HZB Newsroom

Freeze casting is an elegant, cost-effective manufacturing technique to produce highly porous materials with custom-designed hierarchical architectures, well-defined pore orientation, and multifunctional surface structures. Freeze-cast materials are suitable for many applications, from biomedicine to environmental engineering and energy technologies. An article in "Nature Reviews Methods Primer" now provides a guide to freeze-casting methods that includes an overview on current and future applications and highlights characterization techniques with a focus on X-ray tomoscopy.

Burning biomass for cooking causes harmful environmental and health issues. The German-South African GreenQUEST initiative is developing a clean household fuel. It aims to reduce climate-damaging CO₂ emissions and to improve access to energy for households in sub-Saharan Africa.

A team at HZB has investigated a new, simple method at BESSY II that can be used to create stable radial magnetic vortices in magnetic thin films.

An improved charging protocol might help lithium-ion batteries to last much longer. Charging with a high-frequency pulsed current reduces ageing effects, an international team demonstrated. The study was led by Philipp Adelhelm (HZB and Humboldt University) in collaboration with teams from the Technical University of Berlin and Aalborg University in Denmark. Experiments at the X-ray source BESSY II were particularly revealing.

New states of order can arise in quantum magnetic materials under magnetic fields. An international team has now gained new insights into these special states of matter through experiments at the Berlin neutron source BER II and its High-Field Magnet. BER II served science until the end of 2019 and has since been shut down. Results from data at BER II are still being published.

The travelling salesman problem is considered a prime example of a combinatorial optimisation problem. Now a Berlin team led by theoretical physicist Prof. Dr. Jens Eisert of Freie Universität Berlin and HZB has shown that a certain class of such problems can actually be solved better and much faster with quantum computers than with conventional methods.

Hafnium oxide thin films are a fascinating class of materials with robust ferroelectric properties in the nanometre range. While their ferroelectric behaviour is extensively studied, results on piezoelectric effects have so far remained mysterious. A new study now shows that the piezoelectricity in ferroelectric Hf_0.5Zr_0.5O₂ thin films can be dynamically changed by electric field cycling. Another ground-breaking result is a possible occurrence of an intrinsic non-piezoelectric ferroelectric compound. These unconventional features in hafnia offer new options for use in microelectronics and information technology.

Sodium-ion batteries still have a number of weaknesses that could be remedied by optimising the battery materials. One possibility is to dope the cathode material with foreign elements. A team from HZB and Humboldt-Universität zu Berlin has now investigated the effects of doping with Scandium and Magnesium. The scientists collected data at the X-ray sources BESSY II, PETRA III, and SOLARIS to get a complete picture and uncovered two competing mechanisms that determine the stability of the cathodes.

High-entropy alloys can withstand extreme heat and stress, making them suitable for a variety of specific applications. A new study at the X-ray synchrotron radiation source BESSY II has now provided deeper insights into the ordering processes and diffusion phenomena in these materials. The study involved teams from HZB, the Federal Institute for Materials Research and Testing, the University of Latvia and the University of Münster.

Yan Lu is appointed new Professor of Hybrid Materials for Electrochemical Energy Storage and Conversion at Friedrich Schiller University Jena together with HZB. Congratulations!

Processing materials on the nanoscale, producing prototypes for microelectronics or analysing biological samples: The range of applications for finely focused ion beams is huge. Experts from the EU collaboration FIT4NANO have now reviewed the many options and developed a roadmap for the future. The article, published in “Applied Physics Review”, is aimed at students, users from industry and science as well as research policy makers.

The production of green hydrogen requires catalysts that control the process of splitting water into oxygen and hydrogen. However, the structure of the catalyst changes under electrical tension, which also influences the catalytic activity. A team from the universities of Duisburg-Essen and Twente has investigated at BESSY II and elsewhere how the transformation of surfaces in perovskite oxide catalysts controls the activity of the oxygen evolution reaction. 

Anodes for the electrolytic splitting of water are usually iridium-based materials. In order to increase the stability of the iridium catalyst, a team at HZB and a group at HI-ERN have now produced a so-called material library: a sample in which the concentration of iridium and titanium oxides is systematically varied. Analyses of the individual sample segments at BESSY II in the EMIL laboratory showed that the presence of titanium oxides can increase the stability of the iridium catalyst significantly.

The Highlights 2022 report on a selection of the most important research results and events at HZB.

Several HZB research teams are participating in the new SFB 1636 "Elementary processes of light-driven reactions on nanoscale metals".

Many enzymes promise to break down plastic. But what works well in the lab often fails on a large scale. Now a new study by Gert Weber, HZB, Uwe Bornscheuer, University of Greifswald, and Alain Marty, Chief Scientific Officer of Carbios, shows how raising the bar for laboratory experiments could help identify promising approaches more quickly. The team demonstrated the new standards on four newly discovered enzymes.

It really is a problem: Microplastics are everywhere. Now, an HZB and University Potsdam team developed a method that for the first time enables us to precisely localise microplastics in soil. The combined 3D tomographies by neutrons and X-rays show exactly the location of particles and structural changes that can affect water flows and soil properties.

