Single crystals which had been irradiated with 75MeV B ions and 230MeV Au ions were investigated by using transmission electron microscopy. In addition to columnar and cascade defects, another type of defect with a stair-step morphology was observed in all of the samples. Such defects usually existed in the area where the density of the deposited ion energy was lower than that required to produce cascade defects. Analysis of the defect microstructure, and the location of the defect in the target material, indicated that this type of defect was neither a simple crack nor an ordinary irradiation-induced defect.

Stair-Step Columnar Defects in Ion-Irradiated Bi2Cu2Sr2CaO8 Crystals. D.X.Huang, Y.Sasaki, Y.Ikuhara: Physica C, 2000, 339[4], 281-6