Dr. Raul Garcia Diez wins the Dissertationspreis Adlershof 2017
Dr. Raul Garcia Diez was awarded for his PhD Thesis with the Dissertationspreis Adlershof 2017.
Jury with nominees and the winner, Dr. Raul Garcia Diez, (left), Photo: Matthias Brandt
With his talk on the properties of nanoparticles and how they can be measured more accurately at BESSY II, Dr. Raul Garcia Diez convinced the jury and was awarded the Dissertationspreis Adlershof 2017. Humboldt-Universität zu Berlin, IGAFA e. V. and the WISTA MANAGEMENT GmbH are the sponsors of this prize endowed with 3000 Euros. Garcia Diez completed his PhD in 2017 at PTB and TU Berlin and is now active as a post-doctoral researcher at HZB.
The use of nanoparticles in medicine is continuously growing, for example as platforms for drug-delivery or encapsulating imaging agents. In order to tailor nanoparticles for these applications, the functional properties of these particles need to be well understood.
In his thesis on "Characterization of Nanoparticles by Continuous Contrast Variation with Small-Angle X-ray Scattering" Raul Garcia Diez developed a method to study nanoparticles in a realistic environment with X-ray small-angle scattering in order to gain valuable information. The work was carried out with the HZB SAXS instrument, which is operated at the FCM beamline of the Physikalisch-Technische Bundesanstalt (PTB) in BESSY II under the cooperation between PTB and HZB.
With his work at PTB with Prof. Matthias Richter, he obtained his PhD title in May 2017 at the TU Berlin. Since then, Garcia Diez is a postdoctoral fellow with Prof. Marcus Bär at the HZB.
- Magnetic imaging: Micro-flowers increase the local magnetic fieldMaterials with magnetic nanostructures have many potential applications such as in spintronics. To explore such materials, nanoscale magnetic-sensitive imaging techniques are very useful, but up to now only weak magnetic fields could be applied during the imaging process. Now an international collaboration led by Dr. Sergio Valencia, HZB, has developed an approach that overcomes this limitation. The team designed tiny magnetic flux concentrators (MFCs), into which the sample is placed. The geometry of the MFCs resembles a flower with a number of petals which focus the applied magnetic field into its center. This greatly expands the magnetic field range available during imaging, and so the range of magnetic systems that can be investigated. The micro-flowers, enhancing magnetic fields locally, can find application in different nanometric magnetic microscopy techniques.
- Disorder creates new properties in compound semiconductorsAn international research team has demonstrated that the intrinsic disorder of the compound semiconductor CuInSnS₄ can be exploited to influence its optical properties. While the atomic vibrations also sense the local disorder, their response is averaged over many different local environments and therefore appear isotropic, as expected for a cubic crystal. In contrast, the optical excitations, known as excitons, are much more sensitive to the local arrangement of atoms. Surprisingly, they show a direction-dependent optical response even though the average crystal structure is cubic. These findings shed new light on the relationship between disorder and material properties, opening up new options for targeted 'disorder engineering' in optoelectronic and photocatalytic devices.
- Superconducting TES array X-ray spectrometer goes into operation at BESSY IIEurope's first and only TES-spectrometer at a synchrotron source is now in operation at BESSY II, developed within a collaboration between the HZB, the MPI-CEC (Mühlheim-an-der-Ruhr, Germany) and the NIST (Boulder CO, USA). The photon detection efficiency of the new instrument exceeds that of wavelength-dispersive X-ray emission spectrometers by a factor of 100 to 1000. It will be used to investigate the electronic properties of atomically thin layers, nanostructures and highly diluted atomic and molecular samples. The team is looking forward to receiving exciting research proposals from the user community.