CORDIS - EU research results

Manipulating the coupling in multi-ferroic thin Films

Final Report Summary - MACOMUFI (Manipulating the coupling in multiferroic thin films)

Multiferroic (MF) thin films constitute single phase material layers which exhibit more than one ferroic properties simultaneously, such as Ferromagnetic (FM) and Ferroelectric (FE) properties. On the other hand, Magnetoelectric materials (ME) exhibit coupling between the ferroelectric and magnetic degrees of freedom so that an electric field would induce a magnetic polarisation and vice versa. Not all multiferroics are magnetoelectric materials, nonetheless the ME coupling is greater in MF materials and enables the design and development of novel devices

The aim of the project was to Manipulate the coupling in multiferroic thin films (MACOMUFI) in order to enhance the potential of certain electronic devices, namely enable the electric tuning of ferromagnetic resonance of Radio frequency (RF) filters or the tuning of ferromagnetic resonance of the spin wave excitations in Magnetic spin wave (MSW) devices. The project had also the following objectives:
- Deployment of novel tools in order to characterise the structure of multiferroic thin films;
- Deployment of non-linear methods in order to investigate the coexistence of magnetic and electric orders as well as their coupling (magnetoelectric coupling) by means of strain engineering;
- Development of new multiferroic materials such as orthorhombic perovskite thin films as well as composite ones;
- Control of the dielectric losses in multiferroic materials by selection of the proper size of thin films.

The project achieved in demonstrating the ferroelectric properties of the barium titanate (BaTiO3) thin film, which constitutes a barrier in tunnel junctions and the electric polarisation of which can lead to tunnel junctions with high electroresistance. Furthermore, it demonstrated, in room temperature, that the electric field induced a magnetic polarisation in certain multiferroic nanocomposite thin films.