Shape-dependent magnetoelectric coupling in nanoscale BiFeO3

The nanorods and nanocuboids of multiferroic BiFeO3 exhibit remarkable shape dependence of crystallographic, ferroelectric, and magnetoelectric properties. The nanorods, for example, assume R3m space group (as against R3c observed both in bulk and nearly spherical nanosized particles) and are found to be oriented preferentially with long axis ∥ [101]. The magnetic and electric coercive fields as well as magnetoelectric coupling - measured from change in remanent polarization under a magnetic field - are found to be larger in nanocuboids. The shape dependence of multiferroic properties originates from that of microstrain and anisotropy.