Observation of twin boundary layers in pure and alloyed YBa2Cu3O7minus;dgr;

摘要

Using an electron diffraction technique, the thicknesses of the (nonorthorhombic) twin boundary layers were measured for pure and alloyed YBa2(Cu1minus;xMx)3O7minus;dgr;. Boundary thickness varied from sim;0.7 nm forM=Ni,x=0.02, and dgr;bartil;0 to sim;2.6 nm forM=Al,x=0.02, and dgr;bartil;0, while it was sim;1.0 nm for a pure YBa2Cu3O7. Highhyphen;resolution transmission electron imaging of similar specimens supports the existence of such twin boundary layers.