New at Campus Wannsee: CoreLab Quantum Materials
This optical zone melting furnace is producing large single crystals. © M. Setzpfandt/HZB
A Laue apparatus is used for precise alignment of the crystals. © M. Setzpfandt/HZB
Phase transitions can be detetcted by measuring transport properties of the sample. © M. Setzpfandt/HZB
Helmholtz-Zentrum Berlin has expanded its series of CoreLabs for energy materials research. In addition to the five established CoreLabs, it has now set up a CoreLab for Quantum Materials. A research team from the HZB Institute for Quantum Phenomena in New Materials is responsible for the CoreLab and its modern equipment. The CoreLab is also open to experimenters from other research institutes.
Quantum phenomena are typically easiest to observe within perfect single crystals at very low temperatures. A team led by Prof. Dr. Bella Lake and Dr. Konrad Siemensmeyer has set up a dedicated CoreLab for Quantum Materials for producing and experimenting with such single crystals in the laboratory, or for preparing them for measurements at the neutron source BER II or the synchrotron light source BESSY II. External researchers are also welcome to use this CoreLab and benefit from the expertise of the HZB team.
Growth and preparation of single crystals
In many cases, the materials of interest are initially produced as microcrystalline powders and not as single crystals. Even the process of synthesising these powders is often difficult. It is therefore a key topic at this HZB CoreLab. In a powerful optical zone melting furnace, powder samples can be regrown as larger single crystals, which yield far more meaningful experimental results. Growing single crystals from powder samples requires a great deal of experience, which HZB possesses. A Laue apparatus is used for precise alignment of the crystals. Next, the crystals are cut in orientation with a wire saw or their surfaces polished in preparation for further experiments. The methods are highly flexible and suitable for all possible experiments. Samples are easily prepared here for experiments at the neutron source, at BESSY II, or in the lab. Less experienced users are closely supervised to ensure the success of their experiments.
Transport properties and phase transitions
Another room provides high magnetic fields, low temperatures with two “Physical Property Measurement Systems” and a sensitive SQUID magnetometer. These allow the measurement of transport properties such as thermal conductivity, magnetisation and specific heats of materials. Measuring these properties renders so-called phase transitions visible. These phase transitions have a correlation with quantum physical laws and indicate the formation of new structures within the material.
CoreLabs for users in academia and industry
As an operator of large facilities, HZB has great experience in organising external user operation. HZB is now also introducing this experience into the operation of its CoreLabs, which are equipped with latest generation, and sometimes unique, instruments and equipment for analysing and synthesising energy materials. International experimental guests and partners from industry are equally welcome here.
- Battery research with the HZB X-ray microscopeNew cathode materials are being developed to further increase the capacity of lithium batteries. Multilayer lithium-rich transition metal oxides (LRTMOs) offer particularly high energy density. However, their capacity decreases with each charging cycle due to structural and chemical changes. Using X-ray methods at BESSY II, teams from several Chinese research institutions have now investigated these changes for the first time with highest precision: at the unique X-ray microscope, they were able to observe morphological and structural developments on the nanometre scale and also clarify chemical changes.
- BESSY II: New procedure for better thermoplasticsBio-based thermoplastics are produced from renewable organic materials and can be recycled after use. Their resilience can be improved by blending bio-based thermoplastics with other thermoplastics. However, the interface between the materials in these blends sometimes requires enhancement to achieve optimal properties. A team from the Eindhoven University of Technology in the Netherlands has now investigated at BESSY II how a new process enables thermoplastic blends with a high interfacial strength to be made from two base materials: Images taken at the new nano station of the IRIS beamline showed that nanocrystalline layers form during the process, which increase material performance.
- Hydrogen: Breakthrough in alkaline membrane electrolysersA team from the Technical University of Berlin, HZB, IMTEK (University of Freiburg) and Siemens Energy has developed a highly efficient alkaline membrane electrolyser that approaches the performance of established PEM electrolysers. What makes this achievement remarkable is the use of inexpensive nickel compounds for the anode catalyst, replacing costly and rare iridium. At BESSY II, the team was able to elucidate the catalytic processes in detail using operando measurements, and a theory team (USA, Singapore) provided a consistent molecular description. In Freiburg, prototype cells were built using a new coating process and tested in operation. The results have been published in the prestigious journal Nature Catalysis.