The observation of oscillatory behaviour in swift heavy ion irradiated quasicrystals

The effect of 835 MeV Kr irradiation at 90 K on a stable icosahedral quasicrystal (Al65Cu25Fe5V5) is discussed here. A Kr-beam of this energy was chosen in order to keep the stopping power ∼1300 eV/Å in accordance with our previous work [Nucl. Instrum. Meth. B, 156 (1999) 201], while increasing the travelled path in which strong electronic excitations occur (≫sample thickness). The ratio ρ(φ)/ρ(0) {resistivity at fluence φ/resistivity at zero fluence} of quasicrystal goes through oscillatory changes, up to ∼1×1012 ions/cm2 where this ratio drops considerably. The ex situ XRD on the irradiated samples however shows the evidence of degradation of the structure after a critical fluence of 1×1011 ions/cm2. From the ex situ XRD measurements, this degradation does not seem to increase with further fluence up to φ=1×1013 ions/cm2.