Identical response of insulators to irradiations by swift heavy ions: application to experiments on Gd2Ti2O7.

Track radii Re induced by swift heavy ions are studied. The experimental track data are analyzed in Gd2Ti2O7 pyrochlore in the range Se=6-54 keV/nm (Se - electronic stopping power) including irradiations by low and high velocity ions. The Analytical Thermal Spike Model (ATSM) is applied whose main features are reviewed. The track data of Gd2Ti2O7 exhibit scaling features which mean simple quantitative relationships with track sizes of other insulators controlled only by a single materials parameter (MP), the melting temperature Tm. A composition independent track formation mechanism is responsible for the effect leading to the evolution of identical temperature distributions in these insulators when Se/N=constant (N-number density of atoms). The Re2-Se track evolution curve is described in the whole range of Se without the application of any individual fitting parameter and MPs apart Tm; the threshold for track formation Set=6.1/14.4 keV/nm for E 8 MeV/nucleon, respectively. The unique role of Tm is a highly important limitation for the mechanism of track formation. The uniform behavior and the underlying composition independent mechanism are discussed.