Each objective of MAGNUS has been pursued through a dedicated Work Package (WP). WP1 aimed at the synthesis of nanoporous ferromagnetic materials and filling of their pores with a ferroelectric polymer. During the project, porous magnetic materials have been produced mainly by two techniques: (i) electrodeposition and (ii) pulsed laser deposition. The technique (i) allowed fabricating porous alloys and metals, such as macroporous FeGa and mesoporous Ni and Co. In some cases lithography methods were used to pattern the substrates. The technique (ii) was used to grow cobalt ferrite (CFO) nanoporous films and, in fact, involved a two-step procedure where a vertically alighted composite of CFO:MgO was first grown by pulsed laser deposition and the nanoporous CFO structure was achieved by etching away sacrificial MgO phase of the as-grown composite. Porous CFO matrices have been filled with ferroelectric polymer (PVDF) employing either spin-coating or electrophoretic deposition protocols depending on the size of the pores in the porous matrix.
WP2 was focused on the investigation of structural, mechanical and magnetoelectric properties of the obtained composite materials. This WP brought significantly interesting results in all aspects. In terms of structural characterization, a novel methodology for measuring magnetostriction in nanoporous materials has been proposed. In terms of mechanical characterization, an in-depth nanoindentation analysis of macroporous FeGa alloys has been performed to unveil the role of porosity on mechanical, magnetic and magnetostrictive properties of the matrix. Finally, a comprehensive study of magnetoelectric properties of the composites has been performed employing both liquid and solid composite configurations.
WP3 targeted at the exploitation of the fabricated composites: (i) wireless cell stimulation, and (ii) energy-efficient writing of magnetic information. The former task has been achieved using bone cells Saos-2 that were magneto-electrically stimulated to increase the proliferation employing the composite materials developed in WP1. The former task has not been fully achieved due to failure of the ferroelectric counterpart.
The merged results from WP1 and WP2 resulted in six peer-reviewed papers published in high impact journals. One of the publications represents a perspective on the strain-gradient effects in nanoscale-engineered magnetoelectric materials, and another one is an encyclopedia entry on nanoporous composites with converse ME effects for energy-efficient applications. At the moment of presenting the final report, two more publications that include the main results on the WP3 are being prepared. The project results have been presented at 4 international conferences and webinars, and disseminated though a seminar for young ITN ESRs, audiovisual materials (video and manuals) and through a dedicated web-page. It is worth mentioning that some of the talks and protocols/manuals resulted from the project are fully accessible on Zenodo data repository platform.
