Magnetoelectric effects in multiferroic manganites

A variety of bulk as well as local magnetoelectric effects are observed in RMnO3 compounds with R=Sc,Y,In,Ho,Er,Tm,Yb,Lu due to the coexistence of ferroelectric and multiple magnetic ordering. On the one hand, 'gigantic' magnetoelectric bulk effects, where magnetic phase control is exerted by applied electric or magnetic fields, are revealed. On the other hand, interaction of domain walls leads to a coupling of ferroelectric and antiferromagnetic domains, and a contribution to the linear magnetoelectric effect that is induced in the antiferromagnetic domain walls is identified. The effects are observed by linear and nonlinear magnetooptical techniques and explained microscopically by the interplay of magnetic exchange, wall magnetization, and ferroelectric distortion.