Ferroelectricity of Rare Earth Manganese Oxide RMn₂O₅

抄録

  Rare earth manganites RMn₂O₅(R=Nd−Lu, Y or Bi) have been revealed ferroelectric at low temperatures. The spontaneous polarization is along the b-direction of the orthorhombic crystal. The ferroelectric Curie temperature is between 25 K and 39 K, apparently depending on the total orbital quantum number L of the rare earth ion. In several oxides of the series, another phase transition is present at lower temperature, accompanying an remarkable change in spontaneous polarization.