  We report on an anomalous magnetization observed with temperature for low
magnetic fields applied in the plane of a film formed by a thin layer of Fe-Rh
deposited on a thin foil of ordered Fe$_3$Pt. The anomalous effect resembles a
metamagnetic transition and occur only in the field-cooled-cooling
magnetization curve at temperatures near 120 K. We also observe an aging effect
which broads the metamagnetic-like transition suggesting the existence of Fe-Rh
antiferromagnetic clusters which apparently are too small to be detected by the
x-ray diffraction.The X-Ray diffractogram obtained in the Fe-Rh surface of the
film do not show the Fe-Rh antiferromagnetic phase (a=2.98 $\AA$) but peaks at
same locations of those found for the pure ordered Fe$_3$Pt film (a=3.72 $\AA$)
