MORPHOLOGICAL EFFECTS OF GRINDING ON BISMUTH-BASED CUPRATE SUPERCONDUCTORS

Morphological changes of bismuth-based cuprate superconductors, such a s the 2223 phase, via a small mechanical force were studied mainly by means of high-resolution transmission electron microscopy and atomic f orce microscopy. Even light mechanical grinding of the sintered 2223 s amples led to the formation of superfine particles that had a width of similar to 5 nm. Moreover, we found first that the superfine particle s had a discrete thickness of odd numbers of a half unit length c/2 of the 2223 phase, e.g. 1.9 nm, 5.6 mm, and so on, The formation of the superfine particles was due to cleavage at Bi-O double layers that wer e bound weakly to each other in a unit cell.