Executive Summary : | Current research in magnetoelectric ferroelectrics focuses on searching new materials, which exhibit ferroelectric order at higher temperature with a strong magnetoelectric coupling. In addition to the fundamental interests, these materials are promising for diverse areas of applications viz., actuators, switches, magnetic field sensors and new types of spintronic memory devices. For the last two applications, the magnetoelectric coupling is desirable in ferroelectrics. Till the date, BiFeO3 is the top celebrated compound, where multiferroic order is observed much above the room temperature having a large spontaneous electric polarization. BiFeO3 is a type-I multiferroics and weak magnetoelectric coupling is a major drawback of this compound for the practical applications. Type-II multiferroics, where magnetic order directly or indirectly promotes the ferroelectric order, typically exhibits much stronger magnetoelectric coupling. Unfortunately, most of the spin driven ferroelectric order occurs at lower temperatures. Typically, breaking of time reversal symmetry is needed for magnetic order, whereas ferroelectricity appears involving breaking of space inversion symmetry. Thus, concomitant occurrence of breaking of both time reversal symmetry and space inversion symmetry has been rarely found in a chemically single-phase compound. Recent advancement in the field proposes that structural distortions driven by several factors such as geometric magnetic frustration, Jahn-Teller distortion driven orbital order, short range magnetic order often favours for improving these promising properties at higher temperatures. The detailed studies in this area need to be explored both theoretically and experimentally. Current proposal is focused on searching improved magnetoelectric ferroelectrics at higher temperatures and understanding the origin behind such unusual concomitant occurrence of ferroelectric and magnetic order in a chemically single-phase compound having considerable magnetoelectric coupling. |