Our aim in this proposal is to investigate and map the metamagnetic critical end point in the frustrated multiferroic BiMn2O5, which exhibits a complex magnetic interactions [5,6]. RMn2O5 (R being a rare earth or Bi and Y) is an interesting class of multiferroic materials due to the physics phenomena involved, their large dieletric response under magnetic fields [6]. The greatest technological appeal is that this phenomenon should allow for applications of such materials in fast-access and non-volatile memory devices, besides a wide variety of novel environmental sensors [1]. To performed this task, we intend to follow the magnetic reflection (0.5 0 1.5), applying magnetic field along the a-axis, for temperatures below the magnetic transition (40K), in order to observe and understand the spin arrangement of the Mn moments of this system in high magnetic fields.