Y3Fe5O12samples have been irradiated by Kr ions with incident energies between 9 and 37 MeV/A and Xe ions between 9 and 25 MeV/A. In this way a range of electronic stopping power between 7 and 28 MeV/&mgr;m has been explored. The irradiated samples have been etched chemically. A homogeneous track etching radius is observed after xenon irradiation but not after krypton irradiation. This result indicates that at an electronic stopping power value (dE/dx) of 17±3 MeV/&mgr;m a change in the damage morphology occurs: above this value the latent track becomes continuous cylinder. This value of stopping power is markedly higher than thedE/dx(8±1 MeV/&mgr;m) at which we have previously observed a change in the latent track damage rate and in the damage morphology from spherical to cylindrical shape of the defects.