The objective of the internship is to grow epitaxial thin multiferroic ferrite/perovskite (CoFe2(OxN1-x)4/N:BaTiO3 oxynitride films by oxygen and nitrogen plasma assisted molecular beam epitaxy: a potentially new magnetoelectric material. We will proceed by nitrogen doping of oxide films for which the growth conditions are already mastered in the CEA/SPEC laboratory. The crystalline structure as well as the magnetic and ferroelectric properties will be studied.

Novel materials are required within the energy transition and modern communication technologies frameworks, in particular to produce clean energy and/or reduce electronic device consumption and overall materials usage. Within this context oxynitrides are a relevant class of materials. The magnetoelectric ones are very well suited to realize novel multifunctional sensors. Doping by charge carriers makes it possible to envisage new transport properties. The production of hybrid single crystalline thin oxynitride films is however challenging and has been little studied to date.
We will explore the possibility of modulating the properties of thin laminar oxide magnetoelectric films of N doped cobalt ferrite (CoFe2(OxN1-x)4, ferromagnetic) deposited on nitrogen doped barium titanate (N:BaTiO3, ferroelectric). Their growth conditions are already mastered and we will proceed by the addition of nitrogen plasma during growth. We will study the influence of the N doping on the electronic, magnetic and ferroelectric properties with respect to film thickness and growth conditions. Already existing magnetic dichroism data, for some situations, will be investigated in details.

Other researchers potentially involved : Jean-Baptiste Moussy et Pâmella Vasconcelos (DES/ISAS/DRMP/S2CM/LM2T), Sylvia Matzen (C2N)