecules. Macromolecular X-ray crystallography affords the localisation of only the most ordered hydrogen atoms at (sub-)atomic resolution (around 1.2 Å or higher). However, many hydrogen atoms of biochemical significance remain undetectable by this method. Differently, neutron diffraction methods enable the...
LiCoO2 (LCO) has been proven for extensive commercial applications owing to its high specific capacity and stability. Therefore, there has been considerable interest in further enhancing its specific capacity by increasing the charging voltage. However, single-crystal LCO suffers from a significant capacity degradation when charged to 4.5 V due to the irreversible phase transition and unstable...
We have studied the heme-protein-lipid interaction with lipid bilayers. This is key for understanding the encapsulation of the iron binding heme-protein like myoglobin and phytoglobin, in lipid nanoparticles, LNPs. This type of heme-bound iron can be used to treat anaemia instead of iron in organic salts that is conventionally used. Encapsulation is needed to prevent unwanted proteolytic and...
This comprehensive study delves into the complex magnetic properties and interactions of the perovskite-like compound CaCu$_3$Ti$_4$O$_{12}$, employing advanced neutron scattering techniques and resonant inelastic X-ray scattering (RIXS) to explore the underlying spin-orbital coupling and single-ion anisotropy. By synthesizing high-quality single crystals and utilizing a four-circle neutron...
Depth resolved positron annihilation Doppler-broadening spectroscopy (DBS) at
the top-most atomic layer of solid materials is a fundamental but largely
unexplored field of research. This is because it requires monoenergetic
positron beams with energies in the order of only a few of eV.
SLOPE (Setup for LOw-energy Positron Experiments) is specially designed for
a low energy beam, enabling...
LumaCam detectors have a structure resembling many established scintillator-based imaging detectors. The key difference is the imaging chip being fast enough to identify the individual scintillaton photons produced by a neutron interaction in the scintillator screen. This information can be used to provide enhanced spatial and temporal resolution, as well as noise suppression and particle...
Nickel-aluminum bronze (CuBz) alloys are widely used due to their excellent mechanical properties and corrosion resistance. To enhance their use in high-value applications and lower the part replacement costs, improving their surface wear resistance is essential. Metal matrix composite (MMC) coatings have shown promise in this regard. One approach involves laser melting injection (LMI) of...
Pyrochlore magnets (R₂M₂O₇), with rare-earth ions arranged on corner-linked tetrahedra, are key to understanding magnetic frustration. These systems display diverse magnetic behaviors, including spin ice and spin liquid. Recently, researchers are exploring exotic magnetism by chemically manipulating or diluting these spin systems. We present magnetization and neutron-scattering measurements on...
To increase neutron flux on small samples, we are developing a nested mirror optic (NMO) array for the PUMA thermal triple-axis spectrometer. This device is intended to reduce the beam size to 5 mm x 5 mm while preserving 50% of the incoming neutrons, resulting in an 8-fold increase in the flux available for small samples. However, the complex neutron flight paths generated from novel optics...
Within the DAPHNE4NFDI consortium MLZ has been working on providing a FAIR data access option. The central part will be the MLZ datacatalogue ( which should be available before the Usermeeting).
We will show how the data in the catalogue look like, how you can really access it and a give an outlook on the coming data access options.
Polarized neutron diffraction is proven to be a powerful tool for studies of magnetic structure and microscopic dynamics of matter. This is assured by the success of the XYZ-polarization analysis technique, which lays the basis for separation of coherent, incoherent, and magnetic contributions to the scattering cross section. Even though polarized diffraction can provide a more robust...
Ba3MA2O9 compounds have gained significant attention due to various exotic magnetic ground states depending upon the various combinations of M and A atoms. For instance: Ba3NiSb2O9, Ba3CuSb2O9, and Ba3IrTi2O9 exhibit quantum spin-liquid behavior [1-3], while Ba3ZnIr2O9 [4] shows a quantum spin-orbital liquid state. However, the magnetic ground of these compounds with M = rare-earth and A = 4d...
Recent developments of scintillator-based event-driven detectors have opened up the possibility of utilizing AI to identify single neutron events from sparse data readout. A crucial aspect for AI-based event detection is to provide training datasets that can be utilized to accurately train a neural network. Such training datasets require a “ground-truth” to avoid errors in the event...
Small-angle neutron scattering is useful for probing nanometer-scale structures but inhomogeneous materials like ball-milled powders used for hydrogen storage often yield fairly featureless diffraction patterns that are difficult to interpret [1]. Despite this, such patterns can still reveal important information. To explore this, Aslan et al. conducted an in situ investigation, measuring...
I will review the main works done in the last years by my research group in collaboration with the researchers of NEPOMUC. These works include studies on vacancy like defects in silicon based materials, oxides, materials for hydrogen storage and soft matter.
At the light of the obtained results I will discuss the experimental requirements for a new class of measurements in material science at NEPOMUC.
