Morphology and defect structures of novel relaxor ferroelectric single crystals Pb(Mg1/3Nb2/3)O-3-PbTiO3

High-performance relaxer ferroelectric single crystals Pb(Mg1/3Nb2/3)O-3-Pb TiO3 have been grown successfully by a modified Bridgman method. They have the size of 25 x 25 x 50 mm(3) and are of pure perovskite phases with tetra gonal or rhombohedral structures. Their {001} faces appear dominantly, whic h can be interpreted by the model of anionic coordination polyhedral growth units. Main macro defects observed under optical microscopes and SEM can b e reduced or removed by improving growth parameters after understanding the ir formation mechanism. 71 degrees or 109 degrees macrodomains in rhombohed ral PMNT 76/24 crystals and 90 degrees macrodomains in tetragonal PMNT 65/3 5 crystals have been observed by optical microscopes. It has been found tha t the transition from microdomains to macrodomains can be induced by compos itions. Both the imaging mechanism of non-180 degrees domains and the relat ion between domain configurations and ferroelectric phase transition have b een analyzed.