Magnetic garnet Y3Fe5O12and magnetic ferrite BaFe12O19have been irradiated at room temperature by Kr and Xe ions using the GANIL accelerator at Caen and by U ions using the Unilac accelerator at Darmstadt. These experiments allow to cover a wide range of electronic stopping power values (between 7 MeV/μm and 45 MeV/μm) using the ion beam at energy between 40 MeV/a.m.u. and 8 MeV/a.m.u. Transmission Mössbauer spectrometry has been used to determine the damage cross section A for the corresponding value of electronic stopping power. High resolution electron microscopy observations confirm the A determination for the highest value of dE/dx. The main feature is the appearance of a saturation in the damage efficiency ϵ =A/dE/dxabove an electronic stoping power valueTM. Using all the previous results, damage evolution and damage morphology description will be proposed and comparison with the chemical etching sensitivity of the magnetic garnet will be done.