  A method for estimation of reversible and irreversible susceptibilities of
initial magnetization curves has been developed. It deals only with the energy
necessary for magnetizing and demagnetizing the sample, not with the nature of
the magnetization processes neither with a specific type of anisotropy, so it
could be applied for a wide variety of real materials. A set of minor
hysteresis loops of an initially demagnetized sample, plotted with
progressively increasing maximum magnetic field, has been used. The obtained
results showed an excellent coincidence with those calculated by the remanence
curve method for a Stoner-Wohlfarth model system.
