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HZDR Research Talks

The HZDR Research Talks usually take place on Wednesdays from 1:00 to 2:00 p.m.

The next dates are:


May 19, 2021 "Radiographic methods for foam and froth flow"

by Dr. Sascha Heitkam (Transport processes at interfaces)

Foam and froth flow plays an important role in many processes such as froth flotation, foam fractionation or fire fighting. Nevertheless, liquid foam flow is not yet well understood. Foam flow is a complex process on several length scales, bridging surfactant sorption, liquid fraction redistribution, and bubble rearrangement. At the same time, many established measurement techniques are not applicable to opaque, fragile and complex foam. Radiographic methods pose a suitable approach to research aqueous foam. They yield unique insights into foam velocity, drainage, foam rheology and particle transport.

The talk will give an introduction to the unique mechanics of liquid foam and present recent results from X-ray particle tracking, X-ray tomography and neutron radiography. Finally, the application of alternative techniques such as MRI or PET will be discussed, which might allow for future collaborations inside HZDR.


May 12, 2021 "Slice them right - Experiments on FIB-patterned quantum materials under challenging conditions "

by Dr. Toni Helm (strongly correlated electron systems)

In order to uncover and understand the physics of topical quantum materials, experiments are pushed to their limits in terms of setup dimensions and resolution. One major challenge for investigations of new materials is the size and shape of real-life single crystals. Another hurdle to experiments is that most of the interesting physics occurs on length scales much smaller than the actual sample dimensions. In our approach, we apply focused ion beam (FIB) micromachining for the fabrication of micron-scale devices from bulk single crystals.
Our research focuses on the mesoscale regime, i.e., typical sizes of our structures are in the range of 10 nm - 100 μm. This range covers many of the relevant length scales in quantum materials, such as coherence lengths in superconductors, domain sizes in quantum magnets or the mean-free-paths in clean metals.
In this talk, I will exemplify some of our recent projects that benefited from FIB assisted patterning and uncovered new physics in topical materials. For example, we are able to explore highly conductive heavy-fermion metals under challenging conditions, such as pulsed magnetic fields and high pressures, with unprecedented quality [1,2]. Furthermore; I will show how we can contribute to the field of unconventional magnetism. As an example, I will present very recent results from electrical-transport experiments that we combined with microscopic magneto-sensitive imaging tools. This enabled us to reveal the topological transport signature of Antiskyrmions in the Heusler Mn1.4PtSn and Skyrmion bubbles in the hard magnet MnBi [3,4]

[1] F. Ronning, T. H. et al., Nature 548, 313–317 (2017)
Electronic in-plane symmetry breaking at field-tuned quantum criticality in CeRhIn5
[2] T. Helm, et al., Nat. Commun. 11, 3482 (2020)
Pressure-induced critical suppression of high-field nematicity in CeRhIn5
[3] M. Winter, T. H. et al., To be published (2021)
[4] Y. He, T.H. et al., unpublished, Preprint at arXiv:2011.06340 (2020)
Topological Hall effect arising from the mesoscopic and microscopic non-coplanar magnetic structure in MnBi


The HDZR Research Talks are a program for HZDR employees of all research fields. Within this framework, scientists give lectures on current projects, methods and procedures and look forward to exchanging ideas with colleagues in order to jointly develop ideas and initiate projects. The Research Talks are also open to external interested parties.

  • Lectures and discussions are held in English.
  • Participation is free of charge.
  • Registration is not required. External visitors need to check in at the HZDR main entrance 30 min in advance.

Initiator:
Dr. Franziska Lederer (Helmholtz Institute Freiberg for Resource Technology, Dept. Biotechnology)
Phone: +49 351 260 2427
E-Mail: f.lederer@hzdr.de

Co-organizers:
Dr. Kristof Zarschler (Institute of Radiopharmaceutical Cancer Research, Dept. Radionuclide Theragnostics)
Phone: +49 351 260 3678
E-Mail: k.zarschler@hzdr.de

Dr. Peter Zahn (Institute of Ion Beam Physics and Materials Research, Dept. Scaling Phenomena)
Phone: +49 351 260 3121
E-Mail: p.zahn@hzdr.de

Dr. Björn Drobot (Institute of Resource Ecology, Dept. Biogeochemistry)
Phone: +49 351 260 2759
E-Mail: b.drobot@hzdr.de

Dr. Sandra Hamann (Research Programmes and International Projects)
Phone: +49 351 260 3649
E-Mail: s.hamann@hzdr.de


Past lectures: