Lay summary
Ferroelectric magnets remain at the forefront of research because of promising important applications and due to the rich physics involved. We propose to investigate a new route allowing to achieve a strong coupling between magnetism and ferroelectricity. We want to link frustrated low-dimensional magnetic units with d^n ions by exchange bridges with d^0 ions possessing polarizable lone-pair electrons. Two systems are in our focus: layered geometrically frustrated cluster FeTe2O5Br compound and Kagome-like francisite Cu3Bi(MO3)2X (M=Te, Se, X= Cl, Br, I). The first steps in the investigation of FeTe2O5Br delivered very interesting results and need to be continued. The information on Cu3Bi(MO3)2X is limited, but promising. We plan to extend it by bulk measurements, x-ray and neutron scattering.