The first high-level event of the Green Deal Ukraina (GDU) project took place in October in Kyiv, Ukraine, attended by more than 150 participants. This first gathering and formal launch took place at an important moment: EU will share a new report on the countries progress towards EU and Ukraine will respond by sharing its own analysis, called pre-screening.

It already works: there are several approaches to using solar energy to split water and produce hydrogen. Unfortunately, this green hydrogen has so far been more expensive than grey hydrogen from natural gas. A study by Helmholtz-Zentrum Berlin (HZB) and Technische Universität Berlin now shows how green hydrogen from sunlight can become profitable.

Freeze casting processes can be used to produce highly porous and hierarchically structured materials that have a large surface area. They are suitable for a wide variety of applications, as electrodes for batteries, catalyst materials or in biomedicine. A team led by Prof. Ulrike G. K. Wegst, Northeastern University, Boston, MA, USA and Dr. Francisco García Moreno from the Helmholtz-Zentrum Berlin have used the newly developed X-ray tomoscopy technique. At the Swiss Light Source of the Paul Scherrer Institute they observed in real time and at high resolution how the process of structure formation takes place during freezing. A sugar solution served as the model system.

With increasing size and complexity, quantum computers become a sort of black box. Using methods from mathematical physics, a team has now succeeded in deriving concrete numbers from random, data sequences that can serve as a benchmark for the performance of a quantum computer system. Experts from Helmholtz-Zentrum Berlin, Freie Universität Berlin, Qusoft Research Centre Amsterdam, the University of Copenhagen and the Technology Innovation Institute Abu Dhabi were involved in the work, which has now been published in Nature Communications.

X-ray microscopy (cryo-SXT) enables high-resolution insights into cells and cell organelles - in three dimensions. Until now, the 3D data sets have been analysed manually, which is very time-consuming. A team from Freie Universität Berlin has now developed a self-learning algorithm based on a convolutional neural network. In collaboration with experts in cell biology (FU Berlin) and X-ray microscopy at the Helmholtz Zentrum Berlin, this algorithm has now been used for the first time to analyse cell components in cryo-SXT data sets. It identified cell organelles and produced highly detailed, complex 3D images within a few minutes.

Friedrich Schiller University Jena and the Helmholtz-Zentrum Berlin (Helmholtz Centre for Materials and Energy, HZB) will jointly establish the "Helmholtz Institute for Polymers in Energy Applications" (HIPOLE) on 1 July 2023. The aim of HIPOLE is to develop sustainable polymer materials for energy technologies that can be rapidly brought into application, in particular polymer-based batteries and perovskite solar cells with polymer additives. HIPOLE will be funded with up to 5.5 million euros per year by the Federal Ministry of Education and Research (BMBF, 90%) and the Free State of Thuringia (10%). In the start-up phase until 2028, the Free State of Thuringia will additionally fund the new institute with more than ten million euros and take over the financing of the construction costs for the laboratories and offices.

A team of HZB has investigated the electronic structure of  Au₂Pb at BESSY II by angle-resolved photoemission spectroscopy across a wide temperature range: The results are in accordance with the electronic structure of a three-dimensional topological Dirac semimetal, in agreement with theoretical calculations.

Green Deal Ukraina, funded by the German Federal Ministry of Education and Research, is working with partner institutions in Ukraine and Poland to establish an energy and climate think tank in the capital, Kiev. The aim is to provide independent and evidence-based advice on rebuilding a sustainable energy system in Ukraine. After all, the implementation of energy and climate legislation is a prerequisite for Ukraine's accession to the EU. The project started on 1 June 2023 and will run for four years.

Magnetic domains walls are known to be a source of electrical resistance due to the difficulty for transport electron spins to follow their magnetic texture. This phenomenon holds potential for utilization in spintronic devices, where the electrical resistance can vary based on the presence or absence of a domain wall. A particularly intriguing class of materials are half metals such as La_2/3Sr_1/3MnO₃ (LSMO) which present full spin polarization, allowing their exploitation in spintronic devices. Still the resistance of a single domain wall in half metals remained unknown. Now a team from Spain, France and Germany has generated a single domain wall on a LSMO nanowire and measured resistance changes 20 times larger than for a normal ferromagnet such as Cobalt.

A new quasiparticle with interesting properties has appeared in solid-state physics - but so far only in the theoretical modelling of solids with certain magnetic properties. An international team from HZB and Freie Universität Berlin has now shown that, contrary to expectations, quantum fluctuations do not make the quasiparticle appear more clearly, but rather blur its signature.

Are you a 10th to 13th grade student interested in mathematics and science? Then secure your free VIP ticket for a tour with exciting experiments and insights during the Long Night of Science! Meet female scientists who are passionate about making our world a better place! 17.06. , from 5.30 pm, Adlershof Research Campus.

In April, Dr. Jie Wei started his research work in the Helmholtz Young Investigator Group Nanoscale Operando CO₂ Photo-Electrocatalysis at Helmholtz-Zentrum Berlin (HZB) and Fritz Haber Institute (FHI) of the Max Planck Society. Wei received one of the highly competitive Humboldt postdoctoral research fellowships and will pursue his two-year project under the guidance of the academic hosts Dr. Christopher Kley and Prof. Dr. Beatriz Roldan Cuenya.