The growth of low dislocation density Sr1−x,Bax Nb2O6 crystals

The dislocation structures of both pure and Nd doped strontium barium niobate crystals, grown by the Czochralski method, were studied using an etch pit technique. It was determined that dislocations in the boule were being propagated from the seed and were confined to the center of the crystal. Typical dislocation density was 5x10⁴ cm⁻². Through the careful control of growth parameters and use of seed material cut from the dislocation free outer portion of a crystal, it was possible to grow crystals with very low dislocation densities, 1x10² cm⁻², and on occasion dislocation free crystals.