Singe ferroelectric and chiral magnetic domain of single-crystalline BiFeO$_3$ in an electric field

摘要

We report polarized neutron scattering and piezoresponse force microscopystudies of millimeter-sized single crystals of multiferroic BiFeO$_3$. Thecrystals, grown below the Curie temperature, consist of a single ferroelectricdomain. Two unique electric polarization directions, as well as the populationsof equivalent spiral magnetic domains, can be switched reversibly by anelectric field. A ferroelectric monodomain with a single-$q$ single-helicityspin spiral can be obtained. This level of control, so far unachievable in thinfilms, makes single-crystal BiFeO$_3$ a promising object for multiferroicsresearch.