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Thesis available (2013-2014) at the laboratory LAMPS |
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1) Magnetic properties of nanostructured materials. The study of nano systems is a hot topic for fundamental physics and for advanced technology applications. The thesis will cover the experimental characterization of nano-structured magnetic materials based on iron and cobalt. The study will be focused on ac susceptibility measurements characterizing the magnetic multi-harmonic response vs. temperature, dc magnetic field and frequency of the ac magnetic field. The main goal will be the identification of magnetic metastable phases due to the different processes of synthesis of nano-particles and the critical size below which they show the super-paramagnetic or the spin glass phase. The analysis will be performed with the use of models that take into account of parameters such as the magnetic anisotropy K, the distributions of the size of the grains, the temperature of blocking and/or the spin glass temperature. 2) Magnetic properties of layered semiconductors with a large spin-orbit interaction Emerging photonics applications require the synthesis of new semiconductor and insulating materials with greater flexibility and unique properties. The thesis will concern the study of insulating materials characterized by a strong spin-orbit interaction by means of the magnetic multi-harmonic susceptibility as a function of temperature, the dc magnetic field and the frequency of the ac magnetic field. We will study in particular the mechanisms that determine the standard diamagnetic response and the eventual paramagnetic response modulated by temperature, magnetic field and the density of carriers present in the semiconductor material. 3) Superconducting and magnetic phases in HTSC systems: possible correlation among nanoscopic phases The discovery of new high-temperature superconductor materials is again driving the research in an area with a strong technological impact and of great interest for the energy. The thesis will deal with the open problem of the coexistence of superconductivity and magnetism. The study of the magnetic multi-harmonic susceptibility can discriminate the presence of different phases as a function of the temperature and of the magnetic field. In particular, the behavior as a function of the frequency may clarify the nature and type of the different phases present in HTSC materials.
Tutors: Prof. Augusto Marcelli (INFN/LNF & USTC - Chinese Academy of Science) |
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