Ferroelectricity in antiferromagnetic phases of Eu 1- xY xMnO 3

This work reports an experimental investigation of the ferroelectric character of magnetic phases of the orthorhombic Eu _{1- x}Y _xMnO ₃ system at low temperatures. The temperature dependence of the polarization curves clearly reveals the existence of a re-entrant improper ferroelectric phase for x=0.2, 0.3 and 0.5. A ferroelectric phase is also stable for x=0.4, and we have no experimental evidence for its vanishing down to 7 K. From these and early results obtained using other experimental techniques, the corresponding (x,T) phase diagram was traced, yielding significant differences with regard to the ones previously reported.