1995 Volume 103 Issue 1194 Pages 195-198
Bi2Sr2CaCu2Ox single crystals were irradiated with 18MeV Fe8+ ion at room temperature. Superconductive property and microstructure of the samples after the irradiation were investigated by magnetization hysteresis (ΔM) and transmission electron microscopy (TEM). ΔM was enhanced by increasing ion dose up to 1×1012ions/cm2, but decreased at the density of 1×1013ions/cm2. The ion irradiation produced ellipse-like amorphous defects with the size of several nm, which may behave as flux pinning centers inside the crystals. The defects were formed in the band region of 0.5μm at the depth of about 4.5μm from the surface. The number of defects were equal to several times of applied ion dose. The optimum dose for improving superconductivity should be dominated by the defect size and spacing of defects to avoid overlapping among the defects.