Phase Transitions between Magnetic Incommensurate States of Terbium Manganite in Magnetic Field

Abstract

Phase transitions between incommensurate spin states in ferroelectromagnet TbMnO3 in magnetic field along the modulation vector are phenomenologically analyzed. It is shown that the competition between different terms of the fourth order in magnetic anisotropy energy is a reason of the reorientation of spin-cycloid plane and electric polarization by 900 (polarization flop). Calculated phase diagram is in a good agreement with experimental data.