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

Abstract

Ferroelectric Ising chain magnet ${\text{Ca}}_{3}{\text{Co}}_{2\ensuremath{-}x}{\text{Mn}}_{x}{\text{O}}_{6}$ $(x\ensuremath{\simeq}0.96)$ was studied in magnetic fields of up to 33 T. Magnetization and neutron-scattering measurements reveal successive metamagnetic transitions from the zero-field $\ensuremath{\uparrow}\ensuremath{\uparrow}\ensuremath{\downarrow}\ensuremath{\downarrow}$ spin configuration to the $\ensuremath{\uparrow}\ensuremath{\uparrow}\ensuremath{\uparrow}\ensuremath{\downarrow}$ state with a broad magnetization plateau, and then to the $\ensuremath{\uparrow}\ensuremath{\uparrow}\ensuremath{\uparrow}\ensuremath{\uparrow}$ 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 $\ensuremath{\uparrow}\ensuremath{\uparrow}\ensuremath{\downarrow}\ensuremath{\downarrow}$ state, is restored in the $\ensuremath{\uparrow}\ensuremath{\uparrow}\ensuremath{\uparrow}\ensuremath{\downarrow}$ state, leading to the complete suppression of the electric polarization driven by symmetric superexchange.