A recent experiment on the multiferroic BiMn2O5 compound under a strong applied magnetic field revealed a rich phase diagram driven by the coupling of magnetic and charge (dipolar) degrees of freedom. Based on the exchange-striction mechanism, we propose here a theoretical model with the intent to capture the interplay of the spin and dipolar moments in the presence of a magnetic field in BiMn2O5. Experimentally observed behavior of the dielectric constants, magnetic susceptibility, and the polarization is, for the most part, reproduced by our model. The critical behavior observed near the polarization reversal (P=0) point in the phase diagram is interpreted as arising from the proximity to the critical end point.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|State||Published - 1 Mar 2009|