A new promising approach are core-shell type ceramics where a magnetoelectric composite is formed in-situ during synthesis. In the system (BiFe 0.9 Co 0.1 O 3) 0.4 -(Bi 1/2 K 1/2 TiO 3) 0.6 (BFC-BKT) very strong ME coupling has been observed on a microscopic scale using PFM under magnetic field. Furthermore, switching of magnetization via electric field has been observed using MFM. Here, the ME active core-shell grains consist of magnetic CoFe 2 O 4 (CFO) cores and a (BiFeO 3) 0.6 -(Bi 1/2 K 1/2 TiO 3) 0.4 (BFO-BKT) shell where core and shell have an epitaxial lattice structure. The mechanism of strong ME coupling is via magnetic exchange interaction between CFO and BFO across the core-shell interface, which results in an exceptionally high Neel-Temperature of 670 K of the BF-BKT phase.