Personal web page : http://iramis.cea.fr/Pisp/francoise.damay/
Laboratory link : http://www-llb.cea.fr/
The general context of this PhD work is the search for new multiferroics, compounds in which magnetisation and electric polarization are coupled, allowing for instance a magnetic field to modify the polarization, of an electric field to change magnetization.
In the proposed work, a new family of promising multiferroics will be investigated, namely niobiates and tantalates of general formula A4A'O9 with A a divalent transition metal. In work published in 2018, it was shown that in particular Fe4Ta2O9 exhibits both multiferroic and linear magneto-electric properties, depending on the temperature range. This suggests different spin/charge couplings that remain to be explored and understood. Experimental techniques will be devoted to the understanding of the relations ships between crystal and magnetic structures and physical properties: for the most part, the student will deal with magnetization, dielectric constant and polarization measurements, coupled with X-ray and neutron diffraction experiments versus temperature.