Dislocations in Strontium Barium Niobate

Abstract

The distribution of dislocations in strontium barium niobate (SBN) crystals is examined by etching and by optical microscopy, and the sources of the dislocations are also investigated. The dislocations can be put into three categories according to the characteristics of distribution patterns. The dislocations concentrated in the central region of the crystal originate from the dislocations and the residual surface damages in the seed. The dislocations aligned radially in the outer region of the crystal are generated by the lattice mismatching or thermal stress at the groove bottoms in the shoulder part of the crystal. Finally, the dislocations distributed randomly in the outer region are generated at the positions where Pt or SBN were adsorbed on the surface of the crystal body. Methods for eliminating the dislocations are also described.