Propiedades térmicas y transiciones de fase en la nanoescala

The aim of this project is the study of the thermal properties and the thermodynamic and kinetic parameters that play a key role during phase transitions in thin, ultrathin films or nanostructured materials with the goal to improve their properties for a future use of the material. To realize these objectives we will develop new calorimetric chips by microfabrication tools and specific instrumentation to measure the heat capacity with a high resolution and we will extend the calorimetric technique to allow for high-throughput screening of materials. Within this innovative approach we expect to contribute to increase the general knowledge of the scientific community regarding the influence of the lower dimensionality on the materials properties. In particular, we will analyze the amorphous-to-liquid transition and the growth of nanocrystals in ultrathin films (1-5 nm) of Ge embedded in a SiO2 matrix and the relevant kinetic and thermodynamic parameters in the formation of intermediate phases in the NiSi system at heating rates compatible with microelectronics processing and not accessible with conventional calorimetry. The high sensitivity achieved so far will permit the study of phase transitions of higher order as the ferro-paramagnetic transition in ultrathin films of Ni (1-10 nm). The development of multiparallel calorimetry will facilitate the analysis of binary or ternary alloys of FePt with minor addition of Cu, Ag or Au to ascertain the influence of the thickness and composition on the order/disorder transition. We will also examine if the grain size has a beneficial effect in the enthalpy of formation of MgH2. We will analyze the kinetic factors that favour preparation and thermal stability of new soft-magnetic Fe-based materials with improved magnetic properties due to their nanocrystalline structures and the cross-plane thermal conductivity in quantum wells and nanoestructrures of the SiGe family (...)