Melting of incommensurate ferroelectric phase with magnetic field in multiferroic TbMnO3

We have investigated the reentrant ferroelectric behavior of TbMnO3 under a c axis aligned magnetic field H c using neutron and x ray single crystal diffraction. We find that below TN 41 K and at high field the incommensurate ordering of Mn spins melts and coincides with the disappearance of ferroelectricity. The paraelectric phase which emerges is characterized by a simple commensurate antiferomagnetic ordering. We suggest that the reentrance of ferroelectricity at low temperatures and high magnetic field coincides with the development of incommensurate Mn and Tb spin orderin