Thin films were irradiated with 200MeV 40Ca, 1162MeV or 2640MeV 197Au, and 1404MeV 238U ions. Radiation-induced defects in the films were investigated by means of cross-sectional and plane-view high-resolution electron microscopy. This showed that swift heavy ions produced well-defined latent columnar tracks that consisted of entirely amorphized material that was divided, by a sharp transition, from the surrounding crystalline material. It was found that the continuous columnar defects which resulted from 197Au and 238U bombardment were more efficient current pinning centers than were the scattered defect cascades which resulted from 40Ca bombardment.

J.Wiesner, C.Trholt, J.G.Wen, H.W.Zandbergen, G.Wirth, H.Füss: Physica C, 1996, 268[1-2], 161-72