Low magnetic field reversal of electric polarization in a Y-type hexaferrite

We report on the magnetically tunable ferroelectricity and giant magnetoelectric sensitivity up to 250 K in a Y-type hexaferrite, BaSrCoZnFe11AlO22. Not only the magnitude but also the sign of electric polarization can be effectively controlled by applying low magnetic fields (a few hundreds of Oe) that modifies the spiral magnetic structures. The magnetically induced ferroelectricity is stabilized even in zero magnetic field. Decayless reproducible flipping of electric polarization by oscillating low magnetic fields is shown. The maximum linear magnetoelectric coefficient reaches a high value of similar to 3.0 x 10(3) ps/m at 200 K. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3697636]