Multiferroic heterostructures consisting of Pb(Zr0.52Ti0.48)O-3 and Fe0.7Ga0.3 thin films are integrated on microfabricated Si cantilevers, and they are operated in a non-linear regime. Enhanced mechanical coupling at the multiferroic interface and tunability of the resonant frequency are used to devise bistable dynamic states that can be reversibly switched by both DC magnetic and electric fields.