1D Nanostructures of tethered piezoelectric and magnetic phases:
Top-down technologies will be used to fabricate self-standing 1D nanostructures of magnetostrictive cobalt-alloys and ferrites on a substrate. The subsequent filling of the spacing between the 1D nanostructures leads to tethered phases with the huge interfacial area that could result in the remarkable magnetoelectric coupling. In particular, these technologies include:
Processing of magnetic nanopowders and their functionalization:
Design of magnetic nanorods in a piezoelectric-matrix:
Deposition of magnetostrictive nanostructures:
Embedding the magnetostrictive nanostructure into the piezoelectric phase
1D Ferroelectric nanorods
We seek a way to achieve a self-assembled vertically aligned nanocomposite, comprised of a spatially ordered, hierarchical structure of ferroelectric nanorods set within a dielectric matrix, for example, BaTiO3 in SrTiO3, each of which would contain a topological ferroelectric texture such as a skyrmions or vortices that could be controlled by an electric field. The innovative experimental challenge here will be achieving the length scales if nanometric dimensions are essential. To arrive in the desired structures we shall proceed to synthesis by three different techniques. Template-Assisted Syntheses with the sol-gel assisted confinement.
Piezoelectric/magnetic epitaxial superlattices
The objective of this part is the design and synthesis of piezoelectric/magnetic and ferroelectric/magnetic bilayer- and multilayer nanostructures built up from alternating piezoelectric (or ferroelectric) and magnetic layers to optimize the magnetoelectric interlayer coupling. These nanostructures will be produced using the magnetic and piezoelectric materials. The piezoelectric/magnetic bilayers will be elaborated through two approaches. In the first approach, we shall use the PLD method to provide a controlled growth of the perovskite films aiming at producing highly textured or even completely epitaxial layers, whereupon the desired properties are tailored via tuning thermal and lattice mismatch stresses. The second approach will be to use Chemical Solution Deposition route (sol-gel) to prepare polycrystalline films. For both approaches, the processing-structure-properties relationships will be established with respect to the multifunctional properties indicated above. We will find also the best processing and post-annealing conditions that will result in optimum functional properties, e.g. high sensitivity of films and bi/multilayers to external fields, high magnetostriction and electrostriction, high spontaneous magnetization and polarization, and multicaloric cooling.
