Defects in La_2CuO_4 and La_(1.86)Sr_(0.14)CuO4 single crystals

摘要

La2CuO4 and La1.86Sr0.14CuO4 single crystals were obtained by traveling solvent floating zone method. There were five kinds of defects in these single crystals: cracks, inclusions, gas bubbles, unhomogeneous distribution of Sr2+, and substructures. CH3COOH aqueous solution was used to etch these single crystals, and the etch-pit density was calculated.The formation mechanism of these defects was discussed. It is suggested that the good preparation of raw materials and the stringent growth conditions play an important role in growing high quality single crystals.