Searches for supersymmetry in final states with a Z boson with the ATLAS detector

This talk presents searches for supersymmetry in the final state with events containing a $Z$ boson ($Z\to\ell\ell$, $\ell=e,\mu$), large missing transverse momentum and jets. Two ATLAS analyses are presented, one using a data sample of 1 fb$^{-1}$ collected at $\sqrt{s}=7$ TeV and the other using 6 fb$^{-1}$ collected at $\sqrt{s}=8$ TeV. No excesses above the Standard Model background expectation were observed. The results were interpreted in the context of a general gauge mediation (GGM) scenario, where the lightest supersymmetric particle is the gravitino and the next-to-lightest supersymmetric particle is a Higgsino-like neutralino.