Multiferroic nanoregions and a memory effect in cupric oxide

Abstract

We report the observation of multiferroic nanoregions in cupric oxide, CuO, by means of resonant soft x-ray magnetic scattering. There exists an anomalous memory effect for the direction of the electric polarization in the commensurate-incommensurate magnetic transition that coincides with the ferroelectric transition. Scattering results, incorporated with simulations of diffuse scattering, lead us to propose a scenario that preserved spin handedness in the multiferroic nanoregions is responsible for this memory effect in the magnetically induced ferroelectric properties of CuO.