3:1 magnetization plateau and suppression of ferroelectric polarization in an Ising chain multiferroic

Ferroelectric Ising chain magnet Ca3Co2-xMnxO6 (x similar or equal to 0.96) was studied in magnetic fields of up to 33 T. Magnetization and neutron-scattering measurements reveal successive metamagnetic transitions from the zero-field up arrow up arrow down arrow down arrow spin configuration to the up arrow up arrow up arrow down arrow state with a broad magnetization plateau, and then to the up arrow up arrow up arrow up arrow state. The absence of hysteresis in these plateaus reveals an intriguing coupling between the intrachain state and the three-dimensional geometrically frustrated magnetic system. Inversion symmetry, broken in the up arrow up arrow down arrow down arrow state, is restored in the up arrow up arrow up arrow down arrow state, leading to the complete suppression of the electric polarization driven by symmetric superexchange.