Magnetoelectricity in multiferroically composed multilayers and multiglasses

Single-crystalline magnetoelectric (ME) antiferromagnetic Cr 2O 3 exchange coupled to a ferromagnetic multilayer (Pt/Co/Pt) n , n⩾1, represents a multiphase multiferroic material with sophisticated multifunctional properties. They comprise the possibility of switching the exchange bias (EB) of the ferromagnetic hysteresis loop via the linear ME effect of Cr 2O 3, and to design MERAM and logic cells operating at room temperature. Quadratic and cubic ME effects – promoted by soft-mode quantum fluctuations – are observed at lowest order in ceramic Sr 0.98Mn 0.02TiO 3 at low temperatures. Dipolar and spin glass orders occur simultaneously on the Mn 2+ subsystem and form a multiglass by analogy with conventional multiferroics.