The symmetry of the material is an important factor determining its properties. In this work, we demonstrate [1] both experimentally and by numerical simulations that the actual symmetry of the rutile phase of TiO2 is CaCl2-type [2] orthorhombic, described with space group Pnnm, in contrast to what it is commonly believed that rutile TiO2 has a tetragonal symmetry [2-4], described with space...
Neutron imaging with cold and thermal neutrons typically use scintillator screens that use lithium-6 as a neutron converter. Compared to lithium-6, boron-10 offers nearly four time higher neutron absorption cross-section and larger daughter products that deposit their energy locally, offering the potential for higher neutron capture efficiency and spatial resolution. Screens were fabricated...
Organic-inorganic halide perovskites have gained a huge interest in the scientific community owing to their favorable optoelectronic properties combined with their ease of production and abundance of raw materials. In many cases, polycrystalline thin films are fabricated for which thin film crystallinity and morphology are key factors affecting the perovskite properties. In this work, we...
LaCoO$_3$ has been the subject of an intense investigation due to its intriguing transformation from a nonmagnetic insulator at low temperatures to a paramagnetic semiconductor, followed by an insulator-to-metal crossover. The nature of these transitions is the topic of long-standing and ongoing discussions. Generally, these crossovers are associated with the population of Cobalt low-spin (S =...
Pulsed low-energy positron beams of variable energy are powerful
tools for defect profiling in materials with positron annihilation lifetime spectroscopy (PALS). The UniBwM operates two pulsed positron beams at NEPOMUC: The Pulsed Low-Energy Positron System (PLEPS) for depth-resolved (1D-)defect profiling and the Scanning Positron Microscope (SPM), which in addition offers lateral micrometer...
Pt/Co/Pt and Pd/Co/Pd heterostructures with perpendicular magnetic anisotropy (PMA) are traditionally used for magnetic recording. PMA can be tuned by e.g. thin film thickness, strain, ion bombardment or temperature. Recently, it has been shown that the absorption of hydrogen in the heavy metal modifies the interfacial spin-orbit coupling and hence reduces the PMA.[1-3] As a result, reversible...
Microplastics have become a pressing issue due to their accumulation in aquatic and terrestrial environments and their presence in the food chain. In this talk, I will present the studies undertaken to flocculate a model microplastic system, viz., polystyrene latex suspension. This system, comprised of ~140 nm polystyrene spheres (microplastic) dispersed in water, was flocculated using...
Microgels - crosslinked polymer networks swollen in a good solvent - have been used to investigate the effect of compressibility on crystal and glass formation, and on its relation with the flow proprieties of the suspensions [1]. Their compressibility strongly affects microgels at interfaces [1, 2]. Here, poly(N-isopropylacryamide) (pNIPAM)-based microgels are confined at the oil- and...
The aim of our research is to achieve a fundamental understanding of compressible soft materials, both static and under flow, and use this knowledge to further develop bio-relevant colloids. An object's bulk modulus K quantifies its resistance to an isotropic compression. For deformable colloids, K must be known to predict their response to crowding. Here, we will first present a new approach...
At the FRM II a UCN source with a solid deuterium converter and solid hydrogen premoderator, placed in a distance of ∼ 60 cm from the central fuel element inside the horizontal, through-going beam tube SR6, is currently under construction. It is supposed to generate UCN densities of 1000 - 10000 UCN per cubic centimeter in up to four connected experiments. This talk will give an overview of...
We investigated a quasi-binary liquid of 3-methyl pyridine and heavy water at the critical composition at different temperatures close to the phase transition. When adding antagonistic salt sodium tetraphenylborate the ions form locally lamellar structures that enclose the binary fluid. Then the system becomes 2-dimensional. Looking at the critical fluctuations, the dimensionality is...
The Proton Electron Radiation Channel (PERC) experiment will investigate the decay of the neutron by observing spectra of the emerging electrons and protons, and several correlations between neutron spin, and the electron, proton, and neutrino momenta. Its aim is in particular to improve on the parity violating beta asymmetry, and the Fierz term by an order of magnitude. PERC is under...
Magnonics is a multidisciplinary field of research focusing on the study and application of magnons in information processing and technology [1]. Magnons can carry the spin information through thermally generated spin-wave spin currents over the large distances [2]. Insulating antiferromagnets (AFMs) are promising for next-generation high-density and high-speed spintronic applications due to...
The metal halide perovskites (MHPs) are attracting intense research interest due to their excellent optoelectronic properties. The all-inorganic member CsPbBr$_3$ is of particular interest for gamma-ray detector applications and LEDs. Further, single crystals can be grown via a solution route or by a melt process, and thin films can be solution processed or produced by vapour deposition....
PEDOT:PSS is a water-dispersable and electrically conductive polymer blend that is increasingly applied in numerous fields such as batteries and super-capacitors. While many studies focus on performance optimization, degradation issues because of humid environments are rarely discussed: PEDOT:PSS absorbs significant amounts of water (~50 wt%), which leads to a pronounced swelling factor of up...
