Irradiation Damage Caused by Ion Milling in Bismuth-Based Superconductors

Abstract
Thin specimens for transmission electron microscopy were prepared by an ion-milling technique under different conditions from Bi2Sr2Ca n-1Cu n O x superconductors with different phases (n=1, 2 and 3). They suffered ion irradiation damage so that a structural change from a crystalline to an amorphous state occurred locally. The damage rate depends on the species of phase, the crystal orientations and the milling conditions. It is slightly suppressed when specimens are cooled down to about 77 K during thinning.