Micro-twin and antiphase domain boundaries in the orthorhombic phase of La 2− x (Sr, Ba) xCuO 4

Abstract

We have studied the intricate microstructure of La 2− x (Sr, Ba) x CuO 4 at temperatures where the samples exhibit orthorhombic symmetry. We show that, in addition to the twin boundaries, antiphase domain boundaries also play a key role in the formation of the microstructural network. Antiphase boundaries which have not been reported previously in this system, become a predominant feature particularly in the areas where the regular twin domain boundaries are not present. We also show that the intricate microstructure can be fully understood by considering the possible configurations between the twin and antiphase boundaries which arise from the tilting of the CuO 6 octahedra.