In this paper we explore the possibilities given by the ac‐susceptibility &khgr;(&ohgr;), to gain information about the dynamical response of a system in the critical region. Sr3Ru2O7is known to be a strongly correlated metal with an itinerant metamagnetic first order transition, that can also be associated with a new type of quantum critical point. We study the &khgr;(&ohgr;) of this system and show that the (tuneable) finite characteristic time associated with the measurement allows us, in addition to determining the experimentalH,Tphase diagram, to get information about the dynamics of this system in the critical region. © 2004 American Institute of Physics