Hydrothermal synthesis, characterization and growth mechanism of single crystal lead titanate pyrochlore dendrites

Abstract

Lead titanate pyrochlore (Pb₂Ti₂O₆) dendrites have been synthesized via hydrothermal treatment of the mixture of lead and titanium hydroxides with the use of ammonia. The products were characterized by XRD, FESEM, TEM, HRTEM, SAED and EDX, respectively. TEM and FESEM show that an individual Pb₂Ti₂O₆ pyrochlore dendrite is composed of a long central trunk and more than three rows of secondary branches. Furthermore, the secondary branches cross the long central trunk exhibiting a cross-like morphology. The SAED patterns reveal the dendrites are single crystalline in nature. And the HRTEM images further demonstrate that both the trunk and the branches all grow along <112> directions. Based on the time-dependent experiments, the analyses of the effects of ammonia and the configuration of cubic pyrochlore structure, the growth mechanism of the single crystal Pb₂Ti₂O₆ pyrochlore dendrites was discussed.