Spin Frustrated Magnets: A novel Route to Multiferroicity

The physical foundations that enable coexistence of ferroelectricity and magnetism tend to be mutually exclusive. In certain special cases where they happen to juxtapose with one another, their interaction remains exceedingly weak. But in a class of recently discovered materials, large magneto-electric effects have been discovered that are assigned to magnetism driven ferroelectricity. In these multiferroics, ferroelectric order develops upon a magnetic phase transition unto a spiral or noncollinear magnetic ordered phase. Here we review recent key experimental findings towards an understanding of spin frustrated multiferroics such as Bi2Fe4O9, Ni3V2O8 and YMnO3. We attempt to understand the origin of magneto-electric effect as deduced from in-field dielectric, specific heat and neutron scattering measurements, particularly in the light of inverse Dzyaloshinskii-Moriya (DM) correlations. We outline the key challenges in the field.