  We present magnetization studies in a series of phase separated
La$_{0.5}$Ca$%_{0.5}$MnO$_{3}$ samples, with different low temperature
fractions of the ferromagnetic (FM) and charge ordered-antiferromagnetic
(CO-AFM) phases. A particular experimental procedure probes the effect of the
magnetic field applied while cooling the samples, which promotes FM fraction
enlargement and enhances the melting of the CO phase. The response of the
system depending on its magnetic field history indicates the existence of three
different regimes in the phase separated state which develops below T$_{C}$.
Our data allows us to identify the onset temperature below which the system
becomes magnetic and structurally phase separated, and an onset field above
which FM fraction enlargement occurs.
