Magnetoelectricity in multiferroically composed multilayers and multiglasses

Single-crystalline magnetoelectric (ME) antiferromagnetic Cr2O3 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 Cr2O3, 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 Sr0.98Mn0.02TiO3 at low temperatures. Dipolar and spin glass orders occur simultaneously on the Mn2+ subsystem and form a multiglass by analogy with conventional multiferroics.