Magnetic Ordering in Multiferroics Eu0.3Y0.7MnO3.

The recent interest in the study of perosvkite-manganite RMNO3 (with R=rare earth) is due to the observation of the ferroeletric transitions that are concomitant with complex ordering of Mn 3d spins. In order to clarify the correlation between the magnetic transitions of the Mn 3d spins with the ferroelectric transition, we investigated the magnetic structure of the perovskite Eu0.7Y0.3MnO3 without the influence of the 4f magnetic moment of the rare earth ion. It was observed, below 30 K, a cycloid magnetic structure in the ab plane which drives the emergent ferroelectricity via the antisymmetric Dzyaloshinski-Moriya interaction.This magnetic ordering provides the magnetic origin for the ferroelectricity polarization parallel to the a-axis.Moreover, between 30 and 50 K, an additional magnetic phase with a collinear sinusoidal magnetic structure was observed.