Defect study in cuprate monocrystals by neutron topography and selective etching

Using neutron tomography and selective etching study of oxide superconductor monocrystals and related systems Nd2-xCexCuO4 (x = 0-0.17), La1.84Sr0.16CuO4 and YBa2Cu3O7-y is carried out. At dislocations densities above 103-104 cm2, observation of separate low-angle boundaries extending to the sample sizes and being of the order of hundred micron distant each other, is stated. The boundaries are oriented along [100] and [010] crystallographic axes, and unit disorientation is of the order of several angular seconds. In La1.84Sr0.16CuO4 crystals on the surface, which had not been treeted after growth microcrack type defects were detected besides etching holes, and in YBa2Cu3O7-y crystal - twinned structure