Objectives and Research Lines

DAFNEOX (Designing Advanced Functionalities through controlled NanoElement integration in OXide thin films) is a Marie Skłodowska-Curie Research and Innovation Staff Exchange (RISE) action funded by European Commission through H2020-MSCA. Our project brings together experts in experimental and theoretical physics including materials science and advanced electronic/spectroscopic expertise and one spin-off with the goal to develop new inexpensive, scalable and efficient bottom –up approaches for positioning nanoobjects in regular patterns and to implement them in optoelectronic or catalysis technologies. The objectives of DAFNEOX are linked to those of MSCA and RISE Actions for the development of Europe’s intellectual capital:

  • To create new collaboration or strength existing ones among involved organisations
  • To generate new skills, knowledge and innovation
  • To allow transition of knowledge into innovative products bridging Academia and Non-Academia sectors

Design and Fabrication of Nanostructures

 

 

Our main goal is obtaining spontaneous nanostructured templates of various functional oxides by bottom-up approach for guided self-assembly of nanoelements. Our strategy combines at the same time the unusual misfit strain relaxation behaviour of perovskite oxide thin films (due to different substrate-film lattice mismatch) in a kinetically limited regime and the influence of regular arrangement of atomic steps on a mesoscopic scale of underlaying vicinal substrates on surface mobility, promoting the long-range order. Since functional properties of nanoelements are highly dependent on the size, shape, crystallinity and surface state, their controlled synthesis with a narrow size distribution and uniform shape is a very relevant issue.

 

Advanced transport characterisation

 

The main goal is to study the charge transport of single (or few) nanoparticles with intrinsic opto-electronic and spin properties, and evaluate their behaviour upon use of external stimuli such as gate, light and magnetic field. We compare the performance of the devices upon changes in a nanoparticle size, which might lead to an optimal size value for a device with maximum performance. Different set-ups are suitable for the ,easurements of the charge transport of single nanoparticles: two-terminal Mechanically Controllable Break Junction Technique and three-terminal electromigrated and self-aligned devices. Depending on functionalities of nanoparticles we are interested in the influence of gate, light and magnetic field on the charge transport in single nanoparticles. The central question that we would like to address is whether we can control the intrinsic functionalities of single nanoparticles using external stimuli. Local electrical transport properties in self-assembled magnetic nanoparticles on top of oxide thin film are studied by to elucidate the mechanism of two-terminal hysteretic resistive switches in one dimensional nanostructures.

 

Advanced Functional Properties

 

A broad range of spectroscopic methods are employed to obtain a complete picture of the physical behaviour of each state. Our objective is to identify the physical mechanisms and relevant parameters through which the sample preparation may be controlled.
Raman scattering spectroscopy is one of the most commonly used and powerful techniques for characterization of nano-sized materials and structures. By analysing optical mode shift, broadening and lineshape it is possible to obtain information regarding various effects in nanomaterials, such as particle size distribution, strain, substitutional effects, defect states and nonstoichiometry, electron-phonon coupling Novel and/or enhanced physical properties may be explored by advanced magnetic characterization to understand the physical mechanisms of magnetization dynamics and the MAMR response in different materials. We focus on; (i) Understanding the effect of the geometry on the dynamic magnetic properties response in self-assembled magnetic nanoparticles and the role of defect structures (ii) magnetization reversal studies of exchange-coupled composites in both magnetic nanoparticles and thin films. (iii) Study of magnetization reversal under the effect of a microwave field in new materials such as coupled composites or exchange spring materials with high magnetic anisotropy.

 

Theory and Simulation

 

The interplay between local kinetic processes and a simultaneously occurring phase transition or the elastic interaction between the film and substrate, modelized by non-local equations of the reaction diffusion type, may provide a suitable mechanism for spontaneous self-organization in the atomic deposition with sizes lying in the nanometer range. Our first primary goal is to establish a continuous macroscopic model that account spontaneous self-organized oxide nanotemplates. On the other hand, the attachment of the nanoelements to the surface, determined by the atomistic details of the functional groups of the nanolement and by the atomistic details of preferable binding sites will be performed using Density Functional Theory (DFT) total energy calculations, i.e. without the introduction of any fitting or phenomenological parameters. Based on this work we aim to develop and parameterize a classical force field model of the interaction of nanoelements with the surface that will allows us to simulate the process of nanoelement binding to the surface.