Emergence of a “devil’s staircase” in a spin-valve system
Hexagonal single crystal of SrCo6O11, with a sample diameter of approximately 0,2 millimetres.
The material exhibits distinct magnetization plateau connected with different spin configurations.
A Japanese-German team observes at BESSY II how spins form unusual magnetic structures in a complex cobalt oxide single crystal. Such a material offers new perspectives for spintronic applications.
While classical GMR systems are composed of metallic layers, complex oxides often intrinsically provide layered structures with alternating magnetic configurations that can act as spin valves. Cobalt oxides are a class of materials that can exhibit complex magnetic order that changes with increasing magnetic field, as for example indicated by distinct plateaux in the magnetization curve.
Magnetic structures mapped
A Japanese team of researchers led by the group of Associate Professor Hiroki Wadati at the University of Tokyo has been successful in characterizing the magnetic structures of the complex cobalt oxide SrCo6O11 using the high-field diffractometer of BESSY II. Synthesis of new materials often results in tiny samples, and the crystals studied here had a diameter of only 0.2 mm. With the very high sensitivity of resonant diffraction, a core competence at the UE46_PGM1 beamline of BESSY II, they managed to observe a fascinating type of spin order in the samples that are hardly visible by the bare eye. This order is called devil’s staircase, characterizing a phenomenon, where a pletora, in principle even an infinite number, of so-called commensurate superstructures - magnetic configurations in the present case - can be realized by tuning an external parameter, e.g., a magnetic field.
New options with a Devil's staircase
This exceeds the characteristic of a spin valve and may open new paths in spintronics. The research was carried out in close cooperation with German scientists from the Institut für Festkörper-und Werkstoffforschung Dresden and HZB. The results are now published in Physical Review Letters.
Reference: T. Matsuda, S. Partzsch, T. Tsuyama, E. Schierle, E. Weschke, J. Geck, T. Saito, S. Ishiwata, Y. Tokura, and H. Wadati, "Observation of a Devil’s Staircase in the Novel Spin-Valve System SrCo6O11", Physical Review Letters 114 (236403-1-5):
doi:10.1103/PhysRevLett.114.236403.
- Small powerhouses for very special lightAn international team presents the functional principle of a new source of synchrotron radiation in Nature Communications Physics. Steady-state microbunching (SSMB) allows to build efficient and powerful radiation sources for coherent UV radiation in the future. This is very attractive for applications in basic research as well in the semiconductor industry.
- New Method for Absorption Correction to Improve Dental FillingsA research team led by Dr. Ioanna Mantouvalou has developed a method to more accurately depict the elemental distributions in dental materials than previously possible. The used confocal micro-X-ray fluorescence (micro-XRF) analysis provides three-dimensional elemental images that contain distortions. These distortions occur when X-rays pass through materials of different densities and compositions. By utilizing micro-CT data, which provides detailed 3D images of the material structure, and chemical information from X-ray absorption spectroscopy (XAS) experiments conducted in the laboratory (BLiX, TU Berlin) and at the synchrotron light source BESSY II, the researchers have improved the method.
- Helmholtz Institute for Polymers in Energy Applications (HIPOLE Jena) InauguratedOn June 17, 2024, the Helmholtz Institute for Polymers in Energy Applications (HIPOLE Jena) was officially inaugurated in Jena in the presence of Wolfgang Tiefensee, Minister for Economy, Science, and Digital Society of the Free State of Thuringia. The institute was founded by the Helmholtz Center Berlin for Materials and Energy (HZB) in cooperation with the Friedrich Schiller University Jena. It is dedicated to developing sustainable polymer materials for energy technologies, which are expected to play a key role in the energy transition and support Germany’s goal of becoming climate-neutral by 2045.