Phase coexistence and magnetically tuneable polarization in cycloidal multiferroics

In some magnetic ferroelectrics the polarization P direction can be selected by a magnetic field H. Here we show that in a (Y1-xSm x)MnO3 single crystal, both the direction and the magnitude of P can be controlled solely by H. We argue that this remarkable dual control arises from both the phase coexistence of bc-cycloidal regions within an ab-cycloidal matrix and the annihilation of multiferroic domain walls by H cycling. We show that phase coexistence occurs even within the high-temperature spin-collinear phase and argue that this could be a general property arising from the strong frustration of magnetic interactions in these oxides. © 2013 American Physical Society.