TEM analysis of ion tracks and hillocks produced by swift heavy ions of different velocities in Y3Fe5O12

The size of ion tracks and hillocks produced during heavy ion irradiation of Y3Fe5O12 is analyzed by transmission electron microscopy. The cross sections of hillocks and ion tracks produced by ions with electronic stopping power Se in the range of 20–35 keV/nm are found to be comparable. In this range, the characteristic dimensions of the hillocks (both cross section and height) increase as a function of Se. The data show that there is a correlation between hillock height and hillock cross section, which is linked to the relation between lifetime of the melt along the ion trajectory and the maximum molten area. In addition, the results clearly show that the size of the hillocks produced by low velocity ions is larger than those produced by high velocity ions of the same Se, due to the so-called velocity effect.The size of ion tracks and hillocks produced during heavy ion irradiation of Y3Fe5O12 is analyzed by transmission electron microscopy. The cross sections of hillocks and ion tracks produced by ions with electronic stopping power Se in the range of 20–35 keV/nm are found to be comparable. In this range, the characteristic dimensions of the hillocks (both cross section and height) increase as a function of Se. The data show that there is a correlation between hillock height and hillock cross section, which is linked to the relation between lifetime of the melt along the ion trajectory and the maximum molten area. In addition, the results clearly show that the size of the hillocks produced by low velocity ions is larger than those produced by high velocity ions of the same Se, due to the so-called velocity effect.