Magnetic field induced flop of cycloidal spin order in multiferroic TbMnO3: The magnetic structure of the P||a phase

摘要

Using in-field single crystal neutron diffraction we have determined themagnetic structure of TbMnO3 in the high field P||a phase. We unambiguouslyestablish that the ferroelectric polarization arises from a cycloidal Mn spinsordering, with spins rotating in the ab plane. Our results demonstrate directlythat the flop of the ferroelectric polarization in TbMnO3 with applied magneticfield is caused from the flop of the Mn cycloidal plane.