Microstructural changes which were induced by neutron irradiation, to fluences of up to 5.5 x 1021/m2 (>0.1MeV), were investigated by means of conventional and high-resolution electron microscopy. The irradiation-induced defects were suggested to be so-called cascade defects, which probably consisted of amorphous regions. The mean size of the defects was 3.2nm. This was comparable to the low-temperature coherence length in the a-b plane of the compound.

T.Yano, M.Pekala, A.Q.He, A.Wisniewski, M.L.Jenkins: Physica C, 1995, 247[1-2], 55-61