Electrons confined in an aluminium film of a few atomic layers thick create mechanical stress equivalent to up to one thousand times the standard atmospheric pressures
Read heads in hard drives, lasers in DVD players, transistors on computer chips, and many other components all contain ultrathin films of metal or semiconductor materials. Stresses arise in thin films during their manufacture. These influence the optical and magnetic properties of the components, but also cause defects in crystal lattices, and in the end, lead to component failure. As researchers in the department of Eric Mittemeijer at the Max Planck Institute for Intelligent Systems in Stuttgart have now established, enormous stresses in the films are created by a quantum-mechanical mechanism that has been unknown until now, based on an effect by the name of quantum confinement. This effect can cause stresses equivalent to one thousand times standard atmospheric pressure, dependent of thickness. Knowledge of this could be helpful in controlling the optical and mechanical properties of thin-film systems and increase their mechanical stability. Additionally, very sensitive sensors might also be developed on the basis of this knowledge.
Unter den insgesamt 14 Preisträgern befinden sich vier Nachwuchswissenschaftler, die an Max-Planck-Instituten arbeiten. Mit dem vom Bundesministerium für Bildung und Forschung gestifteten Sofia Kovalevskaja-Preis zeichnet die Alexander von Humboldt-Stiftung Spitzenleistungen von jungen, ausländischen Forschern aus. Mit je 1,65 Millionen Euro können sie damit eigenständige Nachwuchsgruppen an deutschen Forschungsinstitutionen aufbauen. Eine der Preisträgerinnen ist Na Liu vom Max-Planck-Institut für Intelligente Systeme in Stuttgart.
A method that enables scientists to grow cells on easily generated fine structures provides new insights into cell migration
Whereas a cut knee often reduces children to tears, adults are more likely to be distressed by the fear of cancer. In both cases, that is wound healing and the growth and spread of tumours, a particular characteristic of the body’s cells plays a crucial role: their capacity to move in their tissue environment. Together with colleagues from Japan, scientists from the Max Planck Institute for Intelligent Systems in Stuttgart and the University of Heidelberg have developed a very promising method for the study of cell movement. The new method enables the examination of the collective behaviour of small groups of cells in an environment that imitates living tissue. Using this new method, the Stuttgart cooperative project was able to study the collective spreading behaviour of epithelial cells in the early stages of healing processes. The information gained from this study confirms the potential offered by the new method in generating new insights into cell migration, a process that has been under investigation for decades.
The Max-Planck-Gesellschaft has once again been successful in winning support from the European Research Council (ERC)
With seven Advanced Grants, the MPG is Germany’s top recipient of EU funding. In response to its fourth call for applications, the ERC conferred a total of 294 of these lucrative research awards, of which 52 went to German universities and research institutions.
Precise insight into how two microscopic surfaces slide over one another could help in the manufacture of low-friction surfaces
The problem exists on both a large and a small scale, and it even bothered the ancient Egyptians. However, although physicists have long had a good understanding of friction in things like stone blocks being pulled by workers into the shape of a pyramid, they have only now been able to explain friction in microscopic dimensions in any degree of detail. Researchers from the University of Stuttgart and the Stuttgart-based Max Planck Institute for Intelligent Systems arranged an elaborate experiment in which they pulled a layer of regularly ordered plastic spheres over an artificial crystal made of light. This enabled them to observe in detail how the layer of spheres slid over the light crystal. Contrary to what one might imagine, the spheres do not all move in unison. In fact, it's only ever some of them that move, while the others stay where they are. This observation confirms theoretical predictions and also explains why friction between microscopic surfaces depends on their atomic structure.
A heat engine measuring only a few micrometres works as well as its larger counterpart, although it splutters
What would be a case for the repair shop for a car engine is completely normal for a micro engine. If it sputters, this is caused by the thermal motions of the smallest particles, which interfere with its running. Researchers at the University of Stuttgart and the Stuttgart-based Max Planck Institute for Intelligent Systems have now observed this with a heat engine on the micrometre scale. They have also determined that the machine does actually perform work, all things considered. Although this cannot be used as yet, the experiment carried out by the researchers in Stuttgart shows that an engine does basically work, even if it is on the microscale. This means that there is nothing, in principle, to prevent the construction of highly efficient, small heat engines.
Computer dienen heute als Musikbox, Filmarchiv und Fotoalbum. Sie müssen daher immer größere Datenmengen schnell zugänglich machen. Wissenschaftler des Max-Planck-Instituts für intelligente Systeme in Stuttgart und des Hallenser Max-Planck-Instituts für Mikrostrukturphysik bereiten den Weg für magnetische Speichermaterialien, die das ermöglichen, und nutzen dabei geschickt die ganz eigenen Gesetze der Nanowelt aus. Text Christian Meier
The software enables electron microscopes to extract more information about the composition of crystals.
A new software called QED (Quantitative Electron Diffraction), which has been licensed by Max Planck Innovation, has now been released by HREM Research Inc., a Japan based company, which is developing products and services in the field of High-Resolution Electron Microscopy. QED allows transmission electron microscopes to acquire novel kinds of data, opening up new possibilities in electron crystallography.
Magnetic vortex cores, which can be used as particularly stable storage points for data bits, can now be switched much faster
Microscopically tiny ferromagnetic platelets exhibit a phenomenon which could be exploited in the future for particularly stable magnetic data storage: so-called magnetic vortex cores. These are needle-shaped magnetic structures measuring 20 nanometres (millionths of a millimetre) in diameter. Five years ago, researchers at the Max Planck Institute for Intelligent Systems (formerly the Max Planck Institute for Metals Research) in Stuttgart found a way to reverse the magnetic field needles despite their stability using only a tiny amount of energy so that their tips pointed in the opposite direction. Such a switching process is necessary to enable the vortex cores to be used in data processing. The Stuttgart scientists have now discovered a new mechanism which makes this switching process at least 20 times faster and confines it to a far smaller region than before. Magnetic vortex cores could thus provide a means of data storage which is stable, fast and greatly miniaturized.